International Journal for Quality in Health Care 2014; Volume 26, Number 5: pp. 530–537 Advance Access Publication: 3 July 2014
10.1093/intqhc/mzu065
Association of weekend continuity of care with hospital length of stay SAUL BLECKER1,2, DANIEL SHINE2, NAEUN PARK1, KEITH GOLDFELD1, R. SCOTT BRAITHWAITE1,2, MARTHA J. RADFORD2 AND MARC N. GOUREVITCH1 1
Department of Population Health, New York University School of Medicine, New York, NY, USA, and 2Department of Medicine, New York University Langone Medical Center, New York, NY, USA Address reprint requests to: Saul Blecker, New York University School of Medicine, 227 E. 30th Street, 648, New York, NY 10016, USA. Tel: +1-646-501-2513; E-mail: [email protected] Accepted for publication 15 May 2014
Abstract Objective. The purpose of this study was to evaluate the association of physician continuity of care with length of stay, likelihood of weekend discharge, in-hospital mortality and 30-day readmission. Design. A cohort study of hospitalized medical patients. The primary exposure was the weekend usual provider continuity (UPC) over the initial weekend of care. This metric was adapted from an outpatient continuity of care index. Regression models were developed to determine the association between UPC and outcomes. Main outcome measure. Length of stay which was calculated as the number of days from the first Saturday of the hospitalization to the day of discharge. Results. Of the 3391 patients included in this study, the prevalence of low, moderate and high UPC for the initial weekend of hospitalization was 58.7, 22.3 and 19.1%, respectively. When compared with low continuity of care, both moderate and high continuity of care were associated with reduced length of stay, with adjusted rate ratios of 0.92 (95% CI 0.86–1.00) and 0.64 (95% CI 0.53–0.76), respectively. High continuity of care was associated with likelihood of weekend discharge (adjusted odds ratio 2.84, 95% CI 2.11–3.83) but was not significantly associated with mortality (adjusted odds ratio 0.72, 95% CI 0.29–1.80) or readmission (adjusted odds ratio 0.88, 95% CI 0.68–1.14) when compared with low continuity of care. Conclusions. Increased weekend continuity of care is associated with reduced length of stay. Improvement in weekend crosscoverage and patient handoffs may be useful to improve clinical outcomes. Keywords: hospital, continuity of care, length of stay Cross-coverage of patients in hospitals occurs when the immediate responsibility of patient care is by a physician who is not the primary responsible provider [1]. Cross-coverage is common on weekends and can lead to decreased continuity of care [2]. Continuity of care has been defined in multiple ways, broadly referring to continuity of patient information among providers, and more specifically to the ongoing relationship of a patient with one provider [3–5]. The latter definition of continuity of care, in which a single physician assumes continued responsibility for the care of an individual patient, is the one commonly used in the hospital setting [1, 4, 6–8]. In the outpatient setting, decreased continuity of care has been linked to poor outcomes, including increased hospitalizations and reduced delivery of preventive care measures [9]. Within hospitals, decreased continuity of care has been evaluated primarily among resident physicians and has been
associated with adverse events [1, 7]. For instance, one study demonstrated that resident physician cross-coverage was associated with six times the odds of preventable adverse events [1], while another suggested that decreased continuity of care related to work hour reform resulted in increased medical complications and diagnostic test delay [7]. Delays in care and adverse events related to cross-coverage may occur at the attending physician level as well; however, prior studies have been limited by concern for reverse causation [8] in which an outcome, such as increased length of stay, causes the exposure of interest, in this case increased crosscoverage. Furthermore, the effect of attending physician weekend continuity of care on clinical outcomes has not been well characterized. Continuity of care is particularly relevant on weekends, a time of frequent cross-coverage which may be associated with adverse events [10]. More generally, weekends have been
International Journal for Quality in Health Care vol. 26 no. 5 © The Author 2014. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved
530
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Setting. An academic medical center.
