Performance of the SARC-F, SARC-CalF, and calf circumference for sarcopenia case finding in community-dwelling older adults

Purpose: We compared the performance of SARC-F, SARC-CalF, calf circumference (CC), and body mass index (BMI)-adjusted CC for sarcopenia case-finding in community-dwelling older adults. Methods: Data of Finnish participants (women/men n = 192/36, mean age (SD) of 76.9 (4.8) years) recruited in the SPRINTT trial (NCT02582138) were used. Sarcopenia was determined as a combination of low muscle function (chair-stand-test) and low appendicular lean mass (ALM) detected by whole-body dual-energy X-ray absorptiometry. Associations of case-finding tools with sarcopenia were analysed using ROC curves and logistic regression. Results: The rates of probable and confirmed sarcopenia were 95% and 18% in women and 94% and 36% in men, respectively. Performance of CC for sarcopenia (women AUC 0.85 [95% CI 0.78-0.92]/ men 0.85 [95% CI 0.71-1.0]) was superior to that of other tools; (AUC in women/men for SARC-F was 0.57/0.50, for SARC-CalF 0.76/0.79, and for BMI-adjusted CC 0.68/0.66). The best performance was found for a CC cut-off point of ≤ 34 cm in women with sensitivity/specificity 82.4/75.3% and ≤ 36 cm in men with sensitivity/specificity 76.9/87.0%. For each cm decrease in CC, adjusted for age and BMI, there was a 30% increase in the odds of sarcopenia in women (OR 1.30, 95% CI 1.09─1.56). Although there was a similar pattern in men, the results did not reach statistical significance (OR 1.34, 95% CI 0.84- 2.14). Conclusions: CC was superior to other tools for sarcopenia case-finding. The best performance was found for a CC cut-off point of ≤ 34 cm in women and ≤ 36 cm in men.