Impact of tailored message notifications for frailty prevention in older adults: a quasi-randomized controlled study using a regression discontinuity design.

[Purpose] This study investigated the potential of tailored message notifications based on municipal health check-up results to improve pre-frailty and frailty in older adults. [Participants and Methods] This study was conducted in Iiyama City, Nagano Prefecture, Japan, by using the Kihon Checklist to assess the health status of older adults. Since 2019, Iiyama City has sent notifications to individuals with pre-frailty (Kihon Checklist score: 4-7) and frailty (Kihon Checklist score: ≥8). A regression discontinuity design was used to estimate the effects of the intervention by comparing the groups with scores just above and below the cutoff points. Data from 6,382 individuals aged ≥65 years from 2019 to 2022 were analyzed. [Results] The intervention slightly improved the Kihon Checklist scores in the pre-frailty group. No statistically significant effects were observed in the frailty group or after multiple imputations for missing data. [Conclusion] The findings suggest that tailored message notifications can improve frailty prevention among pre-frail older adults. However, the limited frequency and content of these messages may have reduced their effectiveness. Therefore, more frequent and targeted messages are needed to address the needs of frail individuals.