[Process and outcome evaluation of community-based strategies for frailty prevention in the elderly with the help of the senior workforce at Silver Human Resources Centers in Yabu City, Japan].

: Objectives　Preventing frailty is a crucial issue in aging societies such as Japan. In 2011, we launched an action research project in Yabu City, Hyogo Prefecture, to develop effective community-based strategies to prevent frailty in the elderly. We attempted to introduce community-based frailty prevention classes in every administrative district with the help of the senior workforce at Silver Human Resources Centers. This study aimed to evaluate the effectiveness and the applicability to different communities of this strategy, which will be called the "Yabu model."Methods　Using PAIREM (Plan, Adoption, Implementation, Reach, Effectiveness, Maintenance) framework, we evaluated the effectiveness and the applicability to different communities of the Yabu model. To evaluate its effectiveness, we conducted a baseline and follow-up survey of residents aged 65 years or older in 2012 (n=7,287, 90.7% response rate) and 2017 (n=8,157, 85.7%), using a mailed self-administered questionnaire.Results　(1) Plan: The idea was to establish a frailty prevention class (60 min/session, once a week) consisting of resistance exercises and nutritional or psychosocial programs (standard course, six months, 20 sessions/course; short course, one and a half months, 6 sessions/course; after the course, residents continued with the activities themselves). We planned to launch three classes in the first year (2014) and then to increase the number of classes by ten each year after the second year. (2) Adoption: Out of 154 administrative districts, 36 (23.4%) held frailty prevention classes between 2014 and 2017. (3) Implementation: The median attendance rate for the standard or short course (number of times each participant attended/number of frailty prevention class sessions held) was 75.0%. (4) Reach: A total of 719 older people participated in the standard or short course. The participation rate in the administrative districts, where each frailty prevention class was held, was 32.8%, while at the city level it was 8.1%. (5) Effectiveness: Propensity score matching after multiple imputations were performed. While the prevalence of frailty in non-participants increased by 13.7% in the five years from 2012 to 2017, it only increased by 6.8% in participants. Compared to non-participants, program participants had a significantly lower prevalence odds ratio of frailty at the time of the follow-up survey (OR=0.65, 95% confidence interval 0.46-0.93). (6) Maintenance: After the standard or short course, 25 out of 26 communities (96.2%) continued the frailty prevention activities once a week.Conclusion　The frailty prevention classes were adopted across many districts and lowered the participants' risk of frailty. Moreover, participants continued to engage in frailty prevention activities even after the course. These results indicate the Yabu model's effectiveness and its applicability for a different community.