Translation and psychometric performance of the Serbian version of the sarcopenia quality of life (SarQoL®) questionnaire

Abstract

Introduction/Objective The Sarcopenia Quality of Life (SarQoL®) questionnaire is a patient-reported outcome measure specific to sarcopenia. The objective was to translate the SarQoL® questionnaire from English into Serbian and to investigate its psychometric performance. Methods A five-stage forward-backward methodology with pre-test was used to translate the question-naire. The validation sample in this study consisted of elderly, community-dwelling volunteers of both sexes. Three methods were used to screen for and diagnose sarcopenia: the SARC-F questionnaire (high/ low risk), low handgrip strength [probable sarcopenia in the European Working Group on Sarcopenia in Older People (EWGSOP2) algorithm], and the complete EWGSOP2 criteria. We investigated the ques-tionnaire’s discriminative power, internal consistency, construct validity, and floor and ceiling effects. Results The SarQoL® questionnaire was translated into Serbian. The validation study included 699 par-ticipants. In total, 200 participants were considered to be at high risk of sarcopenia by the SARC-F, 84 were diagnosed with low handgrip strength and 12 were confirmed to be sarcopenic. We did not find significantly lower overall QoL scores using the EWGSOP2 criteria (60.31 vs. 64.60; p = 0.155). We did find lower scores for the probably sarcopenic group (52.80 vs. 65.50; p < 0.001) and the high-risk group (50.91 vs. 69.02; p < 0.001). The Cronbach’s α coefficient was 0.87, indicating a high internal consistency. Construct validity was adequate, with 75% of hypotheses on expected correlations with the SF-36 and EQ-5D questionnaires confirmed. No floor or ceiling effects were observed. Conclusion We successfully translated the SarQoL® into Serbian, and showed that it is a valid tool for measuring QoL in the community-dwelling elderly.