Association Between Activities of Daily Living and Mortality Among Institutionalized Elderly Adults in Japan

Background: We assessed the association between activities of daily living (ADL) and mortality among nursing home residents in Japan. Methods: This I-year prospective cohort study investigated 8902 elderly adults in 140 nursing homes. Baseline measurements included age, sex, height, weight, body mass index (BMI), ADL, and dementia level. ADL levels were obtained by caregivers, using the Barthel Index (BI), after which total BI scores were calculated (higher scores indicate less dependence). Information on dates of discharge and mortality was also obtained to calculate person-years. The Cox proportional hazards model was used to estimate hazard ratios (HRs). Results: Mean age was 84.3 years, and mean total BI score was 38.5. The HRs of mortality adjusted for sex, age, BM I, and type of nursing home were 7.6 (95% CI: 3.3-17.8) for those with a BI score of 0 (totally dependent), 3.9 (1.7-9.0) for those with a score of 1 to 10, 3.5 (1.4-8.7) for those with a score of 11 to 40, 2.7 (1.4-5.1) for those with a score of 41 to 70, and 1.3 (0.7-2.4) for those with a score of 71 to 99 (P for trend <0.001), as compared with those with a score of 100. Multivariate analysis revealed that BI, sex, age, and BMI were significantly associated with mortality rate. Conclusions: There was a clear inverse association between ADL level and mortality. In conjunction with other risk factors, ADL level might effectively predict short-term mortality in institutionalized elderly adults.