Predictive validity of a 10-item frailty index based on a comprehensive geriatric assessment (FI-CGA-10) in older Japanese adults with cancer.

BACKGROUND: The 10-Item Frailty Index Based on a Comprehensive Geriatric Assessment (FI-CGA-10) is a content- and construct-validated measure for quantifying frailty from a CGA. For criterion validation, we assessed its predictive validity for overall survival (OS) in older adults with cancer. METHODS: This prospective cohort study included 1,630 patients with cancer who underwent CGA at a geriatric oncology service (median age 80 years). The FI-CGA-10 comprises ten CGA domains; deficits in each domain were scored 0 (no problem), 0.5 (minor problem), or 1.0 (major problem). Domain scores were summed, divided by 10 (range 0-1), and categorized as fit (<0.20), pre-frail (0.20-0.35), or frail (>0.35). Two Cox proportional hazards models estimated hazard ratios (HRs) for OS: a base model (age, sex, cancer type, and stage) and the base model plus FI-CGA-10 as a categorical variable. Model performance was compared using the likelihood-ratio (LR) test and Harrell's c-index. RESULTS: Overall, 22% were fit, 38% pre-frail, and 40% frail; 28% died within one year. Adding FI-CGA-10 to the base model improved prediction (LR χ² = 140.7; P < .001) and increased the c-index from 0.70 to 0.76 (P < .001). Adjusted HRs for pre-frail and frail (vs. fit) were 2.26 (95% CI, 1.61-3.19) and 5.06 (95% CI, 3.64-7.04), respectively. 1-year OS was 87% (fit), 74% (pre-frail), and 55% (frail). Major problems across all ten domains and minor problems in six domains were associated with worse OS in adjusted models. CONCLUSION: This study provides evidence supporting the predictive validity of the FI-CGA-10 for OS.