Hospital continuity of care • Quality management
associated with reduced quality of care and poor outcomes including in-hospital cardiac arrest and mortality, when compared with weekdays [11–14]. The primary purpose of this study was to evaluate the association between attending physician continuity of care on weekends and clinical outcomes. We hypothesized that crosscoverage by a weekend physician would be associated with increased length of stay as a result of delays in clinical decisionmaking, including diagnostic work-up and treatment. We further hypothesized that decreased attending physician continuity of care would be associated with reduced likelihood of
Weekend UPC ¼
1 weekday note prior to the first weekend of hospitalization; hospitalizations in which a primary inpatient attending physician could not be identified in this manner were excluded. As we were interested in continuity of care on weekends, we specifically defined the opportunities for clinical encounters based on those occurring during weekend days of the hospitalization, and coverage was determined by whether the primary inpatient attending physician wrote a progress note on that day. Accordingly, weekend UPC was the fraction of weekend days that a clinical note was written by the primary inpatient physician:
Weekend days with a clinical note by a primary inpatient attending physician : Total weekend days of hospitalizations
weekend discharge and increased rates of in-hospital mortality and 30-day readmission.
Methods
531
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We performed a cohort study of patients hospitalized on the Internal Medicine service at NYU Langone Medical Center between 1 January 2011 and 30 June 2012 using data derived from the hospital electronic medical record. Hospitalizations were included if they had a minimum length of stay of 2 days and included at least 1 weekend day. We excluded hospitalizations of individuals younger than 18 years. Only the first hospitalization was included for individuals with more than one admission during the period. The setting for the study was Tisch Hospital, a 705-bed urban academic medical center. During this period, providers on the Medicine service cared for ∼150–200 patients on a given day. Patients on the Medicine service were typically located on six medical wards, which included dedicated wards for cardiology and hematology/oncology patients. Attending physicians were either hospitalists, who worked exclusively with inpatients and were usually employed by the hospital, or non-hospitalists. In general during this period, covering hospitalist attending physicians attended on half of weekend days, while weekend coverage by non-hospitalist attending physicians was variable. The primary exposure was the weekend usual provider continuity (UPC) index, a measure of provider continuity of care on the weekend. Weekend UPC was based on the UPC index, a metric developed in the outpatient setting to assess the level of continuity of care [15, 16]. The outpatient UPC is calculated as the number of clinic visits made to the primary provider divided by the number of clinic visits made to all providers over a given time period; thus the UPC assesses the proportion of clinical encounters attributable to the primary provider. To adapt this published metric in the present study, the primary inpatient attending physician was defined as the discharge physician of record. To ensure the primary inpatient attending physician was on service at the time of the weekend of interest, we required the discharge attending physician to write at least
The UPC index was coded retrospectively in the present study by the study analytic team. Our analysis specifically focused on weekend UPC for the first weekend of hospitalization. This was done to minimize the danger of reverse causality: the exposure was measured at the first weekend and outcomes were assessed after this weekend. First weekend UPC was categorized as 0, 0.5 and 1 and termed low, moderate and high continuity of care, respectively. The UPC categories represented all possible values as we only considered UPC for the first weekend of service; these categories are similar to those used for the UPC index in the outpatient setting [17]. The primary outcome was truncated length of stay which was calculated as the number of days from the first Saturday of the hospitalization to the day of discharge. We defined length of stay in this manner to ensure that it was assessed only after the first weekend UPC. Secondary outcomes included weekend day of discharge (versus weekday), in-hospital mortality and 30-day hospital readmission; these secondary outcomes were all binary variables. For evaluation of 30-day readmission, we excluded individuals who died during the index hospitalization from the analysis. We captured only readmissions to our medical center. Covariates in the model included age, gender, race, insurance, admission source, hospitalist service, Charlson comorbidity score [18], admission day of the week and service intensity weight (SIW). Age was evaluated as a categorical variable and categorized as 18–39, 40–59, 60–79 and ≥80 years. Race was categorized as black, white and other. Insurance was categorized as Medicaid, self-pay or null and other. Admission source was categorized as emergency room (ER), other hospital, skilled nursing facility and home or other. Hospitalist service was a binary variable and reflected whether or not the primary attending physician was a hospitalist physician. A Charlson comorbidity index, which reflects risk related to comorbid conditions, was categorized as 0, 1, 2, 3 and ≥4 according to its distribution. SIW is a relative measure of resources needed for a given All Patient Refined Diagnosis Related Group in New York State [19]. SIW was categorized as 0–0.9, 1–1.9, 2–2.9, 3–5.9 and ≥6 in accordance with its distribution [20].
