Abstract / Summary
Background: Intrinsic capacity (IC), the composite of physical and mental capacities, underpins the WHO Integrated Care for Older People (ICOPE) program. IC may be measured as a brief screen, a comprehensive assessment, or a latent factor score; whether the simpler measures retain the prognostic information of the complex ones remains untested within a single population. Methods: In the nationwide Korean Frailty and Aging Cohort Study, 3011 community-dwelling adults aged 70–84 years (mean age, 76.0 [SD, 3.9] years; 52.5% women) were assessed for frailty and for activities of daily living (ADL) and instrumental ADL (IADL) disability and followed for mortality (median, 8.0 years). IC was measured by a Korean ICOPE screening score (K-ICOPE), a comprehensive clinical score (CIC), and a bifactor latent score (LIC); differences in discrimination were tested formally. Results: Discrimination for frailty rose with measurement intensity (area under the curve, 0.82, 0.86, 0.90; all pairwise P < .001) but not for ADL or IADL disability (all P ≥ .25). There were 500 deaths. Adjusted for sociodemographics and multimorbidity, each 1-SD higher IC was associated with lower mortality (hazard ratio 0.83 [95% CI, 0.75–0.91], 0.71 [0.64–0.78], 0.65 [0.58–0.73]), with closely similar discrimination (C statistic, 0.723, 0.731, 0.736; largest difference, 0.013 [0.005–0.021]). Discrimination from IC alone was lower and similar across measures (0.583, 0.604, 0.585). Conclusions: Measurement intensity improved the characterization of frailty but added little to the ranking of long-term mortality risk. Because K-ICOPE was aligned by construction to the latent structure, these findings support the potential feasibility of brief ICOPE-style screening rather than validating the WHO instrument.