Effects of comorbid physical frailty and low muscle mass on incident disability in community-dwelling older adults: A 24-month follow-up longitudinal study

Abstract

ObjectivesLow muscle mass frequently precedes or coexists with physical frailty in late life. This study aimed to examine whether comorbid physical frailty and low muscle mass increase the risk of incident disability in community-dwelling older adults. Study designA prospective cohort study. MethodsParticipants were 9229 community-dwelling older Japanese adults (≥65 years). Longitudinal data on incident disability were collected for up to a maximum of 24 months from baseline. Physical frailty was defined as experiencing three or more of the following five symptoms: slowness, weakness, exhaustion, low activity, and weight loss. Low muscle mass was identified based on the AWGS definition (<7.0 kg/m2 for men and <5.7 kg/m2 for women). ResultsDuring the follow-up period, 460 (5.0%) individuals had incident disability. The prevalence rates of low muscle mass, physical frailty, and comorbid physical frailty and low muscle mass were 12.0% (n = 1104), 6.8 % (n = 624), and 1.8 % (n = 167), respectively. Compared with non-physical frailty/normal muscle mass, physical frailty (hazard ratio (HR) 2.50, 95% confidential interval (CI) 1.97−3.18) and comorbid physical frailty and low muscle mass (HR 4.03, 95% CI 2.85−5.70) were significantly associated with incident disability after adjusting for the covariates. ConclusionsAlthough low muscle mass alone may not be associated with an increased risk of incident disability in community-dwelling older adults, comorbid physical frailty and low muscle mass had a significant impact on disability. Low muscle mass was a risk factor for disability in older adults with physical frailty.