Original Research
Prosthesis Use and Satisfaction Among Persons With Dysvascular Lower Limb Amputations Across Postacute Care Discharge Settings Emily V. Roth, BA, Liliana E. Pezzin, PhD, JD, Emily L. McGinley, MS, MPH, Timothy R. Dillingham, MD, MS Objective: To test the hypotheses that patients undergoing major lower limb amputations who received postacute care at an inpatient rehabilitation facility (IRF) would experience higher prosthesis use and satisfaction and lower prosthesis-related adverse effects than those treated at a skilled nursing facility (SNF) or at home. Design: Population-based, observational, prospective, multicenter study. Setting: Hospitals and communities in 2 racially and geographically diverse states. Participants: Patients 21 years and older who were identified during the surgical acute care stay as undergoing major lower limb amputations. Main Outcome Measures: Prosthesis use; satisfaction with prosthesis’ comfort, appearance, and gait; and the presence of skin irritation, pain, and wounds as a result of prosthesis use. Methods: Two-stage instrumental variable models applied to data collected from medical records and patient interviews. Results: Only 149 (50.2%) of the 297 study participants had a prosthesis at the 6-month follow-up. Regression-adjusted outcomes indicate that patients treated at IRFs used their prosthesis more hours per week (52.8 versus 36.2 h/wk or 46% higher use), were less likely to experience prosthesis-related pain (16% versus 33.7%) and were significantly more likely to be satisfied with their gait (76.1% versus 59.3%) than were patients treated at SNFs. No significant differences in outcomes were found between patients who received care at an IRF and patients who were discharged home. Conclusions: These results add to the growing body of literature suggesting a general pattern of better outcomes for persons with vascular-related amputations who receive postacute care at IRFs relative to SNFs. PM R 2014;6:1128-1136
INTRODUCTION Although estimates vary, the incidence of diabetes has reached epidemic proportions worldwide and is predicted to rise steadily in the coming years. As a consequence, the number of persons who will undergo a lower limb amputation as a result of a dysvascular cause is also expected to increase because of the higher incidence and prevalence of comorbid conditions, such as diabetes and peripheral vascular disease [1,2]. The use of a prosthesis is a critical factor associated with a person’s ability to return to the majority of his or her usual activities and reintegrate into daily routines [3]. Despite the increasing prevalence of amputations and the great potential for enhancement of function through prosthetic rehabilitation, little is known about barriers to and determinants of prosthesis use and satisfaction and related services among persons with dysvascular amputations. The amputation of a lower limb presents a significant challenge in how the person navigates and functions in today’s highly mobile society. Quality of life among persons with major amputations is affected by the physical limitations and emotional toll posed by the loss of functionality and change in body structure [3-8]. Rehabilitation and the use of a prosthetic limb after an amputation enable the patient to remain not only mobile but also PM&R
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E.V.R. Medical College of Wisconsin, Milwaukee, WI Disclosure: nothing to disclose L.E.P. Department of Medicine and Center for Patient Care and Outcomes Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226. Address correspondence to: L.E.P.; e-mail: [email protected] Disclosure: grants, National Institutes of Health/National Institute of Child Health and Human Development/National Center for Medical Rehabilitation Research (R29HD36414, R01HD36414) E.L.M. Department of Medicine and Center for Patient Care and Outcomes Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226 Disclosure: nothing to disclose T.R.D. Department of Physical Medicine and Rehabilitation, University of Pennsylvania, Philadelphia, PA Disclosure: grants, National Institutes of Health/National Institute of Child Health and Human Development/National Center for Medical Rehabilitation Research (R29HD36414, R01HD36414) Submitted for publication April 17, 2013; accepted May 21, 2014.
ª 2014 by the American Academy of Physical Medicine and Rehabilitation Vol. 6, 1128-1136, December 2014 http://dx.doi.org/10.1016/j.pmrj.2014.05.024
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independent, which tends to improve the patient’s physical and mental well-being [9,10]. The availability and successful use of a prosthesis has been shown to facilitate a return to work [11-13], enable better physical functioning [14-17], increase participation in leisure activities [9,14,16], and improve the patient’s mental health [18]. Previous studies have demonstrated that time to prosthesis fitting [8,19], as well as the patient’s age [7,13,19,20], gender [3,20], and income are significant correlates of prosthesis use and satisfaction [20]. The quality of the device fitting is also an important predictor of prosthetic use and satisfaction because poorly fitted prostheses often lead to discomfort, pain, wounds, and other undesirable adverse effects [3,4,12,16,21,22]. With a few notable exceptions [15,23-26], existing literature related to prosthetic use has not focused on the role of the postacute care setting with regard to the decision to use a prosthesis and satisfaction with the device. The process of ensuring timely and proper prosthesis fitting, including subsequent adjustments and attention to adverse consequences of prosthesis use, is likely to vary across postacute care settings, making the rehabilitation setting a potentially important predictor of prosthesis use and satisfaction. The purpose of this study was to test the hypotheses that patients undergoing a major dysvascular lower limb amputation who received postacute care at inpatient rehabilitation facilities (IRFs) would be more likely to be fitted with a prosthesis, report higher use of and greater satisfaction with their prosthesis, and experience a lower incidence of adverse effects associated with prosthesis use than would patients receiving postacute care at skilled nursing facilities (SNFs) or at home.
METHODS Study Population This study is part of a larger project designed to examine the comparative effectiveness of alternative postacute care settings (IRFs, SNFs, and home) in improving physical, social, and psychological outcomes among patients undergoing major lower limb amputations. Additional details about the study design and sample selection can be found in the report by Dillingham et al [27]. In brief, patients identified during the surgical acute care stay as undergoing major lower limb amputations at 18 hospitals in Baltimore, MD, and Milwaukee, WI, were asked to participate in this prospective, observational study. Potentially eligible patients—those scheduled to undergo a dysvascular lower limb amputation at the foot or at a higher level—were approached by a trained interviewer who described the study and obtained informed consent. Patients were ineligible if they were aged 21 years or younger, were undergoing amputations as a result of a nondysvascular cause (eg, related to trauma or congenital disease), were unable to cognitively provide consent (as
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determined by administration of the Short Portable Mental Status Questionnaire [28]), were non-English speaking, or had a history of stroke or paraplegia. Patients who died during their acute hospital stay were withdrawn from the study. All appropriate Institutional Review Boards approved this study.
Sources of Data Information was collected consistently between 2002 and 2006 by trained interviewers who used structured surveys. Data were obtained from 3 different sources: (1) clinical data were abstracted from acute care medical charts; (2) a faceto-face interview was performed prior to or during the acute surgical hospitalization to collect preamputation (baseline) information; and (3) a follow-up telephone interview was conducted 6 months after acute care discharge. At the follow-up 6-month interview, information was obtained on postamputation measures of health and functional status, in addition to the development of secondary medical conditions, limb problems with both residual and nonamputated limb, prosthesis fitting, and use and satisfaction with the prosthesis if the patient was fitted with a device.
Key Variable Definitions Items assessing prosthetic use and satisfaction were drawn from Gauthier-Gagnon and Grise’s Prosthetic Profiles of the Amputee [29], a valid and reliable instrument designed specifically for use by persons with lower limb amputations, augmented by measures proposed by Legro et al [30] and Smith et al [31], which have been widely used in the field [19,20,32,33]. Patients who reported having a prosthesis at the 6-month follow-up were subsequently asked a number of questions relating to intensity of use (hours per week); satisfaction with the prosthesis appearance, comfort, and overall gait; presence of adverse outcomes stemming from prosthesis use, including skin irritations, pain, and wounds; and use of other assistive devices in addition to the prosthesis, using the past 4 weeks as the reference period. For the satisfaction questions, responses were based on a 5-point Likert scale recording satisfaction as not at all, slightly, moderately, quite well, and completely satisfied. Binary variables, in which respondents were coded as being satisfied if they reported being “quite well” or “completely satisfied” with the specific prosthesis characteristic, were then used as dependent variables in multivariate regression analyses. Postacute care setting, a categorical variable, was classified into 3 mutually exclusive groups as IRF, SNF, and discharge home. Information about the subject’s initial discharge setting and utilization of postacute care was obtained from self-reported data collected during the 6-month patient interview and reconciled with hospitals’ administrative records. (In cases in which a patient reported receiving postacute care at both an SNF and an IRF, the “definitive” setting
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was determined based on the place where the patient received most of his/her institutional postacute care during the follow-up period.) Amputation level was classified into 4 mutually exclusive categories as foot/ankle (transmetatarsal and above), unilateral transtibial (including below the knee and Symes amputations), unilateral transfemoral (including through knee and above knee levels), or bilateral amputations (excluding toe amputations). Patients classified as bilateral amputees had a preexisting (most often, transtibial) amputation and underwent a second contralateral amputation at the foot or a higher level during the index study period amputation surgery. In cases in which the patient had undergone an amputation prior to the index surgery, the final level of limb loss was used for classification of amputation level.