Blecker et al.
Statistical analysis
Results Of the 3391 hospitalizations on the Internal Medicine service that were included in this study, the majority (82.5%) included only one weekend. As seen in Fig. 1, over half of the hospitalizations had a cross-covering physician caring for the patient over the first weekend, while 22.3% of hospitalizations experienced moderate continuity of care and the remaining 19.1% of hospitalizations experienced high continuity of care during the first weekend. Patient demographic characteristics were similar among first weekend UPC groups. Individuals with moderate continuity of care were more likely to be admitted from the ER and were more likely to be covered by a hospitalist physician when compared with the other groups (Table 1). The specialty of the primary attending physician was most commonly in general internal medicine (36.7%), followed by cardiology
532
Figure 1 Distribution of UPC for 3391 hospitalizations, 2011–12. The distribution reflects the UPC index for the first weekend of hospitalization. (18.7%), hematology/oncology (13.5%) and pulmonology (10.3%). Increased continuity of care, as measured by the first weekend UPC, was associated with decreased length of stay in a stepwise fashion (Table 2). These findings were sustained after multivariate adjustment: when compared with low continuity of care, moderate continuity of care was associated with an 8% (95% CI 0.3–14%) reduction in length of stay while high continuity of care with a 36% (95% CI 24–37%) reduction in length of stay (Table 3). Increased continuity of care was also associated with an increased likelihood of weekend discharge; the odds ratio for weekend discharge was 2.84 (95% CI 2.11–3.83) for patients with high continuity of care when compared with patients with low continuity of care. In unadjusted analysis, increased continuity of care was significantly associated with decreased mortality. However, no association between weekend UPC and mortality was observed after multivariate adjustment (Table 3). Findings were similar when we used hierarchical regression models. Subgroups of heart failure (n = 246) and pneumonia (n = 178) hospitalizations had associations between first weekend UPC and length of stay that were similar to the overall cohort (adjusted rate ratio of 0.78 (95% CI 0.51–1.19) and 0.49 (95% CI 0.30–0.78) for high versus low continuity of care, respectively). Among these subgroups, the relationships between first weekend UPC index and other outcomes were difficult to interpret due to small sample size (Appendix Tables A1 and A2). The associations between continuity of care and clinical outcomes were similar for hospitalizations with the length of stay ≤14 days when compared with the overall cohort (Appendix Table A3).
Discussion In this study, we found cross-coverage to be common among attending physicians on weekends. Decreased continuity of care by attending physicians on the weekend was associated
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Baseline characteristics of admissions in each of the first weekend UPC categories of low, moderate and high continuity of care were compared using χ 2 tests for categorical variables and ANOVA for continuous variables. The association between weekend UPC category and length of stay was estimated using an unadjusted negative binomial regression model. We developed a generalized estimating equation (GEE) regression model [21] with a negative binomial distribution to adjust for covariates and to account for clustering by physician. In this model, the dependent variable was study length of stay and the primary independent variable was weekend UPC category. Covariates in the model included age, gender, race, insurance, admission source, hospitalist service, Charlson index, admission day and SIW. Three GEE regression models with binomial distributions were developed with weekend UPC category as the primary independent variable and the dependent variable as either weekend discharge, mortality or 30-day readmission; these models were used to estimate the strength of the association of weekend UPC with these outcomes after adjusting for the covariates listed above. We performed a sensitivity analysis in which we used mixed effects models to determine the association between weekend UPC and outcomes. We performed three subgroup analyses to examine the association between first weekend UPC categories and outcomes among more homogeneous groups than that of the overall analysis. We examined this association among hospitalized patients with two common medical conditions: heart failure ( principal International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes of 402.01, 402.11, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, 404.93 and 428) [22] and pneumonia (ICD-9 codes of 481, 482, 483, 485 and 486) [23]. To minimize the influence of outliers, we performed a third subgroup analysis of hospitalizations with the length of stay of
