1 April 1992
Volume 116
Number 7
Annals of Internal Medicine Supervised Fitness Walking in Patients with Osteoarthritis of the Knee A Randomized, Controlled Trial Pamela A. Kovar, PT, EdD; John P. Allegrante, PhD; C. Ronald MacKenzie, MD; Margaret G. E. Peterson, PhD; Bernard Gutin, PhD; and Mary E. Charlson, MD
• Objective: To assess the effect of a program of supervised fitness walking and patient education on functional status, pain, and use of medication in patients with osteoarthritis of the knee. • Design: An 8-week randomized, controlled trial. • Setting: Inpatient and outpatient services of an orthopedic hospital in an academic medical center. • Patients: A total of 102 patients with a documented diagnosis of primary osteoarthritis of one or both knees participated in the study. Data were obtained on 47 of 51 intervention patients and 45 of 51 control patients. • Interventions: An 8-week program of supervised fitness walking and patient education or standard routine medical care. • Measurements: Patients were evaluated and outcomes assessed before and after the intervention using a 6-minute test of walking distance and scores on the physical activity, arthritis impact, pain, and medication subscales of the Arthritis Impact Measurement Scale (AIMS). • Results: Patients randomly assigned to the walking program had a 70-meter increase in walking distance relative to their baseline assessment, which represents an improvement of 18.4% (95% CI, 9.8% to 27.0%). In contrast, controls showed a 17-meter decrease in walking distance relative to their baseline assessment (P < 0.001). Improvements in functional status as measured by the AIMS physical activity subscale were also observed in the walking group but not in the control group (P < 0.001); patients assigned to the walking program improved 39% (CI, 15.6% to 60.4%). Although changes in scores on the arthritis impact subscale were similar in the two groups (P = 0.093), the walking group experienced a decrease in arthritis pain of 27% (CI, 9.6% to 41.4%) (P = 0.003). Medication use was less frequent in the walking group than in the control group at the post-test (P = 0.08). • Conclusions: A program of supervised fitness walking and patient education can improve functional status without worsening pain or exacerbating arthritis-related symptoms in patients with osteoarthritis of the knee. Annals of Internal Medicine. 1992;116:529-534. From The Hospital for Special Surgery and Columbia University, New York, New York; and the Medical College of Georgia, Augusta, Georgia. For current author addresses, see end of text.
Osteoarthritis is a common, chronic, and progressively degenerative disease that afflicts over 16 million people in the United States (1-4). Prevalence of the condition increases with advanced age and is substantially higher in women than in men after the age of 45 years (5, 6). In later years, the chronic joint pain, loss of range of motion, and muscle weakness associated with radiologic osteoarthritis may lead to progressive limitations in mobility and an increasing need for medical services (7, 8). The primary goal in the clinical management of osteoarthritis is to maintain the functional status of the patient through the relief of symptoms. Treatment has traditionally involved anti-inflammatory agents, rangeof-motion exercises, and the avoidance of weight-bearing activity. Some investigators advocate walking as adjunct therapy (9), whereas others advise patients to limit walking and weight-bearing activities. No study has yet addressed the efficacy and safety of supervised fitness walking in the clinical management of patients with osteoarthritis of the knee. We report the results of a randomized, controlled study of the effect of a supervised program of fitness walking and patient education on functional status, complaints of pain, and the use of medication in patients with osteoarthritis of the knee. Methods Patients Patients participating in the study were recruited from a broad population base that included private patients who had a scheduled appointment with a cooperating physician at The Hospital for Special Surgery, a major referral center for patients with musculoskeletal and rheumatic diseases located at the New York Hospital-Cornell Medical Center; patients seen in the outpatient rheumatology and orthopedic clinics of the hospital; and patients identified through the New York Chapter of the Arthritis Foundation and various community-based sites in the vicinity of the hospital. Criteria for inclusion in the study included an age of 40 years or more; a documented diagnosis of chronic, stable, primary osteoarthritis of one or both knee joints in association with at least a 4-month history of symptomatic knee pain occurring during weight-bearing activities (patients with multiple joint involvement, those who had undergone major joint surgery, or had a lower joint prosthesis were also eligible); radiographic evidence of primary osteoarthritis of one or both knee joints, as demonstrated by joint-space narrowing, marginal spur formation, or subchondral cyst formation; the use of any of the various common, over-the-counter nonsteroidal anti-inflamma© 1992 American College of Physicians
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tory drugs 2 or more days per week; and nonparticipation in a regular program of physical activity at the time of enrollment. Patients were excluded if they had serious medical conditions for which exercise would be contraindicated, such as unstable angina, significant aortic stenosis, myocardial infarction within the last 3 months, or advanced chronic obstructive pulmonary disease; asymptomatic primary osteoarthritis of one or both knees; dementia or the inability to give informed consent; nonambulation due to amputation, stroke, or incapacitating arthritis; or involvement in another treatment program or study protocol. Using these criteria, we recruited 102 patients for our study from among 266 persons who were identified as being potentially eligible for participation. Of these 266 patients, 142 (53%) agreed to be further evaluated for eligibility; 12 of these 142 patients were excluded from participating in the study. Of the remaining 130 eligible patients, 28 refused to participate for various reasons. Baseline Measures Demographic data (age, sex, race, and education) and source of referral were recorded for each patient at baseline. The presence and severity of arthritis and comorbid conditions were documented using a standardized medical history questionnaire. Patients' history and current use of medication were also recorded; however, pill counts or other means were not used to corroborate self-reported medication use. A standardized physical examination, including height and weight measurements, was done. In addition, radiographic reports or standard antero-posterior films of patients9 knees were obtained from the primary physician before enrollment in the study and evaluated by either a rheumatologist or orthopedic surgeon to confirm the diagnostic presence of osteoarthritis. Radiographs were assessed specifically for the presence of joint-space narrowing, marginal spur formation, and subchondral cyst formation. The primary physician's permission for patient participation was obtained at this time.
