Abstract
BACKGROUND: Frailty and multimorbidity are independent prognostic factors for mortality, but their interaction has not been fully explored. We investigated the importance of multimorbidity patterns in older adults with the same level of frailty phenotype. METHODS: In a cohort of 7,197 community-dwelling adults aged 65 years and older, physical frailty status (robust, pre-frail, frail) was defined using shrinking, exhaustion, inactivity, slowness, and weakness. Latent class analysis was used to identify individuals with multimorbidity patterns based on 10 self-reported chronic conditions. We estimated hazard ratios (HR) and incidence rate differences (IRDs) for mortality comparing multimorbidity patterns within each frailty state. RESULTS: Five multimorbidity classes were identified: minimal disease (24.7%), cardiovascular disease (29.0%), osteoarticular disease (27.3%), neuropsychiatric disease (8.9%), and high multisystem morbidity (10.0%). Within each frailty state, the mortality rate per 1,000 person-years over 4 years was greatest in the neuropsychiatric class and lowest in the minimal disease class: robust (56.3 vs 15.7; HR, 2.11 [95% CI: 1.05, 4.21]; IRD, 24.1 [95% CI: -11.2, 59.3]), pre-frail (85.3 vs 40.4; HR, 1.74 [95% CI: 1.28, 2.37]; IRD, 27.1 [95% CI: 7.6, 46.7]), and frail (218.1 vs 96.4; HR, 2.05 [95% CI: 1.36, 3.10]; IRD, 108.4 [95% CI: 65.0, 151.9]). Although HRs did not vary widely by frailty, the excess number of deaths, as reflected by IRDs, increased with greater frailty level. CONCLUSIONS: Considering both multimorbidity patterns and frailty is important for identifying older adults at greater risk of mortality. Of the five patterns identified, the neuropsychiatric class was associated with lower survival across all frailty levels.