Clinical sarcopenia identification: Justification for increased sensitivity in SARC-F scores for probable sarcopenia

Background The European Working Group on Sarcopenia in Older People (EWGSOP2) recommends the use of the 5-item SARC-F questionnaire by clinicians to screen for probable sarcopenia. The recommended threshold of ≥4 has low sensitivity and high specificity in identifying probable sarcopenia. While this high threshold is capable of excluding clients without probable sarcopenia, difficulty lies in using this screening tool to identify clients with low muscle strength. Methods 204 community-dwelling older adults (117 male, 87 female) above the age of 65 were screened at their physician visits using the SARC-F. Probable sarcopenia was diagnosed using gender-specific grip strength criteria defined by the EWGSOP2 (≤ 27 kg for men, ≤ 16 kg for women). A receiver operating characteristic (ROC) curve was used to determine a SARC-F threshold that optimized the tradeoff between sensitivity and specificity for diagnosis of probable sarcopenia. Results Probable sarcopenia was present in 11.8% of participants. There were no differences in age (73.9 ± 6.2 years) or BMI (29.5 ± 5.8 kg/m2) between genders. Males had greater grip strength (36.3 ± 8.1; 22.4 ± 5.5 kg) and lower SARC-F scores (0.92 ± 1.65, 1.88 ± 2.31) than females. The ROC curve identified a SARC-F score of ≥2 as an optimal cutoff between sensitivity and specificity (AUC = 0.77, 95% CI: 0.67 – 0.88, p < .05). Accuracy (0.77), false positive rate (0.22), positive predictive value (0.31), and negative predictive value (0.96) were also calculated. Conclusions A SARC-F threshold of ≥2 is recommended as an optimal tradeoff between sensitivity and specificity when identifying community-dwelling older adults with probable sarcopenia. This is lower than the currently accepted recommendation of ≥4. Our findings promote the recommended early detection and treatment by medical professionals by the EWGSOP2 by improving the ability to identify individuals with low muscle strength with this screening procedure.