Outcome Measures Outcome assessment in all patients was done using several independent measures of functional status, pain, and medication use at baseline and after the intervention. Functional status was assessed by a 6-minute test of walking distance performed by patients according to the method of Guyatt and colleagues (10). These investigators have found that the 6-minute test of walking distance reliably measures functional exercise capacity and demonstrates a moderate to strong correlation with tests using a treadmill or bicycle ergometer, and may be a more relevant indicator of functional status than are the high workloads associated with other exercise tests. The walking track in our study comprised a 114-foot hospital corridor that was free from distractions and obstacles. The surface of the corridor was tiled, hard, and smooth. Patients were instructed to walk as fast and as far as possible within the 6-minute period. During the test, patients were supervised by a physical therapist or trained research assistant. Distance walked was measured in feet and later converted to meters. Functional status was also measured by self-reported responses to selected subscales of the Arthritis Impact Measurement Scale (AIMS). The AIMS is a 67-item questionnaire that has been widely used in the study of rheumatic diseases and has shown the reliability, validity, stability, and sensitivity necessary to detect clinically meaningful changes in health status in clinical trials (11, 12). The AIMS physical activity and arthritis impact subscales were used to assess functional status. The physical activity subscale is a functional disability scale that measures the performance of common lower-extremity functions of daily living. Patients rated each item according to whether they had difficulty in performing various functional activities such as climbing stairs, bending, walking city blocks (in Manhattan, 20 north-south city blocks = 1 mile), and participating in strenuous sports, and whether they required the use of an assistive 530
device to walk. Scores were standardized on a range from 0 to 10 units, with higher scores representing the greater disability. The AIMS arthritis impact subscale is a global measure of health status (that is, physical, mental, and social well-being) in patients with arthritis. The scale has a horizontal, visualanalog format, and respondents are asked to rate how well they are doing (very well, well, fair, poor, or very poor) in terms of the ways that arthritis affects their health. For purposes of analysis, scores were standardized on a range of 0 to 10 units, with higher scores representing poorer health status. The AIMS arthritis pain subscale was used to assess pain. This measure also has a visual-analog format, and respondents are asked to rate their pain on a scale of 0 to 10 units, with higher scores representing greater pain. The AIMS medication subscale is used to estimate how often (always, very often, fairly often, sometimes, almost never, or never) during the past month patients have had to take medication for their arthritis. Responses are scored on a range from 0 to 6, with higher scores representing less frequent medication use. Interventions The experimental intervention was an 8-week, hospital-based program of indoor supervised fitness walking and patient education, the goal of which was to increase the functional capacity of patients by encouraging the adoption and maintenance of regular fitness walking. The program comprised 24 90-minute walking and education sessions that were designed and led by a registered physical therapist. Sessions occurred thrice weekly and included light stretching and strengthening exercises; guest speakers on the medical aspects of osteoarthritis and exercise; group discussion about barriers and benefits of walking; instruction in proper walking techniques and the maintenance of a walking program; supportive encouragement; and up to 30 minutes of walking. The walking portion of the program was conducted in a hospital corridor where patients walked on a tiled floor surface that was hard and smooth. Each patient wore supportive athletic shoes or shoes designed specifically for walking, cushioned athletic socks, and loose-fitting clothing. Each patient received an instructional guidebook with educational materials printed in large, bold-face type. The program and instructional materials were designed after conducting a patient-needs assessment and a review of the literature on walking programs; concepts from self-efficacy theory and educational strategies from behavioral psychology were incorporated into the program to help patients adhere to the walking regimen. A detailed description of the theory and strategies used in the intervention has been provided elsewhere (13). Each week, patients in the control group were contacted by the study coordinator via telephone to discuss the nature of their activities of daily living. After informed consent was obtained, patients were randomly assigned to either the 8-week walking program or to routine care. Unblocked randomization was done by the study coordinator after developing randomization schedules using a table of random numbers. Methodologic and logistical considerations required that two cohorts of patients (each with 20 to 30 patients) be enrolled in two separate intervention program cycles implemented across an 8-month period (October 1989 to May 1990). All program sessions and other aspects of the protocol were conducted at The Hospital for Special Surgery. A physician member of the investigator team provided medical supervision and was on call to respond to medical emergencies. Statistical Analysis Statistical analyses using chi-square, Kruskal-Wallis, and f-tests were done to test for group differences at baseline. Two-way repeated-measures analysis of variance was used to analyze the significance of before-after changes in distance walked; the Kruskal-Wallis test was used to analyze the differences in the two groups regarding the changes from baseline for each of the AIMS subscales. The hypothesis was that each of the outcome variables would be favorably influenced by the intervention. The overall alpha was set at 0.05 and a Bonfer-
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roni correction for multiple comparisons was used to adjust individual probabilities with an alpha of 0.01. Means are given ± SD, and 95% CIs are given when appropriate.
Table 1. Sociodemographic Characteristics of the Study Sample at Baseline Characteristic
Results Characteristics of the Sample Selected sociodemographic characteristics of the 102 patients at entry into the study are summarized in Table 1. Patients ranged in age from 40 to 89 years (mean age, 69 years). Both the intervention and control groups included more women than men, but gender distribution was similar in the two groups (P = 0.08). The two groups did not differ regarding race and education (P = 0.06 and P > 0.2, respectively). More people in the intervention group were married (P = 0.03). The average height by group was 163 ± 11 cm for patients in the walking program and 159 ± 9 cm for controls. The mean body weight was 77 ± 15 kg for the walking group and 76 ± 19 kg for the control group. No statistical difference was found between groups in the prevalence of major comorbid conditions or in patients' self-reported medication use in the management of any condition. The mean duration since diagnosis of osteoarthritis was 12 ± 12 years for the walking group and 11 ± 11 years for the control group. Eighteen patients in the walking program and 29 patients in the control group had unilateral (left or right) joint involvement, and 34 patients in the walking program and 21 patients in the control group had bilateral joint involvement. Compliance Forty-seven patients in the intervention group completed the 8-week walking program and were retested; 45 patients in the control group were also retested at the conclusion of the study. The average number of program sessions attended by patients assigned to the intervention group was 21 ± 6 sessions (range, 3 to 28 sessions); some patients attended more than three sessions per week. Post-test data were thus obtained for 92 of the 102 patients initially recruited to the study within the corresponding study period, except for 2 of the controls from the first program cycle.
Attrition Ten patients dropped out of the study. Of the five withdrawals in the intervention group, one was arthritisrelated (that is, the patient underwent a total knee replacement) and four were non-arthritis-related (one patient died of a cause judged to be unrelated to the intervention, one had a hip fracture due to a fall during a program session, one feared that walking might exacerbate a heart condition, and one reported family problems). Of the five withdrawals in the control group, one was due to a fractured hip after a fall and four were non-arthritis-related (one patient had a sprained ankle, one had a dental problem, and two had family problems).
Intervention Group (n - 52)
Control Group (n = 50)
Mean age*, y 70.38 ± 9 . 1 1 68.48 ± 1 1 . 3 2 Sex, n 12 Male 5 Female 40 45 Race, n Black 7 1 Hispanic 1 2 41 White 50 Marital status, n Married 18 5 Unmarried 34 45 Education, n 22 20 College graduate 10 < 4 years college 15 High school graduate 13 11 < 11th grade 5 6
P Valuet >0.2 0.08 0.06
0.03 >0.2
* Mean is given ± SD. t All P values are for comparisons between the intervention and control groups.
