Functional Impairment and Hospital Readmission in Medicare Seniors

IMPORTANCE: Medicare currently penalizes hospitals for high readmission rates for seniors but does not account for common age-related syndromes, such as functional impairment. OBJECTIVE: To assess the effects of functional impairment on Medicare hospital readmissions given the high prevalence of functional impairments in community-dwelling seniors. DESIGN, SETTING, AND PARTICIPANTS: We created a nationally representative cohort of 7854 community-dwelling seniors in the Health and Retirement Study, with 22,289 Medicare hospitalizations from January 1, 2000, through December 31, 2010. MAIN OUTCOMES AND MEASURES: Outcome was 30-day readmission assessed by Medicare claims. The main predictor was functional impairment determined from the Health and Retirement Study interview preceding hospitalization, stratified into the following 5 levels: no functional impairments, difficulty with 1 or more instrumental activities of daily living, difficulty with 1 or more activities of daily living (ADL), dependency (need for help) in 1 to 2 ADLs, and dependency in 3 or more ADLs. Adjustment variables included age, race/ethnicity, sex, annual income, net worth, comorbid conditions (Elixhauser score from Medicare claims), and prior admission. We performed multivariable logistic regression to adjust for clustering at the patient level to characterize the association of functional impairments and readmission. RESULTS: Patients had a mean (SD) age of 78.5 (7.7) years (range, 65-105 years); 58.4% were female, 84.9% were white, 89.6% reported 3 or more comorbidities, and 86.0% had 1 or more hospitalizations in the previous year. Overall, 48.3% had some level of functional impairment before admission, and 15.5% of hospitalizations were followed by readmission within 30 days. We found a progressive increase in the adjusted risk of readmission as the degree of functional impairment increased: 13.5% with no functional impairment, 14.3% with difficulty with 1 or more instrumental activities of daily living (odds ratio OR, 1.06; 95% CI, 0.94-1.20), 14.4% with difficulty with 1 or more ADL (OR, 1.08; 95% CI, 0.96-1.21), 16.5% with dependency in 1 to 2 ADLs (OR, 1.26; 95% CI, 1.11-1.44), and 18.2% with dependency in 3 or more ADLs (OR, 1.42; 95% CI, 1.20-1.69). Subanalysis restricted to patients admitted with conditions targeted by Medicare (ie, heart failure, myocardial infarction, and pneumonia) revealed a parallel trend with larger effects for the most impaired (16.9% readmission rate for no impairment vs 25.7% for dependency in 3 or more ADLs OR, 1.70; 95% CI, 1.04-2.78). CONCLUSIONS AND RELEVANCE: Functional impairment is associated with increased risk of 30-day all-cause hospital readmission in Medicare seniors, especially those admitted for heart failure, myocardial infarction, or pneumonia. Functional impairment may be an important but underaddressed factor in preventing readmissions for Medicare seniors.