Association of Intrinsic Capacity with Frailty, Physical Fitness and Adverse Health Outcomes in Community-Dwelling Older Adults

BACKGROUND: Intrinsic capacity (IC) and frailty are complementary in advancing disability prevention through maintaining functionality. OBJECTIVES: We examined the relationship between IC and frailty status at baseline and 1-year, and evaluated if IC decline predicts frailty onset among robust older adults. The secondary objectives investigated associations between IC, physical fitness and health-related outcomes. DESIGN: Prospective cohort study. SETTING: Community-based assessments. PARTICIPANTS: Older adults aged>55 years, who were independent in ambulation (walking aids permitted). MEASUREMENTS: 5 domains of IC were assessed at baseline: locomotion (Short Physical Performance Battery, 6-minute walk test), vitality (nutritional status, muscle mass), sensory (self-reported hearing and vision), cognition (self-reported memory, age- and education adjusted cognitive performance), psychological (Geriatric Depression Scale-15, self-reported anxiety/ depression). Composite IC (0-10) was calculated, with higher scores representing greater IC. Frailty status was based on modified Fried criteria, with frailty progression defined as incremental Fried score at 1-year. RESULTS: 809 participants (67.6+6.8 years) had complete data for all 5 IC domains. 489 (60.4%) participants were robust but only 213 (26.3%) had no decline in any IC domain. Pre-frail and frail participants were more likely to exhibit decline in all 5 IC domains (p<0.05), with decremental composite IC [9 (8-9), 8 (6-9), 5.5 (4-7.5), p<0.001] across robust, prefrail and frail. IC was significantly associated with fitness performance, independent of age and gender. Higher composite IC reduced risk for frailty progression (OR=0.62, 95% CI 0.48-0.80), and reduced frailty onset among robust older adults (OR=0.53, 95% CI 0.37-0.77), independent of age, comorbidities and social vulnerability. Participants with higher IC were less likely to experience health deterioration (OR=0.70, 95% CI 0.58-0.83), falls (OR=0.76, 95% CI 0.65-0.90) and functional decline (OR=0.64, 95% CI 0.50-0.83) at 1-year. CONCLUSION: Declining IC may present before frailty becomes clinically manifest, increasing risk for poor outcomes. Monitoring of IC domains potentially facilitates personalized interventions to avoid progressive frailty.