Outcomes Baseline and post-intervention measurements are summarized in Table 2. After the intervention, the walking distance in the experimental group increased an average of 70 meters from a baseline of 381 ± 114 meters, which represents an 18.4% increase in distance walked (CI, 9.8% to 27.0%). In contrast, the mean distance walked in 6 minutes by control patients decreased an average of 17 meters from a baseline of 356 ± 130 meters (P < 0.001). Male patients in the experimental group walked, on average, 73 meters farther than female patients at the post-test assessment; in the control group, men walked, on average, 31 meters farther than women. There were no between-subject differences in the walking distances of either male or female patients (P = 0.02). Furthermore, the difference due to gender did not vary according to the study group (P > 0.02). The effect of unilateral as opposed to bilateral joint involvement was also analyzed; differences were not significant (P > 0.2). Similarly, analysis of marital status revealed no statistically different effect on walking distance (P = 0.07). On the AIMS physical activity subscale, virtually no change from baseline was detected in the control group, but the intervention group demonstrated an average improvement of 2.41 units from an average baseline score of 6.15 ± 2.27 units (P < 0.001), which represents an improvement of 39% (CI, 15.6% to 60.4%). Scores on the AIMS arthritis impact subscale improved an average of 1.70 units from an average baseline score of 4.56 units in the intervention group and an average of 0.79 units from a baseline score of 3.85 units in the control group (P = 0.093). Scores on the AIMS arthritis pain subscale improved an average of 1.38 units from an average baseline score of 5.15 ± 1.99 units in the intervention group but only 0.10 units from the baseline score of 4.87 ± 2.31 units in the control group (P — 0.003). The change from baseline in the interven-
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Table 2. Outcome Measures at Baseline and after the Intervention* Measure
Baseline
6-minute walk, m AIMS subscales Physical activity Arthritis impact Arthritis pain Medications use
Post-Intervention Control Intervention Group Group (n = 47) (PI = 45)
P Valuet
339 ± 125
< 0.001
Intervention Group (n = 47)
Control Group (n = 45)
381 ± 114
356 ± 130
451 ± 118
5.72 3.85 4.87 2.64
3.74 2.86 3.77 3.64
6.15 4.56 5.15 2.80
± ± ± ±
2.27 2.14 1.99 1.65
± ± ± ±
2.49 2.38 2.31 1.68
± ± ± ±
2.69 1.88 1.73 1.92
5.96 3.06 4.77 2.90
± ± ± ±
2.32 1.91 2.12 2.02
< 0.001 0.093 0.003 0.08
* All 47 intervention patients completed baseline and post-intervention testing and had paired values for all five outcome measures. However, post-intervention values for all measures were obtained for only 44 of the 45 control patients; one control subject did not have paired values for the walk test. For the AIMS physical activity and arthritis impact subscales, scores are standardized on a range from 0 to 10 units, with higher scores representing greater disability and poorer health status. The AIMS arthritis pain subscale is scored 0 to 10, with higher scores representing greater pain. The AIMS medication subscale is scored from 0 to 6, with higher scores representing less frequent medication use. AIMS = Arthritis Impact Measurement Scale. t P values are for between-group comparisons regarding the differences in pretest to post-test changes.
tion group represents an improvement of 27% (CI, 9.6% to 41.4%). Scores on the AIMS medication use subscale have a different directionality from the other subscales (that is, higher scores reflect the use of less medication and lower scores reflect the use of more medication). The scores on this measure improved an average of 0.84 units from a baseline of 2.80 ± 1.65 units in the intervention group but only 0.26 units from a baseline score of 2.64 ± 1.68 units in the control group (P = 0.08). Discussion Evidence from recent epidemiologic studies (14-19) has demonstrated the overall beneficial health effects of physical activity in general and in patients with arthritis in particular (20-24). Minor and colleagues (21, 22), for example, have demonstrated that patients with osteoarthritis and rheumatoid arthritis are significantly deconditioned when compared with healthy age- and sexmatched controls. Although such patients have poor aerobic fitness because of both the disease and inactivity* several studies have indicated that participation in a low-impact exercise program (for example, swimming, bicycling, or walking) can improve aerobic fitness without adverse effects on the joints (21-23, 25-32). However, although these studies have suggested that patients with osteoarthritis show improvement in stamina, strength, and the ability to do housework or to engage in social activity, as well as reductions in joint pain, after participation in physical activity, these studies have not been definitive because of methodologic limitations and small sample sizes. Walking has been recommended as a gradual, safe, and effective form of physical activity for improving aerobic fitness in people who have a low tolerance for exercise because of illness (33). Although walking protocols used for healthy persons have involved as many as 20 weeks of training, some studies have demonstrated that aerobic fitness may be improved by as much as 15% to 30% after only 3 weeks of training (33-36). For example, among a small sample both of patients with osteoarthritis and of patients with rheumatoid arthritis, Price and colleagues (37) showed that walking safely and effectively produced significant in532
creases in aerobic fitness without triggering symptomatic flares. After a 12-week program of supervised indoor walking, patients demonstrated a 20% improvement in mean maximal oxygen consumption and an 8% increase in the mean distance walked in a brisk 5-minute walk. In addition to these outcomes, several studies have demonstrated that low-level programs of walking can also produce significant psychosocial benefits, such as mood elevation and a reduction of depression and anxiety (36, 38, 39). Walking may also be helpful in improving compliance with recommendations to increase physical activity. Many studies of compliance with exercise regimens have shown that program dropout rates are related to the intensity of the exercise regimen. Evidence suggests that higher-intensity programs of physical activity are associated with higher attrition rates, whereas walking may be more easily adopted and maintained (36). Exercise as adjunct therapy is not uniformly accepted in clinical practice in the management of patients with osteoarthritis of the knee, and thus patients are frequently advised to curtail such activity. Although walking has received some study, almost all of the investigations have focused on showing the aerobic benefits of walking in such patients, rather than the effect of walking on functional status. In the absence of data on the safety and efficacy of walking to improve functional status, both physicians and their patients are often uncertain about whether walking may be safely prescribed and undertaken in the management of osteoarthritis of the knee. Our study provides empirical support for the hypothesis that a program of supervised fitness walking and supportive patient education can be an important function-enhancing intervention in the clinical management of patients with osteoarthritis of the knee. It is the single largest randomized, controlled trial yet done to assess the effect of supervised fitness walking and patient education on functional status in patients with osteoarthritis. Two methodologic limitations of our study require comment. First, the control group did not receive an equal co-intervention. In planning the study, we did
