Effects of intrinsic capacity on health-related outcomes are moderated by frailty status among community-dwelling older adults.

OBJECTIVES: To examine whether frailty moderates associations between intrinsic capacity (IC) losses and health-related outcomes among community-dwelling older adults. DESIGN: Secondary analysis of a longitudinal cohort study. SETTING: Community in Singapore. PARTICIPANTS: Adults aged ≥55 years from the Individual Physical Proficiency Test for Seniors cohort. MEASUREMENTS: IC was assessed using the Integrated Care for Older People Step One questions, and frailty using Clinical Frailty Scale (CFS). Outcomes included ADL and iADL, Life Space Assessment, self-rated health (SRH), EQ-5D-5L, hospitalizations, A&E visits, and falls. Linear mixed and Cox proportional hazard models were used, with multiple imputation and sensitivity analyses for missing data. RESULTS: Among 1109 participants (mean age 67.7(SD 6.8) years; 73% female; 86% Chinese), 308(28%) were frail (CFS > 3). Higher cumulative IC losses were associated with iADL decline over time (IC losses × Year2 β = -0.305; 95%CI -0.50 to -0.11; p < 0.01), poorer SRH (β = -1.624; 95%CI -2.593 to -0.654; p = 0.001), lower EQ-5D-5L scores (β = -0.00689; 95%CI -0.012 to -0.001; p < 0.05), and higher hospitalization risk (HR = 1.47; 95%CI 1.08-2.01; p < 0.05). Significant IC losses × frailty interactions were observed for iADL and EQ-5D-5 L, which remained significant in imputation and sensitivity analyses. In subgroup analyses, IC losses remained associated with poorer quality-of-life measures and iADL decline among both non-frail and frail participants. CONCLUSION: The effect of IC on health-related outcomes is influenced by frailty status. The sub-group analysis supported the detrimental effect of IC loss even among non-frail older adults. These findings support IC assessment alongside frailty evaluation.