New versus old guidelines for sarcopenia classification: What is the impact on prevalence and health outcomes?

Introduction: recently, the European Working Group on Sarcopenia in Older People (EWGSOP) established a new operational definition and cut-off points for sarcopenia. The aim of this study was, therefore, to compare the prevalence of sarcopenia and its associations with different health outcomes using the old (EWGSOP1) and new (EWGSOP2) definitions of sarcopenia in the UK Biobank cohort. Methods: sarcopenia was defined as low grip strength plus low muscle mass. Using both EWGSOP cut-off points, we created specific sarcopenia variables. Prevalence of sarcopenia derived using both EWGSOP definitions was calculated and compared as well as prospective health outcomes including all-cause mortality as well as incidence and mortality from cardiovascular disease (CVD), respiratory disease and chronic obstructive pulmonary disease (COPD). Results: the prevalence of sarcopenia based on the EWGSOP1 and EWGSOP2 classifications were 8.14 and 0.36%, respectively. Sarcopenia defined by EWGSOP1 was associated with a higher risk of respiratory disease and COPD as well as mortality from all-cause, CVD and respiratory diseases. However, only respiratory incidence remained associated with sarcopenia when EWGSOP2 was used (HR: 1.32 [95% CI: 1.05-1.66]). Moreover, although individuals classified as sarcopenic using both classifications had the highest risk of all-cause mortality and respiratory disease, those with sarcopenia based on EWGSOP1 only experienced a more extensive range of poorer health outcomes. Conclusion: in comparison with EWGSOP1, the new classification (EWGSOP2) produced a lower estimate of sarcopenia prevalence and fewer associations with adverse health outcomes. Although these associations were higher, many become non-significant.