Intrinsic capacity and multimorbidity predicting incident disability–Insights from the I-Lan Longitudinal Aging Study

Objectives This longitudinal cohort study aimed to examine the effect of intrinsic capacity (IC) and multimorbidity on the development of new disabilities. Methods The study utilized data from 1,009 participants without disabilities from the I-Lan Longitudinal Aging Study. Multivariable logistic regressions were employed to assess the predictive capability of IC (ranging from 0 to 100) and multimorbidity for incident disability over a 7-year follow-up period. Results Both low IC (OR 4.9, 95 % CI 2.1–11.1, p < 0.001) and multimorbidity (OR 4.5, 95 % CI 2.2–9.2, p < 0.001) significantly predicted incident disability over the 7-year period. A one-point increase in IC reduced the risk of incident disability by 10 % (OR 0.9, 95 % CI 0.8–0.9, p < 0.001). Among IC subdomains, both better locomotion (OR 0.96, 95 % CI 0.94–0.99, p = 0.014) and psychology (OR 0.97, 95 %CI 0.94–1.00, p = 0.049) significantly reduced the risk of incident disability. Rapid declines in IC significantly predicted incident disability (OR 4.1, 95 % CI 1.8–9.3, p = 0.001), whereas the onset of new multimorbidity or changes in the number of chronic conditions did not demonstrate a significant association with incident disability. The interaction terms between IC and multimorbidity, both categorically (low IC * multimorbidity, p = 0.959) and numerically (IC (per point) * multimorbidity, p = 0.660) were all statistically insignificant. Conclusions IC exhibited better predictive capacity for 7-year incident disability compared to multimorbidity, so health care services targeting older adults should adopt an integrated care approach that combines both function- and disease-centric strategies.