10.1093/intqhc/mzu065
Association of weekend continuity of care with hospital length of stay SAUL BLECKER1,2, DANIEL SHINE2, NAEUN PARK1, KEITH GOLDFELD1, R. SCOTT BRAITHWAITE1,2, MARTHA J. RADFORD2 AND MARC N. GOUREVITCH1 1
Department of Population Health, New York University School of Medicine, New York, NY, USA, and 2Department of Medicine, New York University Langone Medical Center, New York, NY, USA Address reprint requests to: Saul Blecker, New York University School of Medicine, 227 E. 30th Street, 648, New York, NY 10016, USA. Tel: +1-646-501-2513; E-mail: [email protected] Accepted for publication 15 May 2014
Abstract Objective. The purpose of this study was to evaluate the association of physician continuity of care with length of stay, likelihood of weekend discharge, in-hospital mortality and 30-day readmission. Design. A cohort study of hospitalized medical patients. The primary exposure was the weekend usual provider continuity (UPC) over the initial weekend of care. This metric was adapted from an outpatient continuity of care index. Regression models were developed to determine the association between UPC and outcomes. Main outcome measure. Length of stay which was calculated as the number of days from the first Saturday of the hospitalization to the day of discharge. Results. Of the 3391 patients included in this study, the prevalence of low, moderate and high UPC for the initial weekend of hospitalization was 58.7, 22.3 and 19.1%, respectively. When compared with low continuity of care, both moderate and high continuity of care were associated with reduced length of stay, with adjusted rate ratios of 0.92 (95% CI 0.86–1.00) and 0.64 (95% CI 0.53–0.76), respectively. High continuity of care was associated with likelihood of weekend discharge (adjusted odds ratio 2.84, 95% CI 2.11–3.83) but was not significantly associated with mortality (adjusted odds ratio 0.72, 95% CI 0.29–1.80) or readmission (adjusted odds ratio 0.88, 95% CI 0.68–1.14) when compared with low continuity of care. Conclusions. Increased weekend continuity of care is associated with reduced length of stay. Improvement in weekend crosscoverage and patient handoffs may be useful to improve clinical outcomes. Keywords: hospital, continuity of care, length of stay Cross-coverage of patients in hospitals occurs when the immediate responsibility of patient care is by a physician who is not the primary responsible provider [1]. Cross-coverage is common on weekends and can lead to decreased continuity of care [2]. Continuity of care has been defined in multiple ways, broadly referring to continuity of patient information among providers, and more specifically to the ongoing relationship of a patient with one provider [3–5]. The latter definition of continuity of care, in which a single physician assumes continued responsibility for the care of an individual patient, is the one commonly used in the hospital setting [1, 4, 6–8]. In the outpatient setting, decreased continuity of care has been linked to poor outcomes, including increased hospitalizations and reduced delivery of preventive care measures [9]. Within hospitals, decreased continuity of care has been evaluated primarily among resident physicians and has been
associated with adverse events [1, 7]. For instance, one study demonstrated that resident physician cross-coverage was associated with six times the odds of preventable adverse events [1], while another suggested that decreased continuity of care related to work hour reform resulted in increased medical complications and diagnostic test delay [7]. Delays in care and adverse events related to cross-coverage may occur at the attending physician level as well; however, prior studies have been limited by concern for reverse causation [8] in which an outcome, such as increased length of stay, causes the exposure of interest, in this case increased crosscoverage. Furthermore, the effect of attending physician weekend continuity of care on clinical outcomes has not been well characterized. Continuity of care is particularly relevant on weekends, a time of frequent cross-coverage which may be associated with adverse events [10]. More generally, weekends have been
International Journal for Quality in Health Care vol. 26 no. 5 © The Author 2014. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved
530
Downloaded from by guest on July 6, 2015
Setting. An academic medical center.
