Association of housing adaptation services with the prevention of care needs level deterioration for older adults with frailty in Japan: a retrospective cohort study

Background Housing adaptations are aimed at minimizing the mismatch between older adults’ functional limitations and their building environments. We examined the association of housing adaptations with the prevention of care needs level deterioration among older adults with frailty in Japan. Methods The subjects comprised individuals who were first certified as having care support levels (defined as frail, the lowest two of seven care needs levels) under the public long-term care insurance systems between April 2015 and September 2016 from a municipality close to Tokyo. The implementation of housing adaptations was evaluated in the first six months of care support certification. Survival analysis with Cox proportional hazards model was performed to examine the association between housing adaptations and at least one care needs level deterioration, adjusting for age, sex, household income level, certified care support levels, cognitive function, instrumental activities of daily living, and the utilization of preventive care services (designed not to progress disabilities). We further examined the differences in the association of the housing adaptation amount by categorizing the subjects into the maximum cost group (USD 1,345–1,513) or not the maximum cost group (< USD 1,345). All the subjects were followed until the earliest of deterioration in care needs level, deaths, moving out of the municipality, or March 2018. Results Among 796 older adults, 283 (35.6%) implemented housing adaptations. The incidence of care needs level deterioration was 19.3/1000 person-month of older adults who implemented housing adaptations, whereas 31.9/1000 person-month of those who did not. The adjusted hazard ratio (aHR) of care needs level deterioration was 0.69 (95% confidence interval (CI): 0.51–0.93). The aHRs were 0.51 (95% CI: 0.31–0.82) and 0.78 (95% CI: 0.57–1.07) in the maximum and not maximum cost groups, respectively. Conclusions Housing adaptations may prevent care needs level deterioration of older adults with frailty. Policymakers and health professionals should deliver housing adaptations for older adults at risk of increasing care needs.