Statistical Analysis Basic descriptive statistics were used to characterize the sample population according to the subjects’ sociodemographic profile, amputation level, and health status. Descriptive information was compared across groups receiving postacute care at different settings (IRF, SNF, and home) using univariate test statistics (t and c2). Our main analyses, however, relied on multivariate regression models to test the hypotheses of a positive, independent effect of postacute rehabilitation received at an IRF, relative to SNF and home, on the use and satisfaction with one’s prosthesis, controlling for preamputation functioning and the array of potential confounders previously described. Given the observational nature of our study, subjects were not randomly “assigned” to alternative postacute care discharge destination, raising concerns about potentially biasing selection effects when comparing prosthesis use and satisfaction across settings. To address this problem, we applied a 2-stage instrumental variable model [34,35]. This procedure entailed estimating first the probability that patients would receive rehabilitation at each alternative postacute care setting. Coefficient estimates from this first stage were subsequently used to form individual-level predictions of the probability that each person would receive care at each setting for the entire sample. These predicted probabilities, rather than the actual indicators, were then used as regressors in the (second-stage) prosthesis use and satisfaction equations. In addition to variables hypothesized to influence prosthesis use and satisfaction directly, the first stage estimation also included a set of “instrumental variables”— factors often considered by discharge planners when making recommendations for postacute care placement—that are, however, not expected to affect outcomes directly, conditional on receipt of postacute care at alternative settings. These instrumental variables included preamputation living arrangements, number of potential caregivers in the household, and the architecture/accessibility of the patient’s home (eg, single floor and wheelchair accessibility). We tested the
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quality of our instruments using the overidentification statistics based on the partial R2 and F statistics on the excluded variables in the first-stage regression [36]. The adequacy of the instruments was also tested with respect to the extent to which they could be legitimately excluded from the second stage (prosthesis use and satisfaction) estimations, conditional on postacute care setting. For the second-stage regressions, an ordinary least square specification was used to examine factors affecting hours per week of prosthesis use. For satisfaction and adverse effects analyses—where the dependent variables took the value of 1 if the person was satisfied/experienced an adverse event, and 0 otherwise—probit specifications were used. In all equations, the contributions of the following explanatory factors were examined: the patient’s age (years), gender, race, ethnicity, marital status, household income, and insurance coverage; preamputation measures of disability (classified as none, limitations with instrumental activities of daily living [IADLs] only, 1-2 activities of daily living [ADLs], or 3þ ADLs) [37]; the presence and number of preexisting medical conditions [38]; the presence of any postoperative complications (eg, intensive care unit stay after surgery or infections); the number of outpatient physical therapy/occupational therapy (PT/OT) visits; the number of amputee clinic visits during the 6-month follow-up period; and the geographic state where acute care services were received. For prosthesis satisfaction and adverse effects equations, we further controlled for the presence of a soft inner socket liner. Based on the coefficient estimates from these (second stage) outcome equations, we calculated the adjusted independent effect of postacute care setting on each outcome by assuming all patients were treated, alternatively, at each of the 3 postacute care settings, while holding all other factors constant at their original levels. Unless otherwise noted, a P value of less than .05 was considered the critical level to determine statistical significance. However, P values between .05 and .10 are noted as well in all multivariate instrumental variable regressions. Associations approaching significance can provide further insight into postacute care setting effects on prosthetic use and satisfaction for which the P < .05 level is not realized because of the 2-stage modeling, which tends to increase standard errors of the “instrumented” coefficients [36]. All analyses were conducted using STATA 11.0 statistical software (StataCorp, College Station, TX).
RESULTS A total of 718 patients were approached about study participation before they underwent amputation, and 87.1% or 625 of those patients agreed to take part in the research study. During the initial screening interview, 277 patients were found to be ineligible because of previously determined exclusion criteria, including pre-existent stroke (regardless of
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severity, n ¼ 238), and/or temporary or permanent cognitive impairment that affected the patient’s ability to provide informed consent (n ¼ 20). As a result, 348 preamputation patients were eligible for study participation, with 297 of those patients completing 6-month follow-up interviews. Of those 297 patients, 149 reported having a prosthesis at the time of the follow-up. The latter 2 groups comprise the study samples for the purpose of these analyses. Of the 178 patients directly discharged to an IRF, 49 were subsequently discharged to an SNF after a relatively short IRF stay (mean ¼ 13, standard deviation [SD] ¼ 9 nights). Given that the majority of their care was provided at an SNF, these patients were assigned to the SNF category. The final distribution of patients by setting, therefore, was 129 (43.4%) at an IRF, 95 (32%) at an SNF, and 73 (24.6%) at home among patients who completed the follow-up interview, and 71 (47.6%), 44 (29.6%), and 34 (22.8%) at an IRF, SNF, and home, respectively, among patients who had a prosthesis at follow-up.
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Table 1 shows characteristics of patients who were enrolled in the study, those who completed the 6-month follow-up, and the subset of that group who reported having a prosthesis at the 6-month follow-up. Of note, no significant differences between the “enrolled” and “completed” groups were noted by age, race, gender, marital status, comorbidities, disability, or amputation levels. The majority of the 297 persons who completed the study were male, and 27.3% were African American or black. The mean age was slightly below Medicare eligibility (63.2 years old). Nearly 2 out of 5 patients had an annual income at or below $20,000, and just about 60% reported having limitations with either basic ADLs or IADLs. With respect to final amputation level, 45.8% were discharged from the index hospitalization with a unilateral amputation at the transtibial level. For 13.8%, the final amputation level was at the higher, transfemoral level, and more than one quarter became bilateral amputees at the time of the index amputation. About one third of all study participants
Table 1. Sociodemographic and health characteristics of the study sample
Age in years; mean (SD) Male (%) NoneAfrican American/black (%) Married (%) Comorbidities: mean (SD) Disability level (%) None IADL only 1-2 ADLs 3 ADLs Amputation level (%) Foot (transmetatarsal or above) Transfemoral Transtibial Bilateral Family income (%) $50,000 Missing information Insurance coverage (%) Medicare Medicaid Other Days of outpatient PT or OT* (%) 0 1-6 7þ Prosthetics appointments* (%) 0 1-2 3þ Unknown Attended an amputee clinic* (%)
Enrolled (N [ 348)
Completed Follow-up (N [ 297)
Had Prosthesis at Follow-up (N [ 149)
63.9 (13.2) 59.6 72.1 45.7 5.4 (2.1)
63.2 (13.3) 59.3 72.7 45.5 5.4 (2.1)
63.9 (13.2) 63.8 79.2 52.3 5.2 (2.2)
39.1 22.6 21.0 17.3
39.7 25.3 19.5 15.5
38.3 28.9 19.5 13.4
13.8 15.4 45.5 25.3
13.8 13.8 45.8 26.6
7.4 11.4 60.4 20.8
38.7 26.9 8.8 25.6
34.9 32.9 10.7 21.5,
71.0 8.3 20.7
68.5 4.7 26.9
37.7 12.5 49.8
24.2 12.7 63.1
59.5 25.0 8.1 7.4 7.7
0.0 33.6 58.4 8.1 12.2
SD ¼ standard deviation; IADL ¼ instrumental activity of daily living; ADL ¼ activity of daily living; PT ¼ physical therapy; OT ¼ occupational therapy. *During the 6-month postamputation study period.
