Accuracy of SARC-F test for screening of sarcopenia in adult dialysis patients

BACKGROUND: Sarcopenia is an important risk factor for increased morbidity and mortality in the dialysis population, but it is neither frequently diagnosed nor treated in the clinical practice. The aim of the study was to compare the prevalence of sarcopenia as assessed by the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria or by the Strength, walking Assistance, Rise up from a Chair, and Falls (SARC-F) questionnaire, and to evaluate the diagnostic accuracy of SARC-F as a screening tool for the risk of sarcopenia in an Italian cohort of patients on dialysis. METHODS: One hundred and four outpatients, 67 males and 37 females, aged more than 40 years, with kidney failure (KF) on chronic dialysis treatment were recruited in two Italian centers. Sarcopenia was diagnosed using EWGSOP2 criteria, namely low muscle strength, low muscle mass, poor physical performance; and using the SARC-F score, based on a short 5-item questionnaire that examines muscle strength, capacity of walking and of rising from a chair, and occurrence of falls. RESULTS: Sarcopenia was diagnosed in 46 cases using EWGSOP2 criteria and in 31 cases using the SARC-F score, thus the prevalence of sarcopenia was greater using the former criteria than when using the latter questionnaire (44.2% vs 29.8%, P <.05). The SARC-F score had high specificity (93.6%) and a high positive predictive value (87%) but moderate sensitivity (60%) when compared with EWGSOP2 criteria. CONCLUSION: SARC-F shows high specificity but moderate sensitivity in a cohort of Italian patients on chronic dialysis. Because of the high false negative rate, SARC-F should not replace, but may complement objective diagnostic measures in this high-risk population.