Association of frailty screening–based preventive care with long-term care certification rates among Japanese people aged 75 years and older: an interrupted time-series analysis
Shunsuke Soma, Sho Sasaki, Sumie Sakamoto, Ryoko Higa, Ryohei Yamamoto, Hiroaki Nakagawa, Hajime Yamazaki, Sugihiro Hamaguchi, Shunichi FukuharaAbstract
Background
In rapidly ageing societies, promoting healthy ageing is essential. Japan launched a nationwide policy using questionnaire-based frailty screening to help older adults recognise their risk and engage in preventive care. This study evaluated whether this policy was associated with changes in long-term care (LTC) need.
Methods
The intervention was a health guidance programme initiated through frailty screening and delivered at the municipal level from April 2022. We conducted this single-city study in Sukagawa City, Japan. We extracted monthly data on LTC certifications and population from January 2015 to December 2025. We analysed these data using an interrupted time-series design with segmented regression. The outcome was the monthly age-standardised LTC certification rate among adults aged ≥75 years. We assumed a slope change occurring 12 months after the intervention and fitted Poisson regression models with a log link and an offset for population.
Results
Following the intervention, the trend in the LTC certification rate among adults aged ≥75 years declined relative to the pre-intervention trend (annualised RR for the change in trend, 0.974; 95% CI, 0.963–0.983). At the end of follow-up, the model-estimated age-standardised LTC certification rate was 6.8% lower than the counterfactual rate projected from continuation of the pre-intervention trend (95% CI, 4.4%–10.0%).
Conclusion
The frailty screening–based preventive care initiative for older adults was associated with a reduction in LTC certification rates. These findings suggest the potential value of linking frailty screening with broad preventive guidance as a municipal approach to addressing population-level LTC need.