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reported never receiving any outpatient PT or OT services, and only 7.7% reported attending an amputee clinic during the 6-month follow-up period. Of the 297 patients who completed the 6-month followup, 50.2% (n ¼ 149) reported having a prosthesis at the time of follow-up. Persons who had a prosthetic device at follow-up were more likely to be male (63.8%), none African American (79.2%), and married (52.3%) than were persons without a prosthesis at follow-up. Although no differences were found between persons with and without a prosthesis in terms of baseline comorbidity or disability level, a substantially higher proportion of patients with a prosthesis had their amputation at the transtibial level (60.4%). Patients with a prosthesis were also less likely than those without a prosthesis to be publicly insured (26.9% were covered by insurance other than Medicare or Medicaid) and reported receiving a higher number of PT/OT visits (63.1% received 7 or more PT/OT visits within the 6-month follow-up period), amputee clinic visits (12.2%), and prosthetic appointments (58.4% attended 3 or more prosthetic appointments). Table 2 presents summary statistics regarding prosthesis use, satisfaction, and adverse effects by postacute setting among persons with a prosthesis at the 6-month follow-up. Average use of the prosthesis among patients who had a device was 48.7 hours per week. The frequency of prosthesis use was lowest among patients who received postacute care at an SNF (40 h/wk). The mean time from amputation to first prosthesis fitting was 13.2 weeks with no discernible differences across postacute care settings. Most amputees appeared to be satisfied with the appearance (68.1%), gait
(68.1%), and comfort (62.1%) of their prosthesis, with patients receiving postacute care at IRFs consistently reporting the highest levels of satisfaction across domains. More than one quarter experienced skin irritations, 11.6% had wounds, and 21.1% experienced pain as a direct result of using their prosthesis. The majority (69.8%) of patients with a prosthesis also relied on wheelchairs as assistive devices to ambulate. Table 3 presents adjusted probabilities/outcomes based on coefficients from our 2-stage, instrumental variable analysis of the effect of postacute care setting on prosthesis use and satisfaction. These predicted probabilities/outcomes were computed by assuming that patients had been treated at each of the alternative postacute care settings, while holding all other factors, including selection and other potential confounders, constant at their original levels. The reported differences, therefore, represent the independent, selection-corrected effect of IRFs (relative to SNFs and home) on each outcome, after controlling for baseline functioning, socioeconomic variables, and other confounding variables previously described. Consistent with our hypothesis, the adjusted/predicted intensity of prosthesis use was 52.8 h/wk when persons were assumed to have received postacute care at an IRF, nearly 17 more hours per week (or 46% higher) than that of persons treated at an SNF. Persons receiving care at an IRF were also less than half as likely to experience prosthesisrelated pain as were those in SNFs (16% versus 33.7%, respectively). The likelihood of experiencing pain among persons in IRFs was also 34% lower than that of patients discharged directly home, although this difference did not
Table 2. Prosthesis use, satisfaction, adverse effects, and use of supportive devices among persons with a prosthetic device By Discharge Destination
Have prosthesis: N (% of completed sample) Among those with a prosthesis* Time to fitting (wk); mean (SD) Prosthetic use (h/wk) ; mean (SD)y Satisfied withz (%) Appearancey Gaity Comforty Adverse effects (%) Skin irritationsy Woundsy Painy Use of supportive device (%)y Cane(s) Crutches Walker Wheelchair (electric or manual)
Inpatient Rehabilitation
Skilled Nursing Facility
149 (50.2)
71 (55.0)
44 (46.3)
13.2 (6.5) 48.7 (34.3)
13.1 (6.4) 53.9 (32.8)
13.1 (6.4) 40.0 (32.5)
13.4 (7.1) 49.3 (38.3)
68.1 68.1 62.1
75.4 78.3 67.1
59.5 57.1 59.5
63.6 60.6 54.6
26.5 11.6 21.1
29.6 15.5 15.5
32.6 11.6 30.2
12.1 3.0 21.2
46.3 7.4 55.0 69.8
50.7 4.2 53.5 76.1
34.1 6.8 72.7 77.3
52.9 14.7 35.3 47.1
SD ¼ standard deviation. *Among the 149 patients who had an artificial limb or prosthesis at the 6-month follow-up. y Distribution across postacute care settings is significantly different at P < .05. z Satisfied with ¼ completely or quite well satisfied.
Home 34 (46.6)
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Table 3. Selection-corrected, adjusted outcomes by postacute care setting
Outcome Has a prosthesis (%)* Time to fitting (wk)y Prosthesis Use (h/wk)y Skin irritations (%)y Wounds (%)y Pain (%)y Satisfied withx Appearance (%)y Gaity Comforty
Postacute Care Setting
Difference
IRF SNF Home
IRF Versus IRF Versus SNF Home
49.1 5.3 36.2 38.1 20.9 33.7
55.1 6.5 50.8 13.5 3.6 24.2
0.8 0.4 16.6z 9.5 4.0 17.7z
6.8 1.6 2.0 15.1 13.3 8.2
71.5 63.8 76.1 59.3 66.0 55.6
64.6 59.7 61.2
7.7 16.8{ 10.4
6.9 16.4 4.8
48.3 4.9 52.8 28.6 16.9 16.0
IRF ¼ inpatient rehabilitation facility; SNF ¼ skilled nursing facility. *Adjusted/predicted outcomes are based on regression analyses that control for amputation level, comorbidities, perioperative complication, baseline disability, postoperative physical or occupational therapy, use of an amputee clinic, and sociodemographic and economic characteristics of patients, as well as self-selection into alternative settings. y Adjusted outcomes are based on regression analyses that control for the same set of covariates described in the previous footnote, as well as the presence of a soft liner in the prosthesis. z The underlying coefficient is statistically significant at .05 P < .10. x Satisfied with ¼ completely or quite well satisfied. { The underlying coefficient is statistically significant at P < .05.
achieve statistical significance at conventional levels primarily because of the relatively small sample (n ¼ 34) of amputees discharged home who used their prosthesis at the 6-month follow-up. Finally, with respect to satisfaction with the device, despite a general trend toward better outcomes among persons in IRFs relative to SNFs, only satisfaction with gait was statistically significant (16.8 adjusted percentage point difference, or þ28% increase) from 59.3% to 76.1% of persons in SNFs and IRFs, respectively.
DISCUSSION Our results suggest that, even after adjustments for selection into postacute care settings, patients receiving postacute care at an IRF were more intense users of a prosthetic device, were more likely to be satisfied with their gait, and experienced less pain associated with the use of a prosthesis than were patients who received rehabilitation care at an SNF. This finding underscores the utility of postacute care at an IRF to enable patients to overcome limb issues that might otherwise limit ambulation. Contrary to our hypothesis, no significant differences were noted between IRFs and SNFs with respect to the probability of having a prosthesis or time to prosthesis fitting. Time to prosthesis fitting has previously been shown to correlate with intensity of use and satisfaction
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with the prosthesis [19,39,40]. Although many factors may affect the timing to prosthesis fitting, including postsurgical complications and degree of wound healing, it seemed plausible to hypothesize that patients receiving rehabilitation care under the direct supervision of a physiatrist, as is characteristic of IRFs, would have been more likely to use and have been fitted sooner with a prosthetic device than were patients in SNFs. Finally, once selection was taken into account, no statistically significant differences were found in prosthetic use, satisfaction, or incidence of adverse effects as a result of prosthesis use between patients who received postacute care at an IRF and those who were discharged home directly. Postoperative amputation management continues to evolve with advances in prosthetic technology and rehabilitation techniques. Patients receiving postacute care at an IRF may be more likely to receive state-of-the-art rehabilitation treatment as a result of direct supervision by physiatrists and specialized nurses and therapists, along with more intensive and interdisciplinary rehabilitation care. The initial rehabilitation approach is designed to enable patients to gain independence from a wheelchair or use of crutch ambulation. Other goals are medical stabilization of comorbidities and management of residual limb edema and the surgical wound such that optimal healing takes place. Our results suggest that inpatient rehabilitation provided effective wound management, as evidenced by the comparable intensity of prosthesis use between patients who received postacute care at an IRF and at home despite the latter group’s substantially lower incidence of wound complications. When compared with postacute care received at SNFs, rehabilitation care in an inpatient rehabilitation setting is characterized by a greater intensity and variety of therapy services, interdisciplinary team management, and direct supervision by an attending physician. Persons using prosthetic devices have access to PT and OT, as well as prosthetic services designed to maximize limb care, optimal fit, and a positive experience with the device. The coordinated and more intense rehabilitation received at an inpatient rehabilitation unit, as well as the close medical monitoring, disposition planning, and patient and family education [41], may have influenced the greater intensity of prosthesis use observed in this study. In addition, study patients receiving postacute care at an IRF were more likely to have attended outpatient PT and/or OT during the 6-month follow-up than were patients in SNFs, factors likely contributing to greater frequency of prosthesis use directly and indirectly via their effects on more successful transitions to independent community living. This study contributes to the much-needed evaluation of the comparative effectiveness of alternative postacute care settings for the rehabilitation of the large and growing number of persons undergoing dysvascular amputations in the United States [42]. Our findings complement and are
