Complement, Not Substitute: How Adult Day Services Support Informal Caregivers to Reduce Nursing Home Admissions...

In January 2018, South Korea introduced the cognitive support grade (CSG) within its long-term care insurance (LTCI) system, expanding eligibility for adult day services (ADS) to older adults with mild dementia. This study evaluates the policy's impact on reducing institutional care use and public expenditure using national claims data.

This study employed an interrupted time series (ITS) design to evaluate the population-level impact of the 2018 policy reform using monthly aggregated data between January 2015 and December 2018. To explore heterogeneity in policy effects, subgroup analyses were conducted using various characteristics.

Following the policy reform, the share of population with ADS eligibility increased by 54.0 percentage points (95% CI: 49.6 to 58.4), followed by a 6.66-day rise in actual ADS uptake (95% CI: 5.11 to 8.21) and a 2.22-day reduction in institutional care use (95% CI: -4.03 to -0.412). Total public insurer costs remained unchanged, as reduced institutional care expenditures were largely offset by increased HCBS costs. Subgroup analyses suggested that ADS was most effective among individuals with coexisting informal care support.

The findings suggest that ADS may function as a complement to-rather than a substitute for-informal care and is associated with reduced institutionalization risk. Optimizing ADS delivery to match caregiving capacity may further enhance effectiveness.