Hospital continuity of care • Quality management
associated with reduced quality of care and poor outcomes including in-hospital cardiac arrest and mortality, when compared with weekdays [11–14]. The primary purpose of this study was to evaluate the association between attending physician continuity of care on weekends and clinical outcomes. We hypothesized that crosscoverage by a weekend physician would be associated with increased length of stay as a result of delays in clinical decisionmaking, including diagnostic work-up and treatment. We further hypothesized that decreased attending physician continuity of care would be associated with reduced likelihood of
Weekend UPC ¼
1 weekday note prior to the first weekend of hospitalization; hospitalizations in which a primary inpatient attending physician could not be identified in this manner were excluded. As we were interested in continuity of care on weekends, we specifically defined the opportunities for clinical encounters based on those occurring during weekend days of the hospitalization, and coverage was determined by whether the primary inpatient attending physician wrote a progress note on that day. Accordingly, weekend UPC was the fraction of weekend days that a clinical note was written by the primary inpatient physician:
Weekend days with a clinical note by a primary inpatient attending physician : Total weekend days of hospitalizations
weekend discharge and increased rates of in-hospital mortality and 30-day readmission.
Methods
531
Downloaded from by guest on July 6, 2015
We performed a cohort study of patients hospitalized on the Internal Medicine service at NYU Langone Medical Center between 1 January 2011 and 30 June 2012 using data derived from the hospital electronic medical record. Hospitalizations were included if they had a minimum length of stay of 2 days and included at least 1 weekend day. We excluded hospitalizations of individuals younger than 18 years. Only the first hospitalization was included for individuals with more than one admission during the period. The setting for the study was Tisch Hospital, a 705-bed urban academic medical center. During this period, providers on the Medicine service cared for ∼150–200 patients on a given day. Patients on the Medicine service were typically located on six medical wards, which included dedicated wards for cardiology and hematology/oncology patients. Attending physicians were either hospitalists, who worked exclusively with inpatients and were usually employed by the hospital, or non-hospitalists. In general during this period, covering hospitalist attending physicians attended on half of weekend days, while weekend coverage by non-hospitalist attending physicians was variable. The primary exposure was the weekend usual provider continuity (UPC) index, a measure of provider continuity of care on the weekend. Weekend UPC was based on the UPC index, a metric developed in the outpatient setting to assess the level of continuity of care [15, 16]. The outpatient UPC is calculated as the number of clinic visits made to the primary provider divided by the number of clinic visits made to all providers over a given time period; thus the UPC assesses the proportion of clinical encounters attributable to the primary provider. To adapt this published metric in the present study, the primary inpatient attending physician was defined as the discharge physician of record. To ensure the primary inpatient attending physician was on service at the time of the weekend of interest, we required the discharge attending physician to write at least
The UPC index was coded retrospectively in the present study by the study analytic team. Our analysis specifically focused on weekend UPC for the first weekend of hospitalization. This was done to minimize the danger of reverse causality: the exposure was measured at the first weekend and outcomes were assessed after this weekend. First weekend UPC was categorized as 0, 0.5 and 1 and termed low, moderate and high continuity of care, respectively. The UPC categories represented all possible values as we only considered UPC for the first weekend of service; these categories are similar to those used for the UPC index in the outpatient setting [17]. The primary outcome was truncated length of stay which was calculated as the number of days from the first Saturday of the hospitalization to the day of discharge. We defined length of stay in this manner to ensure that it was assessed only after the first weekend UPC. Secondary outcomes included weekend day of discharge (versus weekday), in-hospital mortality and 30-day hospital readmission; these secondary outcomes were all binary variables. For evaluation of 30-day readmission, we excluded individuals who died during the index hospitalization from the analysis. We captured only readmissions to our medical center. Covariates in the model included age, gender, race, insurance, admission source, hospitalist service, Charlson comorbidity score [18], admission day of the week and service intensity weight (SIW). Age was evaluated as a categorical variable and categorized as 18–39, 40–59, 60–79 and ≥80 years. Race was categorized as black, white and other. Insurance was categorized as Medicaid, self-pay or null and other. Admission source was categorized as emergency room (ER), other hospital, skilled nursing facility and home or other. Hospitalist service was a binary variable and reflected whether or not the primary attending physician was a hospitalist physician. A Charlson comorbidity index, which reflects risk related to comorbid conditions, was categorized as 0, 1, 2, 3 and ≥4 according to its distribution. SIW is a relative measure of resources needed for a given All Patient Refined Diagnosis Related Group in New York State [19]. SIW was categorized as 0–0.9, 1–1.9, 2–2.9, 3–5.9 and ≥6 in accordance with its distribution [20].