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generally consistent with previous studies that have uncovered a beneficial relative effect of IRFs for a variety of other outcomes. For example, evidence suggests that persons with dysvascular amputations who received postacute care at an IRF at any time during the first 12 months after undergoing amputation are significantly more likely to achieve mobility success than are persons who never received postacute care at an IRF [15]. Persons with major lower limb amputations who received postacute care at an IRF also experienced improved emotional and mental health [18], were less likely to experience depression [18], and had better physical functioning and overall health [17] at 6 months after surgery than did their counterparts who received postacute care at an SNF or at home. In a study examining Medicare beneficiaries, postacute care at an IRF or unit was also associated with fewer subsequent amputations, better 12-month survival, and fewer inpatient admissions for nonamputationrelated issues, suggesting greater medical stability [43]. Taken together, these findings suggest that inpatient rehabilitation has positive and clinically meaningful effects on many dimensions of function and health after a limb amputation. Our study provided a unique opportunity to examine, prospectively, issues related to use and satisfaction with prosthetic devices for a racially and geographically diverse sample of persons with major dysvascular lower limb amputations. The 2-stage instrumental variable modeling enabled us to adjust for patient health status and other factors affecting both discharge destination/use of postacute care at alternative facilities and outcomes conditional on postacute care setting, thereby emulating, statistically, a scenario consistent with random assignment to alternative postacute care settings. Nonetheless, our study has several limitations. During the past decade, interest has increased in developing more comprehensive instruments to evaluate prosthetic use and satisfaction among persons with limb amputations [16,44,45]. Although our outcomes are based on validated and widely used measures, they are limited in scope and do not capture the richer set of items developed since the study’s inception. In addition, patients were asked to report use of alternative postacute care settings and other health care services over a 6-month follow-up period. Although our health care utilization variables may have some inherent inaccuracies as result of the 6-month recall period, there is no reason to believe that such measurement error, if present, biased any of our results because it is unlikely that (1) recall error would differ systematically by postacute care setting and (2) such differences would be correlated with prosthetic use and satisfaction. Another important limitation is the relatively small sample size of prosthesis users for the analyses of prosthesis satisfaction and adverse effects. Despite a relatively large initial sample (n ¼ 297), only half of our participants
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reported having a prosthesis at the 6-month follow-up, significantly limiting our statistical power to detect more subtle differences in outcomes across settings with respect to certain dimensions of these outcomes. Statistical power was especially low (.53) to detect differences in outcomes for patients in the home category, where only 34 of the 73 study subjects reported having a prosthesis at the 6-month follow-up period. Finally, for ethical and operational reasons, this study was not a randomized trial, and thus concerns about selection are clearly relevant. Acute care discharge planning is a complex process that draws on providers’ clinical judgment to triage patients to the postacute setting where they are expected to gain the most benefit from rehabilitation. Consideration is given to medical need and rehabilitation goals and tolerance, as well as the patient’s home situation and social support. By collecting information on factors likely to influence the acute care discharge process and applying 2-stage instrumental variable techniques, the leading technique to address endogeneity and self-selection in observational studies [46], the concern about selection bias stemming from nonrandom assignment to postacute care setting treatment groups was minimized, if not completely eliminated.
CONCLUSION A better understanding of factors associated with prosthetic use are of relevance for several important reasons. Successful vocational adaptation is often correlated with prosthetic use. Frequent prosthetic use and satisfaction with the device’s comfort, in particular, have been shown to significantly improve the prognosis for return to work among persons with limb loss [13,19]. Well-fit, comfortable, and easy-to-use prosthetic devices that enable a patient to carry out daily activities and maintain independence are therefore of paramount importance. The goal of rehabilitation for persons with limb amputations is to foster a rapid return to ADLs, including the ability to walk and to perform social and physical roles independently. A comfortable and effective prosthesis makes a positive contribution to the person’s ability to accomplish these tasks. Our results corroborate findings from earlier, single-setting studies and indicate that the sizeable and statistically significant association between receipt of postacute care at an IRF (relative to an SNF) and a higher intensity of prosthesis use persist even after adjustments for nonrandom discharge disposition. Our results also indicate that postacute rehabilitation care at an IRF leads to improved pain outcomes and increased satisfaction with prosthesis gait. These findings suggest that postacute care received at IRFs enhances the likelihood of a good match between the device and the patient’s needs relative to postacute care received at SNFs.
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REFERENCES 1. Danaei G, Finucane MM, Lu Y, et al. National, regional, and global trends in fasting plasma glucose and diabetes prevalence since 1980: Systematic analysis of health examination surveys and epidemiological studies with 370 country-years and 2.7 million participants. Lancet 2011;378:31-40. 2. Ziegler-Graham K, MacKenzie EJ, Ephraim PL, et al. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil 2008;89:422-429. 3. Poljak-Guberina R, Zivkovic O, Muljacic A, et al. The amputees and quality of life. Coll Antropol 2005;29:603-609. 4. Murray CD, Fox J. Body image and prosthesis satisfaction in the lower limb amputee. Disabil Rehabil 2002;24:925-931. 5. Hagberg K, Branemark R. Consequences of non-vascular trans-femoral amputation: A survey of quality of life, prosthetic use and problems. Prosthet Orthot Int 2001;25:186-194. 6. Sinha R, van den Heuvel WJ, Arokiasamy P. Factors affecting quality of life in lower limb amputees. Prosthet Orthot Int 2011;35:90-96. 7. Pell JP, Donnan PT, Fowkes FG, et al. Quality of life following lower limb amputation for peripheral arterial disease. Eur J Vasc Surg 1993;7: 448-451. 8. Chen MC, Lee SS, Hsieh YL, et al. Influencing factors of outcome after lower-limb amputation: A five-year review in a plastic surgical department. Ann Plast Surg 2008;61:314-318. 9. Schaffalitzky E, Gallagher P, Maclachlan M, et al. Understanding the benefits of prosthetic prescription: Exploring the experiences of practitioners and lower limb prosthetic users. Disabil Rehabil 2011;33: 1314-1323. 10. Zidarov D, Swaine B, Gauthier-Gagnon C. Quality of life of persons with lower-limb amputation during rehabilitation and at 3-month follow-up. Arch Phys Med Rehabil 2009;90:634-645. 11. Fisher K, Hanspal RS, Marks L. Return to work after lower limb amputation. Int J Rehabil Res 2003;26:51-56. 12. Gailey R, McFarland LV, Cooper RA, et al. Unilateral lower-limb loss: Prosthetic device use and functional outcomes in service members from Vietnam war and OIF/OEF conflicts. J Rehabil Res Dev 2010;47:317-331. 13. Millstein S, Bain D, Hunter GA. A review of employment patterns of industrial amputees—factors influencing rehabilitation. Prosthet Orthot Int 1985;9:69-78. 14. Matsen SL, Malchow D, Matsen FA 3rd. Correlations with patients’ perspectives of the result of lower-extremity amputation. J Bone Joint Surg Am 2000;82-A:1089-1095. 15. Czerniecki JM, Turner AP, Williams RM, et al. The effect of rehabilitation in a comprehensive inpatient rehabilitation unit on mobility outcome after dysvascular lower extremity amputation. Arch Phys Med Rehabil 2012;93:1384-1391. 16. Gallagher P, Maclachlan M. The Trinity Amputation and Prosthesis Experience Scales and quality of life in people with lower-limb amputation. Arch Phys Med Rehabil 2004;85:730-736. 17. Sauter CN, Pezzin LE, Dillingham TR. Functional outcomes of persons who underwent dysvascular lower extremity amputations: Effect of postacute rehabilitation setting. Am J Phys Med Rehabil 2013;92: 287-296. 18. Pezzin LE, Padalik SE, Dillingham TR. Effect of postacute rehabilitation setting on mental and emotional health among persons with dysvascular amputations. PM R 2013;5:583-590. 19. Pezzin LE, Dillingham TR, Mackenzie EJ, et al. Use and satisfaction with prosthetic limb devices and related services. Arch Phys Med Rehabil 2004;85:723-729. 20. Dillingham TR, Pezzin LE, MacKenzie EJ, et al. Use and satisfaction with prosthetic devices among persons with trauma-related amputations: A long-term outcome study. Am J Phys Med Rehabil 2001;80:563-571. 21. Raichle KA, Hanley MA, Molton I, et al. Prosthesis use in persons with lower- and upper-limb amputation. J Rehabil Res Dev 2008;45:961-972.