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consider bringing control patients to the hospital three times each week during the course of the 8-week intervention period in order to provide a strictly equal cointervention; however, this was simply not feasible. Instead, we decided to provide the control patients with telephone contact three times during each week of the 8-week intervention period, which we believe provided sufficient attention. Second, it was not possible to blind the physical therapist who conducted all outcome assessments as well as the intervention program for experimental subjects. Although this constitutes a limitation of the study, we do not believe that this limitation substantially compromised the validity of our results. The functional status outcome measures of the AIMS are patient self-reports and thus are relatively uninfluenced by the individual conducting the interviews. Moreover, the 6-minute test of distance walked was done according to a standardized protocol that was adhered to throughout the study and thus minimized the potential for any differential in the application of the testing procedure across groups. Despite these limitations, we believe that the results of our study of a program of supervised fitness walking and patient education are clinically relevant. These results included an improvement in distance patients were able to walk and changes in self-reported physical activity and pain on a widely used scale of arthritis-related functional status. Moreover, we believe the findings should be considered generalizable to a broad patient population because the patients recruited to participate in our study were, on average, older (average age, 69.4 years), were more frail, and had considerably more joint involvement than patients in previous studies. Also, in contrast to patients in previous studies, our patients were not newly diagnosed with osteoarthritis. In our study, walking did not appear to worsen pain or exacerbate arthritis-related symptoms, a key consideration for both patients and clinicians. However, the fact that one patient (a 70-year-old woman) who was participating in the walking program fell and fractured a hip during one of the supervised sessions (requiring subsequent surgical repair) must be taken into consideration when assessing the overall benefits and costs of this intervention. However, one control patient also suffered a fall-related hip fracture during the study period, suggesting that this group is at risk for such an adverse event. Consequently, the risk for falling must be assessed and balanced with the potential benefits of supervised fitness walking when considering frail elderly patients for such a program. An index of the risk for falling that was developed by Tinetti and colleagues (40) can be useful in identifying potentially high-risk patients and should be used in screening older patients before enrollment in any walking program. Finally, it is important to point out that the effect on the outcome variables of interest in this study was achieved as a result of the combined effect of both supervised fitness walking and the psychosocial benefits associated with patient education and social support. Although our study was not designed to examine the differential contributions or additive effects of the multiple components of this intervention, it is possible that walking alone would not have produced the same im-
provement in outcomes that we observed. Other studies have shown the beneficial effect of psychosocial interventions and especially of social support in patients with arthritis (41, 42) and other diseases (43), and therefore the importance of the psychosocial benefit derived from the educational portion and the supportive group format of the intervention program should not be underestimated. In conclusion, our results show a strong and what we judge to be a clinically significant effect of supervised fitness walking and patient education on independent measures of the functional status of patients with osteoarthritis of the knee; this effect was achieved without exacerbating pain or triggering flares. Our results are consistent with the findings from previous studies that have demonstrated the aerobic benefits of walking in patient populations whose physical capacity has been significantly degraded by chronic joint disease. Our findings provide compelling evidence of a potentially valuable role for supervised fitness walking and supportive patient education in the management of patients with osteoarthritis. We are currently assessing the longterm outcome of this intervention in a follow-up study of these patients. This trial was limited to patients with osteoarthritis of the lower extremities, and the utility of such a program for patients with other chronic arthritic conditions (for example, degenerative joint disease of the hip and lower back) warrants further investigation. Acknowledgments: The authors thank the patients and physicians who agreed to participate in the study; Kate Lorig, RN, DrPH, of the Stanford Arthritis Center and Marian Minor, PT, PhD, of the University of Missouri who provided helpful insights during the early stages of planning the study; Mark Kasper, MS, and Jeanne Marie Cioppa-Mosca, PT, MBA, who assisted in collecting data; Stephen Paget, MD, who facilitated patient recruitment; Louis L. Harris, MS, PT, the late Michael Kroll, MA, PT, Marita Murrman, RN, MS, and Yvonne Webbe, RD, MS, who provided supportive assistance throughout the study; James C. Otis, PhD, and Sherry Backus, PT, who assisted in conducting gait analyses; and members of the Cornell Arthritis Center's Research Methodology Core who contributed helpful comments on earlier drafts of the paper. Grant Support: In part by a dissertation research grant to Dr. Kovar from the Arthritis Foundation and by National Institutes of Health Multipurpose Arthritis Center Program Grant No. 1 P60 AR38520-01A1 from the National Institute for Arthritis and Musculoskeletal and Skin Diseases. Requests for Reprints: John P. Allegrante, PhD, Cornell Arthritis and Musculoskeletal Diseases Center, The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. Current Author Addresses: Drs. Kovar, Allegrante, MacKenzie, Peterson, and Charlson: The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. Dr. Gutin: Department of Pediatrics and Georgia Prevention Institute, Medical College of Georgia, Augusta GA 30912-3710.
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26. Ekblom B, Lovgren O, Alderin M, Firdstrom M, Satterstrom G. Physical performance in patients with effect rheumatoid arthritis. Scand J Rheumatol. 1974;3:121-5. 27. Ekblom B, Lovgren O, Alderin M, Firdstrom M. Effect of shortterm physical training on patients with rheumatoid arthritis I. Scand J Rheumatol. 1975;41:80-6. 28. Ekblom B, Lovgren O, Alderin M, Firdstrom M, Satterstrom G. Effect of short-term physical training on patients with rheumatoid arthritis. A six-month follow-up study. Scand J Rheumatol. 1975;4: 87-91. 29. Nordemar R, Berg U, Ekblom B, Edstrom L. Changes in muscle fibre size and physical performance in patients with rheumatoid arthritis after 7 months physical training. Scand J Rheumatol. 1976; 5:233-8. 30. Nordemar R, Ekblom B, Zachrisson L, Lundqvist K. Physical training in rheumatoid arthritis: a controlled long-term study. I. Scand J Rheumatol. 1981;10:17-23. 31. Nordemar R. Physical training in rheumatoid arthritis: A controlled long-term study. II. Functional capacity and general attitudes. Scand J Rheumatol. 1981;10:25-30. 32. Nordesjo LO, Nordgren B, Wigren A, Kostad K. Isometric strength and endurance in patients with severe rheumatoid arthritis or osteoarthritis in the knee joints. A comparative study in healthy men and women. Scand J Rheumatol. 1983;12:152-6. 33. Shoenfeld Y, Keren G, Shimoni T, Birnfeld C, Sonar E. Walking: a method for rapid improvement of physical fitness. JAMA. 1980;243: 2062-3. 34. Pollock ML, Miller HS Jr, Janeway R, Linnerud AC, Robertson B, Valentino R. Effects of walking on body composition and cardiovascular function of middle-aged men. J Applied Physiol. 1971 ;30: 126-30. 35. Rippe JM, Ward A, Porcari JP, Freedson PS. Walking for health and fitness. JAMA. 1988;259:2720-4. 36. Rippe JM, Ward A, Porcari JP, Freedson PS, O'Hanley S, Wilkie S. The cardiovascular benefits of walking. Prac Cardiol. 1989;15:66-72. 37. Price LG, Hewett JE, Kay DR, Minor MA. Five-minute walking test of aerobic fitness for people with arthritis. Arthritis Care Res. 1988;1:33-7. 38. Porcari J, McCarron R, Kline G, Freedson PS, Ward A, Rippe JM. Is fast walking an adequate aerobic training stimulus for 30-to-69year-old men and women? Physician Sports Med. 1987;15:119-29. 39. Stern MJ, Cleary P. National exercise and heart disease project: psychosocial changes observed during a low-level exercise program. Arch Intern Med. 1981;141:1463-7. 40. Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons Irving in the community. N Engl J Med. 1988;319: 1701-7. 41. Achterberg-Lawlis J. The psychological dimension of arthritis. J Consult Clin Psychol. 1982;40:984-92. 42. Summers MN, Haley WE, Reveille JD, Alarcon GS. Radiographic assessment and psychologic variables as predictors of pain and functional impairment in osteoarthritis of the knee or hip. Arthritis Rheum. 1988;31:204-9. 43. Spiegel D, Bloom JR, Kraemer HC, Gottheil E. Effect of psychosocial treatment on survival of patients with metastatic breast cancer. Lancet. 1989;2:888-91.
