Intrinsic capacity and recent falls in adults 80 years and older living in the community: results from the ilSIRENTE Study

Background: Falls in older adults significantly impact overall health and healthcare costs. Intrinsic capacity (IC) reflects functional reserve and is an indicator of healthy aging. Aims: To explore the association between IC and recent falls (≤ 90 days) in community-dwelling octogenarians from the Aging and Longevity in the Sirente geographic area (IlSIRENTE) study. Methods: The Minimum Data Set for Home Care (MDS-HC) and supplementary questionnaires and tests were used to assess the five IC domains: locomotion, cognition, vitality, psychology, and sensory. Scores in each domain were rescaled using the percent of maximum possible score method and averaged to obtain an overall IC score (range 0-100). Results: The study included 319 participants (mean age 85.5 ± 4.8 years, 67.1% women). Mean IC score was 80.5 ± 14.2. The optimal IC score cut-off for predicting the two-year risk of incident loss of at least one activity of daily living (ADL) was determined and validated in a subset of 240 individuals without ADL disability at baseline (mean age 84.7 ± 4.4 years, 67.1% women). Participants were then stratified into low (< 77.6) and high (≥ 77.6) IC categories. Those with high IC (63.9%) were younger, more often males, and had lower prevalence of recent falls, disability, multimorbidity, and polypharmacy. Logistic regression models including IC as a continuous variable revealed a significant association between higher IC and lower odds of falls. This association was significant in the unadjusted (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94-0.98, p < 0.001), age- and sex-adjusted (OR 0.96, 95% CI 0.94-0.98, p < 0.001), and fully adjusted models (OR 0.96, 95% CI 0.93-0.99, p = 0.003). When considering IC as a categorical variable, unadjusted logistic regression showed a strong association between high IC and lower odds of falls (OR 0.31, 95% CI 0.16-0.60, p < 0.001). This association remained significant in both the age- and sex-adjusted (OR 0.30, 95% CI 0.15-0.59, p < 0.001) and fully adjusted models (OR 0.33, 95% CI 0.16-0.82, p = 0.007). The locomotion domain was independently associated with falls in the unadjusted (OR 0.98, 95% CI 0.97-0.99, p < 0.001), age- and sex-adjusted (OR 0.97, 95% CI 0.96-0.99, p < 0.001), and fully adjusted model (OR 0.98, 95% CI 0.96-0.99, p < 0.001). Discussion: This is the first study using an MDS-HC-derived instrument to assess IC. Individuals with higher IC were less likely to report recent falls, with locomotion being an independently associated domain. Conclusions: Lower IC is linked to increased odds of falls. Interventions to maintain and improve IC, especially the locomotion domain, may reduce fall risk in community-dwelling octogenarians.