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22. Desmond D, Gallagher P, Henderson-Slater D, et al. Pain and psychosocial adjustment to lower limb amputation amongst prosthesis users. Prosthet Orthot Int 2008;32:244-252. 23. Stineman MG, Kurichi JE, Kwong PL, et al. Survival analysis in amputees based on physical independence grade achievement. Arch Surg 2009;144:543-551; discussion 552. 24. Stineman MG, Kwong PL, Xie D, et al. Prognostic differences for functional recovery after major lower limb amputation: Effects of the timing and type of inpatient rehabilitation services in the Veterans Health Administration. PM R 2010;2:232-243. 25. Kurichi JE, Small DS, Bates BE, et al. Possible incremental benefits of specialized rehabilitation bed units among veterans after lower extremity amputation. Med Care 2009;47:457-465. 26. van Eijk MS, van der Linde H, Buijck B, et al. Predicting prosthetic use in elderly patients after major lower limb amputation. Prosthet Orthot Int 2012;36:45-52. 27. Dillingham TR, Yacub JN, Pezzin LE. Determinants of postacute care discharge destination after dysvascular lower limb amputation. PM R 2011;3:336-344. 28. Folstein MF, Folstein SE, McHugh PR. “Mini-mental state.” A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-198. 29. Gauthier-Gagnon C, Grise MC. Prosthetic profile of the amputee questionnaire: Reliability and validity. Arch Phys Med Rehabil 1994;75: 1309-1314. 30. Legro MW, Reiber GD, Smith DG, et al. Prosthesis evaluation questionnaire for persons with lower limb amputations: Assessing prosthesis-related quality of life. Arch Phys Med Rehabil 1998;79: 931-938. 31. Smith DG, Ehde DM, Legro MW, et al. Phantom limb, residual limb, and back pain after lower extremity amputations. Clin Orthop Relat Res 1999;361:29-38. 32. Gauthier-Gagnon C, Grise MC, Potvin D. Predisposing factors related to prosthetic use by people with a transtibial and transfemoral amputation. J Prosthet Orthot 1998;10:99-109. 33. Gauthier-Gagnon C, Grise MC, Potvin D. Enabling factors related to prosthetic use by people with a transtibial and transfemoral amputation. Arch Phys Med Rehabil 1999;80:706-713. 34. Greene W. Econometric Analysis. 2nd ed. New York, NY: Macmillan; 1993. 35. Maddala G. Limited Dependent Variables and Qualitative Variables in Econometrics. New York, NY: Cambridge University Press; 1983. 36. Bound J, Jaeger D, Baker R. Problems with instrumental variables estimation when the correlation between the instruments and the endogenous explanatory variable is weak. J Am Stat Assoc 1995;90: 443-450. 37. Katz S, Ford AB, Moskwitz RW, et al. Studies of illness in the aged: The index of ADL: A standardized measure of biological and psychosocial function. JAMA 1963;185:914-919. 38. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol 1992;45:613-619. 39. Malone JM, Moore WS, Goldstone J, et al. Therapeutic and economic impact of a modern amputation program. Ann Surg 1979; 189:798-802. 40. Behel JM, Rybarczyk B, Elliott TR, et al. The role of perceived vulnerability in adjustment to lower extremity amputation: A preliminary investigation. Rehabil Psychol 2002;47:92-105. 41. Commission on Accreditation of Rehabilitation Facilities. Medical Rehabilitation Standards Manual. Tucson, AZ: Commission on Accreditation of Rehabilitation Facilities International; 2011. 42. Sansam K, Neumann V, O’Connor R, Bhakta B. Predicting walking ability following lower limb amputation: A systematic review of the literature. J Rehabil Med 2009;41:593-603.
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43. Dillingham TR, Pezzin LE. Rehabilitation setting and associated mortality and medical stability among persons with amputations. Arch Phys Med Rehabil 2008;89:1038-1045. 44. Franchignoni F, Orlandini D, Ferriero G, Moscato TA. Reliability, validity, and responsiveness of the Locomotor Capabilities Index in adults with lower-limb amputation undergoing prosthetic training. Arch Phys Med Rehabil 2004;85:743-748.
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45. Gallagher P, Franchignoni F, Giordano A, MacLachlan M. Trinity Amputation and Prosthesis Experience Scales (TAPES): A psychometric assessment using classical test theory and Rasch analysis. Am J Phys Med Rehabil 2010;89:487-496. 46. Methodology Committee of the Patient-Centered Outcomes Research Institute. Methodological standards and patient-centeredness in comparative effectiveness research: The PCORI perspective. JAMA 2012;307:1636-1640.
Prosthesis Use and Satisfaction Among Persons With Dysvascular Lower Limb Amputations Across Postacute Care Discharge Settings Emily V. Roth, BA, Liliana E. Pezzin, PhD, JD, Emily L. McGinley, MS, MPH, Timothy R. Dillingham, MD, MS Objective: To test the hypotheses that patients undergoing major lower limb amputations who received postacute care at an inpatient rehabilitation facility (IRF) would experience higher prosthesis use and satisfaction and lower prosthesis-related adverse effects than those treated at a skilled nursing facility (SNF) or at home. Design: Population-based, observational, prospective, multicenter study. Setting: Hospitals and communities in 2 racially and geographically diverse states. Participants: Patients 21 years and older who were identified during the surgical acute care stay as undergoing major lower limb amputations. Main Outcome Measures: Prosthesis use; satisfaction with prosthesis’ comfort, appearance, and gait; and the presence of skin irritation, pain, and wounds as a result of prosthesis use. Methods: Two-stage instrumental variable models applied to data collected from medical records and patient interviews. Results: Only 149 (50.2%) of the 297 study participants had a prosthesis at the 6-month follow-up. Regression-adjusted outcomes indicate that patients treated at IRFs used their prosthesis more hours per week (52.8 versus 36.2 h/wk or 46% higher use), were less likely to experience prosthesis-related pain (16% versus 33.7%) and were significantly more likely to be satisfied with their gait (76.1% versus 59.3%) than were patients treated at SNFs. No significant differences in outcomes were found between patients who received care at an IRF and patients who were discharged home. Conclusions: These results add to the growing body of literature suggesting a general pattern of better outcomes for persons with vascular-related amputations who receive postacute care at IRFs relative to SNFs. PM R 2014;6:1128-1136
INTRODUCTION Although estimates vary, the incidence of diabetes has reached epidemic proportions worldwide and is predicted to rise steadily in the coming years. As a consequence, the number of persons who will undergo a lower limb amputation as a result of a dysvascular cause is also expected to increase because of the higher incidence and prevalence of comorbid conditions, such as diabetes and peripheral vascular disease [1,2]. The use of a prosthesis is a critical factor associated with a person’s ability to return to the majority of his or her usual activities and reintegrate into daily routines [3]. Despite the increasing prevalence of amputations and the great potential for enhancement of function through prosthetic rehabilitation, little is known about barriers to and determinants of prosthesis use and satisfaction and related services among persons with dysvascular amputations. The amputation of a lower limb presents a significant challenge in how the person navigates and functions in today’s highly mobile society. Quality of life among persons with major amputations is affected by the physical limitations and emotional toll posed by the loss of functionality and change in body structure [3-8]. Rehabilitation and the use of a prosthetic limb after an amputation enable the patient to remain not only mobile but also PM&R
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E.V.R. Medical College of Wisconsin, Milwaukee, WI Disclosure: nothing to disclose L.E.P. Department of Medicine and Center for Patient Care and Outcomes Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226. Address correspondence to: L.E.P.; e-mail: [email protected] Disclosure: grants, National Institutes of Health/National Institute of Child Health and Human Development/National Center for Medical Rehabilitation Research (R29HD36414, R01HD36414) E.L.M. Department of Medicine and Center for Patient Care and Outcomes Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226 Disclosure: nothing to disclose T.R.D. Department of Physical Medicine and Rehabilitation, University of Pennsylvania, Philadelphia, PA Disclosure: grants, National Institutes of Health/National Institute of Child Health and Human Development/National Center for Medical Rehabilitation Research (R29HD36414, R01HD36414) Submitted for publication April 17, 2013; accepted May 21, 2014.
