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.