Sarcopenia and Low Serum Albumin Level Synergistically Increase the Risk of Incident Disability in Older Adults

OBJECTIVES: This study aimed to investigate the additive effects of sarcopenia and low serum albumin level on the risk of incident disability in older adults. DESIGN: Prospective cohort study. SETTING: A Japanese community. PARTICIPANTS: Community-dwelling older adults aged ≥65 years, without disability at baseline (N = 4452). MEASURES: Sarcopenia was defined as the presence of both poor muscle function (low physical performance or muscle strength) and low muscle mass. Low serum albumin level was defined as ≤4.0 g/dL. Other potential confounding factors (demographics, medical history, depressive symptoms, and cognitive function) were also assessed. Incident disability was monitored based on Long-Term Care Insurance certification during follow-up. RESULTS: The median follow-up duration was 30 (interquartile range, 28-32) months. Participants were classified into mutually exclusive groups based on sarcopenia status and serum albumin levels: nonsarcopenia/normal serum albumin (n = 3719), low serum albumin alone (n = 552), sarcopenia alone (n = 132), and sarcopenia/low serum albumin (n = 49). A Cox hazards regression showed that the low serum albumin alone [hazard ratios (HR) = 1.71, 95% confidence interval (CI) = 1.26-2.33], sarcopenia alone (HR = 2.74, 95% CI = 1.58-4.77), and sarcopenia/low serum albumin groups (HR = 3.73, 95% CI = 1.87-7.44) had higher risk of disability than the nonsarcopenia/normal serum albumin group after adjusting for the covariates. CONCLUSIONS/IMPLICATIONS: Sarcopenia and low serum albumin level synergistically increase the risk of incident disability in older adults. Sarcopenia in older adults at risk of malnutrition should be detected early, and appropriate interventions should be implemented.