SARC‐F and modified versions using arm and calf circumference: Diagnostic performance for sarcopenia screening and the impact of obesity

Abstract

AimSARC‐F is limited by low sensitivity for sarcopenia identification. As surrogates of muscle mass, mid‐arm circumference (MAC) and/or calf circumference have been proposed as additions to SARC‐F to enhance sarcopenia identification. The aim of this study was to evaluate the diagnostic performance of SARC‐F, SARC‐CalF, SARC‐F + MAC, and SARC‐CalF + MAC in sarcopenia detection, and to assess the impact of obesity on their diagnostic performance.MethodsWe studied 230 healthy non‐frail community‐dwelling older adults age >50 years. We performed receiver operating characteristic curve analysis for SARC‐F, SARC‐CalF, SARC‐F + MAC and SARC‐CalF + MAC against sarcopenia diagnosed by the Asian Working Group for Sarcopenia (AWGS) 2019 as the reference standard. Obesity was defined by high waist circumference (men ≥90 cm, women ≥80 cm). We performed subgroup analysis to compare between obese and non‐obese groups.ResultsThe prevalence of sarcopenia was 27.0% by AWGS 2019. SARC‐CalF + MAC had the best diagnostic performance (area under the curve [AUC] 0.74, 95% confidence interval [CI] 0.67–0.81; sensitivity 66.1%; specificity 69.1%), followed by SARC‐CalF (AUC 0.70, 95% CI 0.62–0.78; sensitivity 21.0%; specificity 95.8%). SARC‐F (AUC 0.57, 95% CI 0.49–0.66; sensitivity 0%; specificity 100%) performed significantly worsethan its modified versions (P < 0.05). There was higher accuracy of sarcopenia identification in obese compared with non‐obese groups for SARC‐F + MAC (AUC 0.75, 95% CI 0.65–0.85 vs. 0.58, 95% CI 0.46–0.70) and SARC‐CalF + MAC (AUC 0.75, 95% CI 0.66–0.85 vs. 0.70, 95% CI 0.59–0.81).ConclusionsThe addition of arm circumference to SARC‐CalF confers better diagnostic accuracy for sarcopenia identification, especially in the obese group. Thus, MAC may complement SARC‐CalF for community screening of sarcopenia amongst healthy community‐dwelling older adults by increasing sensitivity for the detection of sarcopenic obesity. Geriatr Gerontol Int 2023; ••: ••–••.