Prevalence and Risk Factors Governing the Loss of Muscle Function in Elderly Sarcopenia Patients: A Longitudinal Study in China with 4 Years of Follow-Up

Objectives Data regarding the occurrence of risk factors that promote the loss of muscle mass, strength and function in sarcopenia patients in elderly Chinese patients are sparse. Here, we investigated the alterations in muscle mass, function and strength in those with sarcopenia over a 4-year period. We further evaluated the risk factors leading to a loss of grip strength, gait speed and skeletal muscle mass index in sarcopenia patients. Design A face-to-face cross-sectional survey. Setting and Participants The study population consisted of 560 Chinese aged over 59 years. Measurements Study recordings took places over a four-year period from 2014. Muscle mass was assessed through bioelectrical impedance analysis (BIA) performed on an Inbody720, Biospace. Hand-grip strength and 6 m walking speed were used as measurements of muscle strength and function. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria (AWGS). Results In total, 474 of the elderly residents completed the follow-up. The rates of decreased ASMI, grip strength, and gait speed in the sarcopenia patients increased over the 4-year period. Following multivariate analysis, age was identified as the main risk factor for all the observed decrease, gender was specifically related to the loss of ASMI, stroke was a risk factor for gait speed and sarcopenia. A high BMI was a risk factor for a low gait speed but was protective for a loss of skeletal muscle mass and sarcopenia. Conclusions Age leads to a decline in muscle strength and function. In elderly Chinese patients with sarcopenia, the rates of reduced grip strength, gait-speed and sarcopenia increased. A high BMI was protective against the decline in muscle mass and sarcopenia, but represented a risk factor for low gait speed. Stoke was identified to cause a loss of gait speed in sarcopenia patients.