Comparing two common frailty measures in the resident assessment instrument in home care (RAI-HC): a cross-sectional cohort study in Alberta

Background Many older adults living with frailty rely on publicly funded home care services; however, the health profile of home care clients in Alberta is not well characterized, particularly regarding how different frailty measures embedded within the Resident Assessment Instrument in Home Care (RAI-HC) classify frailty. We aimed to compare the Changes in Health, End-stage disease and Signs Scale (CHESS) and the 72-item Frailty Index (Full FI) in this study. Methods A cross-sectional study was conducted using Alberta population-based administrative data linked to RAI-HC assessments for long-stay home care clients aged 65–104 years ( N = 19,916) between 2015 and 2016. Various health and functional characteristics were summarized across robust, pre-frail, and frail groups as defined by CHESS and Full FI. Group differences were examined using chi-square tests, and agreement between measures was assessed using a weighted kappa statistic. Results Frailty prevalence differed markedly by measure: 27% were classified as frail using CHESS compared with 11% using the Full FI. Agreement between measures was fair ( k = 0.31), reflecting their measurement of different constructs; acute health instability (CHESS) versus multidimensional deficit accumulation (Full FI). Conclusions Differences in frailty classification underscore the conceptual distinctions between CHESS and the Full FI. The Full FI is feasible to derive from RAI-HC data and may better identify modifiable deficits relevant to care planning, while CHESS is more sensitive to acute deterioration. Using both measures together may enhance frailty identification, support tailored home care interventions, and improve resource allocation for older adults aging in place.