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Volume 116
Number 7
Annals of Internal Medicine Supervised Fitness Walking in Patients with Osteoarthritis of the Knee A Randomized, Controlled Trial Pamela A. Kovar, PT, EdD; John P. Allegrante, PhD; C. Ronald MacKenzie, MD; Margaret G. E. Peterson, PhD; Bernard Gutin, PhD; and Mary E. Charlson, MD
• Objective: To assess the effect of a program of supervised fitness walking and patient education on functional status, pain, and use of medication in patients with osteoarthritis of the knee. • Design: An 8-week randomized, controlled trial. • Setting: Inpatient and outpatient services of an orthopedic hospital in an academic medical center. • Patients: A total of 102 patients with a documented diagnosis of primary osteoarthritis of one or both knees participated in the study. Data were obtained on 47 of 51 intervention patients and 45 of 51 control patients. • Interventions: An 8-week program of supervised fitness walking and patient education or standard routine medical care. • Measurements: Patients were evaluated and outcomes assessed before and after the intervention using a 6-minute test of walking distance and scores on the physical activity, arthritis impact, pain, and medication subscales of the Arthritis Impact Measurement Scale (AIMS). • Results: Patients randomly assigned to the walking program had a 70-meter increase in walking distance relative to their baseline assessment, which represents an improvement of 18.4% (95% CI, 9.8% to 27.0%). In contrast, controls showed a 17-meter decrease in walking distance relative to their baseline assessment (P < 0.001). Improvements in functional status as measured by the AIMS physical activity subscale were also observed in the walking group but not in the control group (P < 0.001); patients assigned to the walking program improved 39% (CI, 15.6% to 60.4%). Although changes in scores on the arthritis impact subscale were similar in the two groups (P = 0.093), the walking group experienced a decrease in arthritis pain of 27% (CI, 9.6% to 41.4%) (P = 0.003). Medication use was less frequent in the walking group than in the control group at the post-test (P = 0.08). • Conclusions: A program of supervised fitness walking and patient education can improve functional status without worsening pain or exacerbating arthritis-related symptoms in patients with osteoarthritis of the knee. Annals of Internal Medicine. 1992;116:529-534. From The Hospital for Special Surgery and Columbia University, New York, New York; and the Medical College of Georgia, Augusta, Georgia. For current author addresses, see end of text.
Osteoarthritis is a common, chronic, and progressively degenerative disease that afflicts over 16 million people in the United States (1-4). Prevalence of the condition increases with advanced age and is substantially higher in women than in men after the age of 45 years (5, 6). In later years, the chronic joint pain, loss of range of motion, and muscle weakness associated with radiologic osteoarthritis may lead to progressive limitations in mobility and an increasing need for medical services (7, 8). The primary goal in the clinical management of osteoarthritis is to maintain the functional status of the patient through the relief of symptoms. Treatment has traditionally involved anti-inflammatory agents, rangeof-motion exercises, and the avoidance of weight-bearing activity. Some investigators advocate walking as adjunct therapy (9), whereas others advise patients to limit walking and weight-bearing activities. No study has yet addressed the efficacy and safety of supervised fitness walking in the clinical management of patients with osteoarthritis of the knee. We report the results of a randomized, controlled study of the effect of a supervised program of fitness walking and patient education on functional status, complaints of pain, and the use of medication in patients with osteoarthritis of the knee. Methods Patients Patients participating in the study were recruited from a broad population base that included private patients who had a scheduled appointment with a cooperating physician at The Hospital for Special Surgery, a major referral center for patients with musculoskeletal and rheumatic diseases located at the New York Hospital-Cornell Medical Center; patients seen in the outpatient rheumatology and orthopedic clinics of the hospital; and patients identified through the New York Chapter of the Arthritis Foundation and various community-based sites in the vicinity of the hospital. Criteria for inclusion in the study included an age of 40 years or more; a documented diagnosis of chronic, stable, primary osteoarthritis of one or both knee joints in association with at least a 4-month history of symptomatic knee pain occurring during weight-bearing activities (patients with multiple joint involvement, those who had undergone major joint surgery, or had a lower joint prosthesis were also eligible); radiographic evidence of primary osteoarthritis of one or both knee joints, as demonstrated by joint-space narrowing, marginal spur formation, or subchondral cyst formation; the use of any of the various common, over-the-counter nonsteroidal anti-inflamma© 1992 American College of Physicians
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tory drugs 2 or more days per week; and nonparticipation in a regular program of physical activity at the time of enrollment. Patients were excluded if they had serious medical conditions for which exercise would be contraindicated, such as unstable angina, significant aortic stenosis, myocardial infarction within the last 3 months, or advanced chronic obstructive pulmonary disease; asymptomatic primary osteoarthritis of one or both knees; dementia or the inability to give informed consent; nonambulation due to amputation, stroke, or incapacitating arthritis; or involvement in another treatment program or study protocol. Using these criteria, we recruited 102 patients for our study from among 266 persons who were identified as being potentially eligible for participation. Of these 266 patients, 142 (53%) agreed to be further evaluated for eligibility; 12 of these 142 patients were excluded from participating in the study. Of the remaining 130 eligible patients, 28 refused to participate for various reasons. Baseline Measures Demographic data (age, sex, race, and education) and source of referral were recorded for each patient at baseline. The presence and severity of arthritis and comorbid conditions were documented using a standardized medical history questionnaire. Patients' history and current use of medication were also recorded; however, pill counts or other means were not used to corroborate self-reported medication use. A standardized physical examination, including height and weight measurements, was done. In addition, radiographic reports or standard antero-posterior films of patients9 knees were obtained from the primary physician before enrollment in the study and evaluated by either a rheumatologist or orthopedic surgeon to confirm the diagnostic presence of osteoarthritis. Radiographs were assessed specifically for the presence of joint-space narrowing, marginal spur formation, and subchondral cyst formation. The primary physician's permission for patient participation was obtained at this time.
