Prevalence of sarcopenia under different diagnostic criteria and the changes in muscle mass, muscle strength, and physical function with age in Chinese old adults

Background At present, there are several diagnostic criteria of sarcopenia were used in China, and the diagnostic criteria were not unified. This study aims to investigate the consistency between the latest sarcopenia diagnostic criteria Asian Working Group for Sarcopenia(AWGS 2019) and other common diagnostic criteria. The changes of muscle mass, muscle strength and physical function with age and their effects on the diagnosis of sarcopenia were also analyzed. Methods A total of 1009 men aged >= 60 years were enrolled from multiple communities. Skeletal muscle mass index, grip strength and 6 m gait speed were measured. The consistency of AWGS 2019 with other diagnostic criteria was analyzed and the trends of these three indicators were observed. The differences of muscle mass, muscle strength and function among different diagnostic criteria and age groups were evaluated. In addition, the change trends of these three indicators with age were observed. Results According to AWGS 2019 diagnostic criteria, the incidence of sarcopenia in male aged 60-69 years, 70-79 years and over 80 years was 1.5%, 9.6% and 33.1%, respectively. AWGS 2019 was highly consistent with other diagnostic criteria (Kappa = 0.66-0.80, P < 0.01), except the Foundation for the National Institutes of Health(FNIH) (Kappa = 0.32, P < 0.01). When AWGSA2019 diagnostic criteria are applied, the prevalence of decreased muscle strength (39.1%) and physical function (46.4%) was significantly higher than that of low muscle mass (35.9%) in the men over 80 years old. Muscle strength (P < 0.01) and function (P < 0.01) decreased at the same rate with age, both of which were more significant than muscle mass (P < 0.01). Conclusion AWGS 2019 was highly consistent with other criteria. Maintaining muscle mass should be the focus of attention before age 80, while improving muscle strength and function should be focused after age 80 to prevent disability.