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Background Decreased skeletal muscle mass and low physical performance are independently associated with increased mortality in elderly individuals. However, little is known about the effects of skeletal muscle mass combined with physical performance on the prediction of mortality risk among community-dwelling older adults. This study aimed to determine the combined effects of skeletal muscle mass and physical performance on total mortality. Methods A community-based prospective cohort study was conducted among 641 participants aged 65 and older in 2009. The height-adjusted skeletal muscle index (hSMI) and the weight-adjusted SMI (wSMI) were determined by dual-energy X-ray absorptiometry examination. Physical performance tests measured at baseline included gait speed (GS), timed up-and-go (TUG) test, timed chair stand (TCS), weight-adjusted leg press (WaLP), and handgrip strength (HS). Cox proportional hazards regression models were applied to determine the adjusted hazard ratios (HRs) of mortality with 95% confidence intervals (95% CIs) for baseline skeletal muscle mass, physical performance, and traditional risk factors. Results During the follow-up of 12 years, 198 (30.89%) participants died. Low hSMI, low GS, high TUG, high TCS, low WaLP, and low HS were associated with high risks of mortality after the adjustment for confounders. The results of receiver operating characteristic (ROC) curve analyses revealed the values of ROC for models with additional consideration for TUG or all indicators significantly improved the discriminatory ability of mortality compared with the model with traditional factors (all P Conclusion The hSMI and physical performance are significantly associated with increased risks of all-cause mortality. The combined use of hSMI and physical performance can provide improved risk stratification, which may be appropriately used as a screening tool targeting high-risk elders for the effective prevention of sarcopenia-related mortality.

Background Multiple chronic conditions and low skeletal muscle mass are common features of aging that are detrimental to physical performance. This study evaluates the simultaneous impact of these conditions on physical performance in older adults. Methods Five studies from 2003 to 2012 were pooled to include 2,398 adults aged ≥65 years with diagnosed chronic diseases measured by self-administered questionnaire. Low muscle mass was defined as an appendicular skeletal muscle mass index less than that of the sex-specific lowest quintile in the population of older adults. Poor physical performances were defined as the lowest quintile of grip strength and gait speed in the population of older adults and the slowest sex-specific 20% of Timed Up and Go (TUG) test at each study site. Chi-squared and logistic regression tests were applied for data analysis. Results Mean age of the study participants, of whom approximately 50% were men, was 74.3 years. Slow gait speed was nearly three times more likely to occur in the presence of low muscle mass coupled with chronic disease than in the absence of both factors after adjustment for study site, age, sex, education, marital status, body mass index, tobacco and alcohol use, and comorbidities. The independent effect of low muscle mass was generally stronger than that of each disease. Participants with more than two chronic diseases and low muscle mass were significantly more likely to perform poorly than those with no risk factors (odds ratio [OR] = 2.51 in patients with low grip strength, OR = 3.89 in patients with low gait speed, and OR = 3.67 in patients with poor TUG test scores, all P