Outcome Measures Outcome assessment in all patients was done using several independent measures of functional status, pain, and medication use at baseline and after the intervention. Functional status was assessed by a 6-minute test of walking distance performed by patients according to the method of Guyatt and colleagues (10). These investigators have found that the 6-minute test of walking distance reliably measures functional exercise capacity and demonstrates a moderate to strong correlation with tests using a treadmill or bicycle ergometer, and may be a more relevant indicator of functional status than are the high workloads associated with other exercise tests. The walking track in our study comprised a 114-foot hospital corridor that was free from distractions and obstacles. The surface of the corridor was tiled, hard, and smooth. Patients were instructed to walk as fast and as far as possible within the 6-minute period. During the test, patients were supervised by a physical therapist or trained research assistant. Distance walked was measured in feet and later converted to meters. Functional status was also measured by self-reported responses to selected subscales of the Arthritis Impact Measurement Scale (AIMS). The AIMS is a 67-item questionnaire that has been widely used in the study of rheumatic diseases and has shown the reliability, validity, stability, and sensitivity necessary to detect clinically meaningful changes in health status in clinical trials (11, 12). The AIMS physical activity and arthritis impact subscales were used to assess functional status. The physical activity subscale is a functional disability scale that measures the performance of common lower-extremity functions of daily living. Patients rated each item according to whether they had difficulty in performing various functional activities such as climbing stairs, bending, walking city blocks (in Manhattan, 20 north-south city blocks = 1 mile), and participating in strenuous sports, and whether they required the use of an assistive 530
device to walk. Scores were standardized on a range from 0 to 10 units, with higher scores representing the greater disability. The AIMS arthritis impact subscale is a global measure of health status (that is, physical, mental, and social well-being) in patients with arthritis. The scale has a horizontal, visualanalog format, and respondents are asked to rate how well they are doing (very well, well, fair, poor, or very poor) in terms of the ways that arthritis affects their health. For purposes of analysis, scores were standardized on a range of 0 to 10 units, with higher scores representing poorer health status. The AIMS arthritis pain subscale was used to assess pain. This measure also has a visual-analog format, and respondents are asked to rate their pain on a scale of 0 to 10 units, with higher scores representing greater pain. The AIMS medication subscale is used to estimate how often (always, very often, fairly often, sometimes, almost never, or never) during the past month patients have had to take medication for their arthritis. Responses are scored on a range from 0 to 6, with higher scores representing less frequent medication use. Interventions The experimental intervention was an 8-week, hospital-based program of indoor supervised fitness walking and patient education, the goal of which was to increase the functional capacity of patients by encouraging the adoption and maintenance of regular fitness walking. The program comprised 24 90-minute walking and education sessions that were designed and led by a registered physical therapist. Sessions occurred thrice weekly and included light stretching and strengthening exercises; guest speakers on the medical aspects of osteoarthritis and exercise; group discussion about barriers and benefits of walking; instruction in proper walking techniques and the maintenance of a walking program; supportive encouragement; and up to 30 minutes of walking. The walking portion of the program was conducted in a hospital corridor where patients walked on a tiled floor surface that was hard and smooth. Each patient wore supportive athletic shoes or shoes designed specifically for walking, cushioned athletic socks, and loose-fitting clothing. Each patient received an instructional guidebook with educational materials printed in large, bold-face type. The program and instructional materials were designed after conducting a patient-needs assessment and a review of the literature on walking programs; concepts from self-efficacy theory and educational strategies from behavioral psychology were incorporated into the program to help patients adhere to the walking regimen. A detailed description of the theory and strategies used in the intervention has been provided elsewhere (13). Each week, patients in the control group were contacted by the study coordinator via telephone to discuss the nature of their activities of daily living. After informed consent was obtained, patients were randomly assigned to either the 8-week walking program or to routine care. Unblocked randomization was done by the study coordinator after developing randomization schedules using a table of random numbers. Methodologic and logistical considerations required that two cohorts of patients (each with 20 to 30 patients) be enrolled in two separate intervention program cycles implemented across an 8-month period (October 1989 to May 1990). All program sessions and other aspects of the protocol were conducted at The Hospital for Special Surgery. A physician member of the investigator team provided medical supervision and was on call to respond to medical emergencies. Statistical Analysis Statistical analyses using chi-square, Kruskal-Wallis, and f-tests were done to test for group differences at baseline. Two-way repeated-measures analysis of variance was used to analyze the significance of before-after changes in distance walked; the Kruskal-Wallis test was used to analyze the differences in the two groups regarding the changes from baseline for each of the AIMS subscales. The hypothesis was that each of the outcome variables would be favorably influenced by the intervention. The overall alpha was set at 0.05 and a Bonfer-
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roni correction for multiple comparisons was used to adjust individual probabilities with an alpha of 0.01. Means are given ± SD, and 95% CIs are given when appropriate.
Table 1. Sociodemographic Characteristics of the Study Sample at Baseline Characteristic
Results Characteristics of the Sample Selected sociodemographic characteristics of the 102 patients at entry into the study are summarized in Table 1. Patients ranged in age from 40 to 89 years (mean age, 69 years). Both the intervention and control groups included more women than men, but gender distribution was similar in the two groups (P = 0.08). The two groups did not differ regarding race and education (P = 0.06 and P > 0.2, respectively). More people in the intervention group were married (P = 0.03). The average height by group was 163 ± 11 cm for patients in the walking program and 159 ± 9 cm for controls. The mean body weight was 77 ± 15 kg for the walking group and 76 ± 19 kg for the control group. No statistical difference was found between groups in the prevalence of major comorbid conditions or in patients' self-reported medication use in the management of any condition. The mean duration since diagnosis of osteoarthritis was 12 ± 12 years for the walking group and 11 ± 11 years for the control group. Eighteen patients in the walking program and 29 patients in the control group had unilateral (left or right) joint involvement, and 34 patients in the walking program and 21 patients in the control group had bilateral joint involvement. Compliance Forty-seven patients in the intervention group completed the 8-week walking program and were retested; 45 patients in the control group were also retested at the conclusion of the study. The average number of program sessions attended by patients assigned to the intervention group was 21 ± 6 sessions (range, 3 to 28 sessions); some patients attended more than three sessions per week. Post-test data were thus obtained for 92 of the 102 patients initially recruited to the study within the corresponding study period, except for 2 of the controls from the first program cycle.
