Influence of co-existing social isolation and homebound status on medical care utilization and expenditure among older adults in Japan

OBJECTIVE: To examine whether co-existing social isolation and homebound status influence medical care utilization and expenditure in older adults. METHODS: Postal surveys on social isolation and homebound status were performed on older adults aged ≥65 years residing in a Japanese suburban city. Information on medical care utilization and expenditure was obtained from insurance claims data. These outcomes were examined over a three-year period (December 2008 to November 2011) for all participants (Analysis I, n = 1386) and during the last year of life for mortality cases (Analysis II, n = 107). A two-part model was used to analyze the influence of social isolation and homebound status on medical care utilization (first model: logistic regression model) and its related expenditure (second model: generalized linear model). RESULTS: Almost 12 % of participants were both socially isolated and homebound. Analysis I showed that these participants were significantly less likely to use outpatient and home medical care than participants with neither characteristic (odds ratio: 0.536, 95 % confidence interval: 0.303−0.948). However, Analysis II showed that participants with both characteristics had significantly higher daily outpatient and home medical expenditure in the year before death than participants with neither characteristic (risk ratio: 2.155, 95 % confidence interval: 1.338−3.470). DISCUSSION: Older adults who are both socially isolated and homebound are less likely to regularly utilize medical care, which may eventually lead to serious health problems that require more intensive treatment. Measures are needed to encourage the appropriate use of medical care in these individuals to effectively manage any existing conditions.