Associations Between Apathy and Comprehensive Frailty As Assessed by the Kihon Checklist among Community-Dwelling Japanese Older Adults.

Background Frailty is a multidimensional condition characterised by reduced physical and psychological resilience. Older adults also frequently demonstrate apathy, suggesting that it shares similar neuro-physiological pathways with frailty. This cross-sectional study aimed to investigate the association between apathy and frailty as defined by a comprehensive assessment. Methods We analyzed 882 older adults (mean age: 74.4 +/- 6.4 years; 62.1% female) who participated in a community-based health check survey (Tarumizu Study). Apathy was measured by the Geriatric Depression Scale-3A, a three-item subset of the Geriatric Depression Scale-15, and frailty by the Kihon Checklist of physical, psychological, functional, and social status. Associations were examined by multinomial logistic regression with frailty status (robust, pre-frailty, frailty) as the dependent variable, apathy as the independent variable, and sociodemographic factors, medications, cognitive function, functional capacity, and mood symptoms as potential confounders. Results Apathy was observed in 23.7% of individuals, and logistic regression revealed significant associations with both pre-frailty and frailty after confounder adjustment (pre-frailty: odds ratio (OR) 1.80, 95% CI 1.22-2.64; frailty: OR 3.24, 95% CI 1.63-6.42). Participants with apathy also exhibited greater deficits in the Kihon Checklist subdomains instrumental activities of daily living (P = 0.022), physical function (P < 0.001), oral function (P < 0.001), and cognitive function (P = 0.001). Conclusions Our findings underscore the importance of comprehensive frailty assessment and demonstrate that apathy can have pervasive deleterious effects on geriatric health.