Blecker et al.
Statistical analysis
Results Of the 3391 hospitalizations on the Internal Medicine service that were included in this study, the majority (82.5%) included only one weekend. As seen in Fig. 1, over half of the hospitalizations had a cross-covering physician caring for the patient over the first weekend, while 22.3% of hospitalizations experienced moderate continuity of care and the remaining 19.1% of hospitalizations experienced high continuity of care during the first weekend. Patient demographic characteristics were similar among first weekend UPC groups. Individuals with moderate continuity of care were more likely to be admitted from the ER and were more likely to be covered by a hospitalist physician when compared with the other groups (Table 1). The specialty of the primary attending physician was most commonly in general internal medicine (36.7%), followed by cardiology
532
Figure 1 Distribution of UPC for 3391 hospitalizations, 2011–12. The distribution reflects the UPC index for the first weekend of hospitalization. (18.7%), hematology/oncology (13.5%) and pulmonology (10.3%). Increased continuity of care, as measured by the first weekend UPC, was associated with decreased length of stay in a stepwise fashion (Table 2). These findings were sustained after multivariate adjustment: when compared with low continuity of care, moderate continuity of care was associated with an 8% (95% CI 0.3–14%) reduction in length of stay while high continuity of care with a 36% (95% CI 24–37%) reduction in length of stay (Table 3). Increased continuity of care was also associated with an increased likelihood of weekend discharge; the odds ratio for weekend discharge was 2.84 (95% CI 2.11–3.83) for patients with high continuity of care when compared with patients with low continuity of care. In unadjusted analysis, increased continuity of care was significantly associated with decreased mortality. However, no association between weekend UPC and mortality was observed after multivariate adjustment (Table 3). Findings were similar when we used hierarchical regression models. Subgroups of heart failure (n = 246) and pneumonia (n = 178) hospitalizations had associations between first weekend UPC and length of stay that were similar to the overall cohort (adjusted rate ratio of 0.78 (95% CI 0.51–1.19) and 0.49 (95% CI 0.30–0.78) for high versus low continuity of care, respectively). Among these subgroups, the relationships between first weekend UPC index and other outcomes were difficult to interpret due to small sample size (Appendix Tables A1 and A2). The associations between continuity of care and clinical outcomes were similar for hospitalizations with the length of stay ≤14 days when compared with the overall cohort (Appendix Table A3).
Discussion In this study, we found cross-coverage to be common among attending physicians on weekends. Decreased continuity of care by attending physicians on the weekend was associated
Downloaded from by guest on July 6, 2015
Baseline characteristics of admissions in each of the first weekend UPC categories of low, moderate and high continuity of care were compared using χ 2 tests for categorical variables and ANOVA for continuous variables. The association between weekend UPC category and length of stay was estimated using an unadjusted negative binomial regression model. We developed a generalized estimating equation (GEE) regression model [21] with a negative binomial distribution to adjust for covariates and to account for clustering by physician. In this model, the dependent variable was study length of stay and the primary independent variable was weekend UPC category. Covariates in the model included age, gender, race, insurance, admission source, hospitalist service, Charlson index, admission day and SIW. Three GEE regression models with binomial distributions were developed with weekend UPC category as the primary independent variable and the dependent variable as either weekend discharge, mortality or 30-day readmission; these models were used to estimate the strength of the association of weekend UPC with these outcomes after adjusting for the covariates listed above. We performed a sensitivity analysis in which we used mixed effects models to determine the association between weekend UPC and outcomes. We performed three subgroup analyses to examine the association between first weekend UPC categories and outcomes among more homogeneous groups than that of the overall analysis. We examined this association among hospitalized patients with two common medical conditions: heart failure ( principal International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes of 402.01, 402.11, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, 404.93 and 428) [22] and pneumonia (ICD-9 codes of 481, 482, 483, 485 and 486) [23]. To minimize the influence of outliers, we performed a third subgroup analysis of hospitalizations with the length of stay of
