Optimizing sarcopenia screening in type 2 diabetes mellitus: A ROC curve evaluation of the SARC-F and the SARC-CalF

Objectives: Sarcopenia is highly prevalent in older adults with type 2 diabetes mellitus (T2DM), significantly increasing fall and disability risks. While the Questionnaire composed of "Strength, Assistance in walking, Rising from a chair, Climbing stairs, and Falls" (SARC-F) is commonly used for sarcopenia screening, its diagnostic accuracy in T2DM patients remains unclear. SARC-CalF, an extended version incorporating calf circumference, may enhance screening effectiveness. This study aimed to evaluate the reliability, validity, and diagnostic accuracy of SARC-F and SARC-CalF in older T2DM adults. Methods: A cross-sectional study was conducted with 157 T2DM patients aged 60 years and above. Sarcopenia was assessed using both SARC-F and SARC-CalF, with the 2019 Asian Working Group for Sarcopenia criteria serving as the reference standard. Collected data included demographics, muscle mass (via bioelectrical impedance analysis), muscle strength (handgrip and five-time sit-to-stand tests), and physical performance (timed up-and-go test). Reliability, validity, and diagnostic accuracy were analyzed using validated statistical techniques. Results: SARC-F demonstrated good internal consistency (Cronbach's α = 0.80) and test-retest reliability (ICC = 0.89), moderate diagnostic accuracy (AUC = 0.65, 95% CI: 0.565-0.743) with an optimal cut-off score of 2.5 (sensitivity = 51.4%, specificity = 78.2%). SARC-CalF shows superior diagnostic performance (AUC = 0.98, 95% CI: 0.956-1.000 with higher sensitivity (92%) and specificity (94%). Conclusions: While the SARC-F is a reliable and valid screening tool for T2DM patients, its diagnostic accuracy is limited. SARC-CalF significantly improves screening performance and is preferable for chronic care monitoring.