Attrition Ten patients dropped out of the study. Of the five withdrawals in the intervention group, one was arthritisrelated (that is, the patient underwent a total knee replacement) and four were non-arthritis-related (one patient died of a cause judged to be unrelated to the intervention, one had a hip fracture due to a fall during a program session, one feared that walking might exacerbate a heart condition, and one reported family problems). Of the five withdrawals in the control group, one was due to a fractured hip after a fall and four were non-arthritis-related (one patient had a sprained ankle, one had a dental problem, and two had family problems).
Intervention Group (n - 52)
Control Group (n = 50)
Mean age*, y 70.38 ± 9 . 1 1 68.48 ± 1 1 . 3 2 Sex, n 12 Male 5 Female 40 45 Race, n Black 7 1 Hispanic 1 2 41 White 50 Marital status, n Married 18 5 Unmarried 34 45 Education, n 22 20 College graduate 10 < 4 years college 15 High school graduate 13 11 < 11th grade 5 6
P Valuet >0.2 0.08 0.06
0.03 >0.2
* Mean is given ± SD. t All P values are for comparisons between the intervention and control groups.
Outcomes Baseline and post-intervention measurements are summarized in Table 2. After the intervention, the walking distance in the experimental group increased an average of 70 meters from a baseline of 381 ± 114 meters, which represents an 18.4% increase in distance walked (CI, 9.8% to 27.0%). In contrast, the mean distance walked in 6 minutes by control patients decreased an average of 17 meters from a baseline of 356 ± 130 meters (P < 0.001). Male patients in the experimental group walked, on average, 73 meters farther than female patients at the post-test assessment; in the control group, men walked, on average, 31 meters farther than women. There were no between-subject differences in the walking distances of either male or female patients (P = 0.02). Furthermore, the difference due to gender did not vary according to the study group (P > 0.02). The effect of unilateral as opposed to bilateral joint involvement was also analyzed; differences were not significant (P > 0.2). Similarly, analysis of marital status revealed no statistically different effect on walking distance (P = 0.07). On the AIMS physical activity subscale, virtually no change from baseline was detected in the control group, but the intervention group demonstrated an average improvement of 2.41 units from an average baseline score of 6.15 ± 2.27 units (P < 0.001), which represents an improvement of 39% (CI, 15.6% to 60.4%). Scores on the AIMS arthritis impact subscale improved an average of 1.70 units from an average baseline score of 4.56 units in the intervention group and an average of 0.79 units from a baseline score of 3.85 units in the control group (P = 0.093). Scores on the AIMS arthritis pain subscale improved an average of 1.38 units from an average baseline score of 5.15 ± 1.99 units in the intervention group but only 0.10 units from the baseline score of 4.87 ± 2.31 units in the control group (P — 0.003). The change from baseline in the interven-
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Table 2. Outcome Measures at Baseline and after the Intervention* Measure
Baseline
6-minute walk, m AIMS subscales Physical activity Arthritis impact Arthritis pain Medications use
Post-Intervention Control Intervention Group Group (n = 47) (PI = 45)
P Valuet
339 ± 125
< 0.001
Intervention Group (n = 47)
Control Group (n = 45)
381 ± 114
356 ± 130
451 ± 118
5.72 3.85 4.87 2.64
3.74 2.86 3.77 3.64
6.15 4.56 5.15 2.80
± ± ± ±
2.27 2.14 1.99 1.65
± ± ± ±
2.49 2.38 2.31 1.68
± ± ± ±
2.69 1.88 1.73 1.92
5.96 3.06 4.77 2.90
± ± ± ±
2.32 1.91 2.12 2.02
< 0.001 0.093 0.003 0.08
* All 47 intervention patients completed baseline and post-intervention testing and had paired values for all five outcome measures. However, post-intervention values for all measures were obtained for only 44 of the 45 control patients; one control subject did not have paired values for the walk test. For the AIMS physical activity and arthritis impact subscales, scores are standardized on a range from 0 to 10 units, with higher scores representing greater disability and poorer health status. The AIMS arthritis pain subscale is scored 0 to 10, with higher scores representing greater pain. The AIMS medication subscale is scored from 0 to 6, with higher scores representing less frequent medication use. AIMS = Arthritis Impact Measurement Scale. t P values are for between-group comparisons regarding the differences in pretest to post-test changes.
tion group represents an improvement of 27% (CI, 9.6% to 41.4%). Scores on the AIMS medication use subscale have a different directionality from the other subscales (that is, higher scores reflect the use of less medication and lower scores reflect the use of more medication). The scores on this measure improved an average of 0.84 units from a baseline of 2.80 ± 1.65 units in the intervention group but only 0.26 units from a baseline score of 2.64 ± 1.68 units in the control group (P = 0.08). Discussion Evidence from recent epidemiologic studies (14-19) has demonstrated the overall beneficial health effects of physical activity in general and in patients with arthritis in particular (20-24). Minor and colleagues (21, 22), for example, have demonstrated that patients with osteoarthritis and rheumatoid arthritis are significantly deconditioned when compared with healthy age- and sexmatched controls. Although such patients have poor aerobic fitness because of both the disease and inactivity* several studies have indicated that participation in a low-impact exercise program (for example, swimming, bicycling, or walking) can improve aerobic fitness without adverse effects on the joints (21-23, 25-32). However, although these studies have suggested that patients with osteoarthritis show improvement in stamina, strength, and the ability to do housework or to engage in social activity, as well as reductions in joint pain, after participation in physical activity, these studies have not been definitive because of methodologic limitations and small sample sizes. Walking has been recommended as a gradual, safe, and effective form of physical activity for improving aerobic fitness in people who have a low tolerance for exercise because of illness (33). Although walking protocols used for healthy persons have involved as many as 20 weeks of training, some studies have demonstrated that aerobic fitness may be improved by as much as 15% to 30% after only 3 weeks of training (33-36). For example, among a small sample both of patients with osteoarthritis and of patients with rheumatoid arthritis, Price and colleagues (37) showed that walking safely and effectively produced significant in532
creases in aerobic fitness without triggering symptomatic flares. After a 12-week program of supervised indoor walking, patients demonstrated a 20% improvement in mean maximal oxygen consumption and an 8% increase in the mean distance walked in a brisk 5-minute walk. In addition to these outcomes, several studies have demonstrated that low-level programs of walking can also produce significant psychosocial benefits, such as mood elevation and a reduction of depression and anxiety (36, 38, 39). Walking may also be helpful in improving compliance with recommendations to increase physical activity. Many studies of compliance with exercise regimens have shown that program dropout rates are related to the intensity of the exercise regimen. Evidence suggests that higher-intensity programs of physical activity are associated with higher attrition rates, whereas walking may be more easily adopted and maintained (36). Exercise as adjunct therapy is not uniformly accepted in clinical practice in the management of patients with osteoarthritis of the knee, and thus patients are frequently advised to curtail such activity. Although walking has received some study, almost all of the investigations have focused on showing the aerobic benefits of walking in such patients, rather than the effect of walking on functional status. In the absence of data on the safety and efficacy of walking to improve functional status, both physicians and their patients are often uncertain about whether walking may be safely prescribed and undertaken in the management of osteoarthritis of the knee. Our study provides empirical support for the hypothesis that a program of supervised fitness walking and supportive patient education can be an important function-enhancing intervention in the clinical management of patients with osteoarthritis of the knee. It is the single largest randomized, controlled trial yet done to assess the effect of supervised fitness walking and patient education on functional status in patients with osteoarthritis. Two methodologic limitations of our study require comment. First, the control group did not receive an equal co-intervention. In planning the study, we did
