Predictive Validity of Intrinsic Capacity Composite Scores for Risk of Frailty at 2 Years: A Comparison of 4 Scales

Objective: Intrinsic capacity (IC) and frailty are complementary constructs that encapsulate functional capacities of older adults. Although earlier studies suggest the utility of composite IC scores in predicting risk of frailty, key gaps remain with the lack of direct comparative studies between different IC scales and lack of a composite score based on the World Health Organization Integrated Care for Older People (ICOPE) tool. We aimed to compare different IC scales, including an ICOPE-based scale, in their predictive ability for risk of frailty at 2 years in healthy community-dwelling older adults.

Design: Cohort study.

Setting and participants: A total of 230 participants (age: 67.2 ± 7.4 years) from the GeriLABS-2 cohort study.

Methods: We derived composite scores by summing 4 IC domains (locomotion, cognition, vitality, and psychological). We compared composite scores of 4 scales: IC1-Chew 2021, range: 0-8; IC2-Liu 2021, range: 0-4; IC3-ICOPE, range: 0-4; IC4-modified ICOPE, range: 0-8. The primary outcome was risk of frailty using the modified Fried Frailty Phenotype. We performed logistic regression to examine the association of baseline composite IC with risk of frailty. We also examined the impact of individual domains and number of impaired domains on risk of frailty.

Results: Among 193 (83.9%) older adults who completed 2-year follow-up, 20 (10.4%) met criteria for risk of frailty. When adjusted for covariates, 2-point per domain scales (IC1/IC4) predicted increased risk of frailty (OR, 4.31; 95% CI, 1.55-11.96; OR, 5.00; 95% CI, 1.75-14.26). When further adjusted for baseline frailty, only IC4 remained significant (OR, 4.28; 95% CI, 1.45-12.60). Among the domains, impaired locomotion and vitality were associated with risk of frailty. Greater number of impaired domains predicted increased risk of frailty (IC1/IC2: β = 0.18-0.19, P < .05).

Conclusions and implications: Baseline composite IC score using 2-point per domain scales better predicted risk of frailty at 2 years, predicated on impaired locomotion/vitality and greater number of impaired domains. For early identification of healthy older adults at risk of frailty, an ICOPE-based scale should be considered, as it is effective and accessible.