ª 2014 by the American Academy of Physical Medicine and Rehabilitation Vol. 6, 1128-1136, December 2014 http://dx.doi.org/10.1016/j.pmrj.2014.05.024
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independent, which tends to improve the patient’s physical and mental well-being [9,10]. The availability and successful use of a prosthesis has been shown to facilitate a return to work [11-13], enable better physical functioning [14-17], increase participation in leisure activities [9,14,16], and improve the patient’s mental health [18]. Previous studies have demonstrated that time to prosthesis fitting [8,19], as well as the patient’s age [7,13,19,20], gender [3,20], and income are significant correlates of prosthesis use and satisfaction [20]. The quality of the device fitting is also an important predictor of prosthetic use and satisfaction because poorly fitted prostheses often lead to discomfort, pain, wounds, and other undesirable adverse effects [3,4,12,16,21,22]. With a few notable exceptions [15,23-26], existing literature related to prosthetic use has not focused on the role of the postacute care setting with regard to the decision to use a prosthesis and satisfaction with the device. The process of ensuring timely and proper prosthesis fitting, including subsequent adjustments and attention to adverse consequences of prosthesis use, is likely to vary across postacute care settings, making the rehabilitation setting a potentially important predictor of prosthesis use and satisfaction. The purpose of this study was to test the hypotheses that patients undergoing a major dysvascular lower limb amputation who received postacute care at inpatient rehabilitation facilities (IRFs) would be more likely to be fitted with a prosthesis, report higher use of and greater satisfaction with their prosthesis, and experience a lower incidence of adverse effects associated with prosthesis use than would patients receiving postacute care at skilled nursing facilities (SNFs) or at home.
METHODS Study Population This study is part of a larger project designed to examine the comparative effectiveness of alternative postacute care settings (IRFs, SNFs, and home) in improving physical, social, and psychological outcomes among patients undergoing major lower limb amputations. Additional details about the study design and sample selection can be found in the report by Dillingham et al [27]. In brief, patients identified during the surgical acute care stay as undergoing major lower limb amputations at 18 hospitals in Baltimore, MD, and Milwaukee, WI, were asked to participate in this prospective, observational study. Potentially eligible patients—those scheduled to undergo a dysvascular lower limb amputation at the foot or at a higher level—were approached by a trained interviewer who described the study and obtained informed consent. Patients were ineligible if they were aged 21 years or younger, were undergoing amputations as a result of a nondysvascular cause (eg, related to trauma or congenital disease), were unable to cognitively provide consent (as
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determined by administration of the Short Portable Mental Status Questionnaire [28]), were non-English speaking, or had a history of stroke or paraplegia. Patients who died during their acute hospital stay were withdrawn from the study. All appropriate Institutional Review Boards approved this study.
Sources of Data Information was collected consistently between 2002 and 2006 by trained interviewers who used structured surveys. Data were obtained from 3 different sources: (1) clinical data were abstracted from acute care medical charts; (2) a faceto-face interview was performed prior to or during the acute surgical hospitalization to collect preamputation (baseline) information; and (3) a follow-up telephone interview was conducted 6 months after acute care discharge. At the follow-up 6-month interview, information was obtained on postamputation measures of health and functional status, in addition to the development of secondary medical conditions, limb problems with both residual and nonamputated limb, prosthesis fitting, and use and satisfaction with the prosthesis if the patient was fitted with a device.
Key Variable Definitions Items assessing prosthetic use and satisfaction were drawn from Gauthier-Gagnon and Grise’s Prosthetic Profiles of the Amputee [29], a valid and reliable instrument designed specifically for use by persons with lower limb amputations, augmented by measures proposed by Legro et al [30] and Smith et al [31], which have been widely used in the field [19,20,32,33]. Patients who reported having a prosthesis at the 6-month follow-up were subsequently asked a number of questions relating to intensity of use (hours per week); satisfaction with the prosthesis appearance, comfort, and overall gait; presence of adverse outcomes stemming from prosthesis use, including skin irritations, pain, and wounds; and use of other assistive devices in addition to the prosthesis, using the past 4 weeks as the reference period. For the satisfaction questions, responses were based on a 5-point Likert scale recording satisfaction as not at all, slightly, moderately, quite well, and completely satisfied. Binary variables, in which respondents were coded as being satisfied if they reported being “quite well” or “completely satisfied” with the specific prosthesis characteristic, were then used as dependent variables in multivariate regression analyses. Postacute care setting, a categorical variable, was classified into 3 mutually exclusive groups as IRF, SNF, and discharge home. Information about the subject’s initial discharge setting and utilization of postacute care was obtained from self-reported data collected during the 6-month patient interview and reconciled with hospitals’ administrative records. (In cases in which a patient reported receiving postacute care at both an SNF and an IRF, the “definitive” setting
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was determined based on the place where the patient received most of his/her institutional postacute care during the follow-up period.) Amputation level was classified into 4 mutually exclusive categories as foot/ankle (transmetatarsal and above), unilateral transtibial (including below the knee and Symes amputations), unilateral transfemoral (including through knee and above knee levels), or bilateral amputations (excluding toe amputations). Patients classified as bilateral amputees had a preexisting (most often, transtibial) amputation and underwent a second contralateral amputation at the foot or a higher level during the index study period amputation surgery. In cases in which the patient had undergone an amputation prior to the index surgery, the final level of limb loss was used for classification of amputation level.
Statistical Analysis Basic descriptive statistics were used to characterize the sample population according to the subjects’ sociodemographic profile, amputation level, and health status. Descriptive information was compared across groups receiving postacute care at different settings (IRF, SNF, and home) using univariate test statistics (t and c2). Our main analyses, however, relied on multivariate regression models to test the hypotheses of a positive, independent effect of postacute rehabilitation received at an IRF, relative to SNF and home, on the use and satisfaction with one’s prosthesis, controlling for preamputation functioning and the array of potential confounders previously described. Given the observational nature of our study, subjects were not randomly “assigned” to alternative postacute care discharge destination, raising concerns about potentially biasing selection effects when comparing prosthesis use and satisfaction across settings. To address this problem, we applied a 2-stage instrumental variable model [34,35]. This procedure entailed estimating first the probability that patients would receive rehabilitation at each alternative postacute care setting. Coefficient estimates from this first stage were subsequently used to form individual-level predictions of the probability that each person would receive care at each setting for the entire sample. These predicted probabilities, rather than the actual indicators, were then used as regressors in the (second-stage) prosthesis use and satisfaction equations. In addition to variables hypothesized to influence prosthesis use and satisfaction directly, the first stage estimation also included a set of “instrumental variables”— factors often considered by discharge planners when making recommendations for postacute care placement—that are, however, not expected to affect outcomes directly, conditional on receipt of postacute care at alternative settings. These instrumental variables included preamputation living arrangements, number of potential caregivers in the household, and the architecture/accessibility of the patient’s home (eg, single floor and wheelchair accessibility). We tested the
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quality of our instruments using the overidentification statistics based on the partial R2 and F statistics on the excluded variables in the first-stage regression [36]. The adequacy of the instruments was also tested with respect to the extent to which they could be legitimately excluded from the second stage (prosthesis use and satisfaction) estimations, conditional on postacute care setting. For the second-stage regressions, an ordinary least square specification was used to examine factors affecting hours per week of prosthesis use. For satisfaction and adverse effects analyses—where the dependent variables took the value of 1 if the person was satisfied/experienced an adverse event, and 0 otherwise—probit specifications were used. In all equations, the contributions of the following explanatory factors were examined: the patient’s age (years), gender, race, ethnicity, marital status, household income, and insurance coverage; preamputation measures of disability (classified as none, limitations with instrumental activities of daily living [IADLs] only, 1-2 activities of daily living [ADLs], or 3þ ADLs) [37]; the presence and number of preexisting medical conditions [38]; the presence of any postoperative complications (eg, intensive care unit stay after surgery or infections); the number of outpatient physical therapy/occupational therapy (PT/OT) visits; the number of amputee clinic visits during the 6-month follow-up period; and the geographic state where acute care services were received. For prosthesis satisfaction and adverse effects equations, we further controlled for the presence of a soft inner socket liner. Based on the coefficient estimates from these (second stage) outcome equations, we calculated the adjusted independent effect of postacute care setting on each outcome by assuming all patients were treated, alternatively, at each of the 3 postacute care settings, while holding all other factors constant at their original levels. Unless otherwise noted, a P value of less than .05 was considered the critical level to determine statistical significance. However, P values between .05 and .10 are noted as well in all multivariate instrumental variable regressions. Associations approaching significance can provide further insight into postacute care setting effects on prosthetic use and satisfaction for which the P < .05 level is not realized because of the 2-stage modeling, which tends to increase standard errors of the “instrumented” coefficients [36]. All analyses were conducted using STATA 11.0 statistical software (StataCorp, College Station, TX).
