How do we define and measure sarcopenia? A meta-analysis of observational studies

Abstract Objective this study aimed to investigate how sarcopenia has been defined and measured in the literature reporting its prevalence, and how different definitions and measurement tools can affect prevalence estimates. Design systematic review and meta-analysis. Setting and participants community-dwelling older people. Methods meta-analysis of data collected from observational studies. We performed an electronic search in five databases to identify studies reporting the prevalence of sarcopenia. We used descriptive statistics to present data pertaining sarcopenia definition and measurement tools, and the quality-effects model for meta-analysis of pooled prevalence. Results we found seven different operational definitions for sarcopenia and a variety of tools applied to assess the sarcopenic markers; muscle mass, muscle strength and physical performance. The prevalence of sarcopenia varied between the definitions with general estimates ranging from 5% based on the European Working Group on Sarcopenia in Older People (EWGSOP1) criterion to 17% with the International Working Group on Sarcopenia. According to the tool used to assess muscle mass, strength and physical performance, prevalence values also varied within definitions extending from 1 to 7%, 1 to 12% and 0 to 22%, respectively. Conclusion and implications the criteria used to define sarcopenia, as well as the measurement tools applied to assess sarcopenic markers have influence in the prevalence of sarcopenia. The establishment of a unique definition for sarcopenia, the use of methods that guarantee an accurate evaluation of muscle mass and the standardisation of measurement tools are necessary to allow a proper diagnosis and comparison of sarcopenia prevalence among populations.