Validity of Total Kihon Checklist Score for Predicting the Incidence of 3-Year Dependency and Mortality in a Community-Dwelling Older Population

Objectives: To validate the ability of the total Kihon checklist (t-KCL) score to predict the incidence of dependency or death within 3 years in a community-dwelling older population.

Design: Population-based longitudinal observational study.

Setting: Town of Higashi-ura, Japan.

Participants: A total of 5542 independent seniors who were residents in the town of Higashi-ura.

Measurements: The KCL questionnaire was sent to independent older residents. Based on our previous report, those with a t-KCL score of 0-3 were classified as robust, 4-7 as pre-frail, and 8 + as frail. The incidence of dependency or death was observed over 3 years. Dependency was defined as a new certification for long-term care insurance (LTCI) service need. Information regarding LTCI certification or death was obtained from the municipal government.

Results: Of 8091 independent older adults, 5542 seniors completed the KCL questionnaire. Based on the t-KCL score, they were classified into 3 groups: 2962 (53.4%) as robust, 1625 (29.3%) as pre-frail, and 955 (17.2%) as frail. Over the 3 years, 510 seniors (9.2%) had new LTCI certifications and 170 (3.1%) died. Cox regression analysis adjusted for age and sex showed that the classification of frailty status by t-KCL score was significantly associated with the incidence of dependency both in the pre-frail and the frail [hazard ratios (HRs): 2.027 and 4.768; 95% confidence intervals (CIs): 1.575-2.608 and 3.733-6.089, respectively]. On the other hand, the ability to predict death was significant, but only in the frail group (HR: 2.830; 95% CI: 1.952-4.104).

Conclusion: The classification of frailty status by t-KCL score could be a significant tool to predict the incidences of dependency and mortality in older adults.