RESULTS A total of 718 patients were approached about study participation before they underwent amputation, and 87.1% or 625 of those patients agreed to take part in the research study. During the initial screening interview, 277 patients were found to be ineligible because of previously determined exclusion criteria, including pre-existent stroke (regardless of
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severity, n ¼ 238), and/or temporary or permanent cognitive impairment that affected the patient’s ability to provide informed consent (n ¼ 20). As a result, 348 preamputation patients were eligible for study participation, with 297 of those patients completing 6-month follow-up interviews. Of those 297 patients, 149 reported having a prosthesis at the time of the follow-up. The latter 2 groups comprise the study samples for the purpose of these analyses. Of the 178 patients directly discharged to an IRF, 49 were subsequently discharged to an SNF after a relatively short IRF stay (mean ¼ 13, standard deviation [SD] ¼ 9 nights). Given that the majority of their care was provided at an SNF, these patients were assigned to the SNF category. The final distribution of patients by setting, therefore, was 129 (43.4%) at an IRF, 95 (32%) at an SNF, and 73 (24.6%) at home among patients who completed the follow-up interview, and 71 (47.6%), 44 (29.6%), and 34 (22.8%) at an IRF, SNF, and home, respectively, among patients who had a prosthesis at follow-up.
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Table 1 shows characteristics of patients who were enrolled in the study, those who completed the 6-month follow-up, and the subset of that group who reported having a prosthesis at the 6-month follow-up. Of note, no significant differences between the “enrolled” and “completed” groups were noted by age, race, gender, marital status, comorbidities, disability, or amputation levels. The majority of the 297 persons who completed the study were male, and 27.3% were African American or black. The mean age was slightly below Medicare eligibility (63.2 years old). Nearly 2 out of 5 patients had an annual income at or below $20,000, and just about 60% reported having limitations with either basic ADLs or IADLs. With respect to final amputation level, 45.8% were discharged from the index hospitalization with a unilateral amputation at the transtibial level. For 13.8%, the final amputation level was at the higher, transfemoral level, and more than one quarter became bilateral amputees at the time of the index amputation. About one third of all study participants
Table 1. Sociodemographic and health characteristics of the study sample
Age in years; mean (SD) Male (%) NoneAfrican American/black (%) Married (%) Comorbidities: mean (SD) Disability level (%) None IADL only 1-2 ADLs 3 ADLs Amputation level (%) Foot (transmetatarsal or above) Transfemoral Transtibial Bilateral Family income (%) $50,000 Missing information Insurance coverage (%) Medicare Medicaid Other Days of outpatient PT or OT* (%) 0 1-6 7þ Prosthetics appointments* (%) 0 1-2 3þ Unknown Attended an amputee clinic* (%)
Enrolled (N [ 348)
Completed Follow-up (N [ 297)
Had Prosthesis at Follow-up (N [ 149)
63.9 (13.2) 59.6 72.1 45.7 5.4 (2.1)
63.2 (13.3) 59.3 72.7 45.5 5.4 (2.1)
63.9 (13.2) 63.8 79.2 52.3 5.2 (2.2)
39.1 22.6 21.0 17.3
39.7 25.3 19.5 15.5
38.3 28.9 19.5 13.4
13.8 15.4 45.5 25.3
13.8 13.8 45.8 26.6
7.4 11.4 60.4 20.8
38.7 26.9 8.8 25.6
34.9 32.9 10.7 21.5,
71.0 8.3 20.7
68.5 4.7 26.9
37.7 12.5 49.8
24.2 12.7 63.1
59.5 25.0 8.1 7.4 7.7
0.0 33.6 58.4 8.1 12.2
SD ¼ standard deviation; IADL ¼ instrumental activity of daily living; ADL ¼ activity of daily living; PT ¼ physical therapy; OT ¼ occupational therapy. *During the 6-month postamputation study period.
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reported never receiving any outpatient PT or OT services, and only 7.7% reported attending an amputee clinic during the 6-month follow-up period. Of the 297 patients who completed the 6-month followup, 50.2% (n ¼ 149) reported having a prosthesis at the time of follow-up. Persons who had a prosthetic device at follow-up were more likely to be male (63.8%), none African American (79.2%), and married (52.3%) than were persons without a prosthesis at follow-up. Although no differences were found between persons with and without a prosthesis in terms of baseline comorbidity or disability level, a substantially higher proportion of patients with a prosthesis had their amputation at the transtibial level (60.4%). Patients with a prosthesis were also less likely than those without a prosthesis to be publicly insured (26.9% were covered by insurance other than Medicare or Medicaid) and reported receiving a higher number of PT/OT visits (63.1% received 7 or more PT/OT visits within the 6-month follow-up period), amputee clinic visits (12.2%), and prosthetic appointments (58.4% attended 3 or more prosthetic appointments). Table 2 presents summary statistics regarding prosthesis use, satisfaction, and adverse effects by postacute setting among persons with a prosthesis at the 6-month follow-up. Average use of the prosthesis among patients who had a device was 48.7 hours per week. The frequency of prosthesis use was lowest among patients who received postacute care at an SNF (40 h/wk). The mean time from amputation to first prosthesis fitting was 13.2 weeks with no discernible differences across postacute care settings. Most amputees appeared to be satisfied with the appearance (68.1%), gait
(68.1%), and comfort (62.1%) of their prosthesis, with patients receiving postacute care at IRFs consistently reporting the highest levels of satisfaction across domains. More than one quarter experienced skin irritations, 11.6% had wounds, and 21.1% experienced pain as a direct result of using their prosthesis. The majority (69.8%) of patients with a prosthesis also relied on wheelchairs as assistive devices to ambulate. Table 3 presents adjusted probabilities/outcomes based on coefficients from our 2-stage, instrumental variable analysis of the effect of postacute care setting on prosthesis use and satisfaction. These predicted probabilities/outcomes were computed by assuming that patients had been treated at each of the alternative postacute care settings, while holding all other factors, including selection and other potential confounders, constant at their original levels. The reported differences, therefore, represent the independent, selection-corrected effect of IRFs (relative to SNFs and home) on each outcome, after controlling for baseline functioning, socioeconomic variables, and other confounding variables previously described. Consistent with our hypothesis, the adjusted/predicted intensity of prosthesis use was 52.8 h/wk when persons were assumed to have received postacute care at an IRF, nearly 17 more hours per week (or 46% higher) than that of persons treated at an SNF. Persons receiving care at an IRF were also less than half as likely to experience prosthesisrelated pain as were those in SNFs (16% versus 33.7%, respectively). The likelihood of experiencing pain among persons in IRFs was also 34% lower than that of patients discharged directly home, although this difference did not
Table 2. Prosthesis use, satisfaction, adverse effects, and use of supportive devices among persons with a prosthetic device By Discharge Destination
Have prosthesis: N (% of completed sample) Among those with a prosthesis* Time to fitting (wk); mean (SD) Prosthetic use (h/wk) ; mean (SD)y Satisfied withz (%) Appearancey Gaity Comforty Adverse effects (%) Skin irritationsy Woundsy Painy Use of supportive device (%)y Cane(s) Crutches Walker Wheelchair (electric or manual)
Inpatient Rehabilitation
Skilled Nursing Facility
149 (50.2)
71 (55.0)
44 (46.3)
13.2 (6.5) 48.7 (34.3)
13.1 (6.4) 53.9 (32.8)
13.1 (6.4) 40.0 (32.5)
13.4 (7.1) 49.3 (38.3)
68.1 68.1 62.1
75.4 78.3 67.1
59.5 57.1 59.5
63.6 60.6 54.6
26.5 11.6 21.1
29.6 15.5 15.5
32.6 11.6 30.2
12.1 3.0 21.2
46.3 7.4 55.0 69.8
50.7 4.2 53.5 76.1
34.1 6.8 72.7 77.3
52.9 14.7 35.3 47.1
SD ¼ standard deviation. *Among the 149 patients who had an artificial limb or prosthesis at the 6-month follow-up. y Distribution across postacute care settings is significantly different at P < .05. z Satisfied with ¼ completely or quite well satisfied.