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consider bringing control patients to the hospital three times each week during the course of the 8-week intervention period in order to provide a strictly equal cointervention; however, this was simply not feasible. Instead, we decided to provide the control patients with telephone contact three times during each week of the 8-week intervention period, which we believe provided sufficient attention. Second, it was not possible to blind the physical therapist who conducted all outcome assessments as well as the intervention program for experimental subjects. Although this constitutes a limitation of the study, we do not believe that this limitation substantially compromised the validity of our results. The functional status outcome measures of the AIMS are patient self-reports and thus are relatively uninfluenced by the individual conducting the interviews. Moreover, the 6-minute test of distance walked was done according to a standardized protocol that was adhered to throughout the study and thus minimized the potential for any differential in the application of the testing procedure across groups. Despite these limitations, we believe that the results of our study of a program of supervised fitness walking and patient education are clinically relevant. These results included an improvement in distance patients were able to walk and changes in self-reported physical activity and pain on a widely used scale of arthritis-related functional status. Moreover, we believe the findings should be considered generalizable to a broad patient population because the patients recruited to participate in our study were, on average, older (average age, 69.4 years), were more frail, and had considerably more joint involvement than patients in previous studies. Also, in contrast to patients in previous studies, our patients were not newly diagnosed with osteoarthritis. In our study, walking did not appear to worsen pain or exacerbate arthritis-related symptoms, a key consideration for both patients and clinicians. However, the fact that one patient (a 70-year-old woman) who was participating in the walking program fell and fractured a hip during one of the supervised sessions (requiring subsequent surgical repair) must be taken into consideration when assessing the overall benefits and costs of this intervention. However, one control patient also suffered a fall-related hip fracture during the study period, suggesting that this group is at risk for such an adverse event. Consequently, the risk for falling must be assessed and balanced with the potential benefits of supervised fitness walking when considering frail elderly patients for such a program. An index of the risk for falling that was developed by Tinetti and colleagues (40) can be useful in identifying potentially high-risk patients and should be used in screening older patients before enrollment in any walking program. Finally, it is important to point out that the effect on the outcome variables of interest in this study was achieved as a result of the combined effect of both supervised fitness walking and the psychosocial benefits associated with patient education and social support. Although our study was not designed to examine the differential contributions or additive effects of the multiple components of this intervention, it is possible that walking alone would not have produced the same im-
provement in outcomes that we observed. Other studies have shown the beneficial effect of psychosocial interventions and especially of social support in patients with arthritis (41, 42) and other diseases (43), and therefore the importance of the psychosocial benefit derived from the educational portion and the supportive group format of the intervention program should not be underestimated. In conclusion, our results show a strong and what we judge to be a clinically significant effect of supervised fitness walking and patient education on independent measures of the functional status of patients with osteoarthritis of the knee; this effect was achieved without exacerbating pain or triggering flares. Our results are consistent with the findings from previous studies that have demonstrated the aerobic benefits of walking in patient populations whose physical capacity has been significantly degraded by chronic joint disease. Our findings provide compelling evidence of a potentially valuable role for supervised fitness walking and supportive patient education in the management of patients with osteoarthritis. We are currently assessing the longterm outcome of this intervention in a follow-up study of these patients. This trial was limited to patients with osteoarthritis of the lower extremities, and the utility of such a program for patients with other chronic arthritic conditions (for example, degenerative joint disease of the hip and lower back) warrants further investigation. Acknowledgments: The authors thank the patients and physicians who agreed to participate in the study; Kate Lorig, RN, DrPH, of the Stanford Arthritis Center and Marian Minor, PT, PhD, of the University of Missouri who provided helpful insights during the early stages of planning the study; Mark Kasper, MS, and Jeanne Marie Cioppa-Mosca, PT, MBA, who assisted in collecting data; Stephen Paget, MD, who facilitated patient recruitment; Louis L. Harris, MS, PT, the late Michael Kroll, MA, PT, Marita Murrman, RN, MS, and Yvonne Webbe, RD, MS, who provided supportive assistance throughout the study; James C. Otis, PhD, and Sherry Backus, PT, who assisted in conducting gait analyses; and members of the Cornell Arthritis Center's Research Methodology Core who contributed helpful comments on earlier drafts of the paper. Grant Support: In part by a dissertation research grant to Dr. Kovar from the Arthritis Foundation and by National Institutes of Health Multipurpose Arthritis Center Program Grant No. 1 P60 AR38520-01A1 from the National Institute for Arthritis and Musculoskeletal and Skin Diseases. Requests for Reprints: John P. Allegrante, PhD, Cornell Arthritis and Musculoskeletal Diseases Center, The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. Current Author Addresses: Drs. Kovar, Allegrante, MacKenzie, Peterson, and Charlson: The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. Dr. Gutin: Department of Pediatrics and Georgia Prevention Institute, Medical College of Georgia, Augusta GA 30912-3710.
References 1. Moscowitz RW, Haug MR, eds. Arthritis and the Elderly. New York: Springer; 1986. 2. Moscowitz RW. Primary osteoarthritis: epidemiology, clinical aspects, and general management. Am J Med. 1987;83(Suppl 5A):5-10. 3. Felson DT, Anderson J J, Naimark A, Walker AM, Meenan RF. Obesity and knee osteoarthritis. The Framingham Study. Ann Intern Med. 1988;109:18-24. 4. Felson DT, Naimark A, Anderson J, Kazis L, Castelli W, Meenan RF. The prevalence of knee osteoarthritis in the elderly: The Framingham Osteoarthritis Study. Arthritis Rheum. 1987;30:914-8. 5. Felson DT. Epidemiology of hip and knee osteoarthritis. Epidemiol Rev. 1988;10:1-28. 6. van Saase J, van Romunde LK, Cats A, Vandenbroucke J P , Valkenburg HA. Epidemiology of osteoarthritis: Zoetermeer survey.
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