Home 34 (46.6)
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Table 3. Selection-corrected, adjusted outcomes by postacute care setting
Outcome Has a prosthesis (%)* Time to fitting (wk)y Prosthesis Use (h/wk)y Skin irritations (%)y Wounds (%)y Pain (%)y Satisfied withx Appearance (%)y Gaity Comforty
Postacute Care Setting
Difference
IRF SNF Home
IRF Versus IRF Versus SNF Home
49.1 5.3 36.2 38.1 20.9 33.7
55.1 6.5 50.8 13.5 3.6 24.2
0.8 0.4 16.6z 9.5 4.0 17.7z
6.8 1.6 2.0 15.1 13.3 8.2
71.5 63.8 76.1 59.3 66.0 55.6
64.6 59.7 61.2
7.7 16.8{ 10.4
6.9 16.4 4.8
48.3 4.9 52.8 28.6 16.9 16.0
IRF ¼ inpatient rehabilitation facility; SNF ¼ skilled nursing facility. *Adjusted/predicted outcomes are based on regression analyses that control for amputation level, comorbidities, perioperative complication, baseline disability, postoperative physical or occupational therapy, use of an amputee clinic, and sociodemographic and economic characteristics of patients, as well as self-selection into alternative settings. y Adjusted outcomes are based on regression analyses that control for the same set of covariates described in the previous footnote, as well as the presence of a soft liner in the prosthesis. z The underlying coefficient is statistically significant at .05 P < .10. x Satisfied with ¼ completely or quite well satisfied. { The underlying coefficient is statistically significant at P < .05.
achieve statistical significance at conventional levels primarily because of the relatively small sample (n ¼ 34) of amputees discharged home who used their prosthesis at the 6-month follow-up. Finally, with respect to satisfaction with the device, despite a general trend toward better outcomes among persons in IRFs relative to SNFs, only satisfaction with gait was statistically significant (16.8 adjusted percentage point difference, or þ28% increase) from 59.3% to 76.1% of persons in SNFs and IRFs, respectively.
DISCUSSION Our results suggest that, even after adjustments for selection into postacute care settings, patients receiving postacute care at an IRF were more intense users of a prosthetic device, were more likely to be satisfied with their gait, and experienced less pain associated with the use of a prosthesis than were patients who received rehabilitation care at an SNF. This finding underscores the utility of postacute care at an IRF to enable patients to overcome limb issues that might otherwise limit ambulation. Contrary to our hypothesis, no significant differences were noted between IRFs and SNFs with respect to the probability of having a prosthesis or time to prosthesis fitting. Time to prosthesis fitting has previously been shown to correlate with intensity of use and satisfaction
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with the prosthesis [19,39,40]. Although many factors may affect the timing to prosthesis fitting, including postsurgical complications and degree of wound healing, it seemed plausible to hypothesize that patients receiving rehabilitation care under the direct supervision of a physiatrist, as is characteristic of IRFs, would have been more likely to use and have been fitted sooner with a prosthetic device than were patients in SNFs. Finally, once selection was taken into account, no statistically significant differences were found in prosthetic use, satisfaction, or incidence of adverse effects as a result of prosthesis use between patients who received postacute care at an IRF and those who were discharged home directly. Postoperative amputation management continues to evolve with advances in prosthetic technology and rehabilitation techniques. Patients receiving postacute care at an IRF may be more likely to receive state-of-the-art rehabilitation treatment as a result of direct supervision by physiatrists and specialized nurses and therapists, along with more intensive and interdisciplinary rehabilitation care. The initial rehabilitation approach is designed to enable patients to gain independence from a wheelchair or use of crutch ambulation. Other goals are medical stabilization of comorbidities and management of residual limb edema and the surgical wound such that optimal healing takes place. Our results suggest that inpatient rehabilitation provided effective wound management, as evidenced by the comparable intensity of prosthesis use between patients who received postacute care at an IRF and at home despite the latter group’s substantially lower incidence of wound complications. When compared with postacute care received at SNFs, rehabilitation care in an inpatient rehabilitation setting is characterized by a greater intensity and variety of therapy services, interdisciplinary team management, and direct supervision by an attending physician. Persons using prosthetic devices have access to PT and OT, as well as prosthetic services designed to maximize limb care, optimal fit, and a positive experience with the device. The coordinated and more intense rehabilitation received at an inpatient rehabilitation unit, as well as the close medical monitoring, disposition planning, and patient and family education [41], may have influenced the greater intensity of prosthesis use observed in this study. In addition, study patients receiving postacute care at an IRF were more likely to have attended outpatient PT and/or OT during the 6-month follow-up than were patients in SNFs, factors likely contributing to greater frequency of prosthesis use directly and indirectly via their effects on more successful transitions to independent community living. This study contributes to the much-needed evaluation of the comparative effectiveness of alternative postacute care settings for the rehabilitation of the large and growing number of persons undergoing dysvascular amputations in the United States [42]. Our findings complement and are
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generally consistent with previous studies that have uncovered a beneficial relative effect of IRFs for a variety of other outcomes. For example, evidence suggests that persons with dysvascular amputations who received postacute care at an IRF at any time during the first 12 months after undergoing amputation are significantly more likely to achieve mobility success than are persons who never received postacute care at an IRF [15]. Persons with major lower limb amputations who received postacute care at an IRF also experienced improved emotional and mental health [18], were less likely to experience depression [18], and had better physical functioning and overall health [17] at 6 months after surgery than did their counterparts who received postacute care at an SNF or at home. In a study examining Medicare beneficiaries, postacute care at an IRF or unit was also associated with fewer subsequent amputations, better 12-month survival, and fewer inpatient admissions for nonamputationrelated issues, suggesting greater medical stability [43]. Taken together, these findings suggest that inpatient rehabilitation has positive and clinically meaningful effects on many dimensions of function and health after a limb amputation. Our study provided a unique opportunity to examine, prospectively, issues related to use and satisfaction with prosthetic devices for a racially and geographically diverse sample of persons with major dysvascular lower limb amputations. The 2-stage instrumental variable modeling enabled us to adjust for patient health status and other factors affecting both discharge destination/use of postacute care at alternative facilities and outcomes conditional on postacute care setting, thereby emulating, statistically, a scenario consistent with random assignment to alternative postacute care settings. Nonetheless, our study has several limitations. During the past decade, interest has increased in developing more comprehensive instruments to evaluate prosthetic use and satisfaction among persons with limb amputations [16,44,45]. Although our outcomes are based on validated and widely used measures, they are limited in scope and do not capture the richer set of items developed since the study’s inception. In addition, patients were asked to report use of alternative postacute care settings and other health care services over a 6-month follow-up period. Although our health care utilization variables may have some inherent inaccuracies as result of the 6-month recall period, there is no reason to believe that such measurement error, if present, biased any of our results because it is unlikely that (1) recall error would differ systematically by postacute care setting and (2) such differences would be correlated with prosthetic use and satisfaction. Another important limitation is the relatively small sample size of prosthesis users for the analyses of prosthesis satisfaction and adverse effects. Despite a relatively large initial sample (n ¼ 297), only half of our participants
PROSTHESIS USE ACROSS POSTACUTE DISCHARGE SETTINGS
reported having a prosthesis at the 6-month follow-up, significantly limiting our statistical power to detect more subtle differences in outcomes across settings with respect to certain dimensions of these outcomes. Statistical power was especially low (.53) to detect differences in outcomes for patients in the home category, where only 34 of the 73 study subjects reported having a prosthesis at the 6-month follow-up period. Finally, for ethical and operational reasons, this study was not a randomized trial, and thus concerns about selection are clearly relevant. Acute care discharge planning is a complex process that draws on providers’ clinical judgment to triage patients to the postacute setting where they are expected to gain the most benefit from rehabilitation. Consideration is given to medical need and rehabilitation goals and tolerance, as well as the patient’s home situation and social support. By collecting information on factors likely to influence the acute care discharge process and applying 2-stage instrumental variable techniques, the leading technique to address endogeneity and self-selection in observational studies [46], the concern about selection bias stemming from nonrandom assignment to postacute care setting treatment groups was minimized, if not completely eliminated.
CONCLUSION A better understanding of factors associated with prosthetic use are of relevance for several important reasons. Successful vocational adaptation is often correlated with prosthetic use. Frequent prosthetic use and satisfaction with the device’s comfort, in particular, have been shown to significantly improve the prognosis for return to work among persons with limb loss [13,19]. Well-fit, comfortable, and easy-to-use prosthetic devices that enable a patient to carry out daily activities and maintain independence are therefore of paramount importance. The goal of rehabilitation for persons with limb amputations is to foster a rapid return to ADLs, including the ability to walk and to perform social and physical roles independently. A comfortable and effective prosthesis makes a positive contribution to the person’s ability to accomplish these tasks. Our results corroborate findings from earlier, single-setting studies and indicate that the sizeable and statistically significant association between receipt of postacute care at an IRF (relative to an SNF) and a higher intensity of prosthesis use persist even after adjustments for nonrandom discharge disposition. Our results also indicate that postacute rehabilitation care at an IRF leads to improved pain outcomes and increased satisfaction with prosthesis gait. These findings suggest that postacute care received at IRFs enhances the likelihood of a good match between the device and the patient’s needs relative to postacute care received at SNFs.
PM&R
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