Validation of the German version of the SarQoL® questionnaire in sarcopenic and probable sarcopenic patients.

Background: The German version of the SarQoL^®, a sarcopenia-specific quality of life (QoL) questionnaire, has not been validated hindering its widespread use. This study aimed to evaluate the psychometric properties of the German SarQoL^®. Methods: Via a cross-sectional study participants were recruited in two geriatric outpatient facilities and one acute geriatric ward in Munich (Germany). Sarcopenia and probable sarcopenia were diagnosed with the European Working Group on Sarcopenia in Older People (EWGSOP2) algorithm. From 185 participants (age 79.8 ± 6.1), 77 had probable sarcopenia, and 51 had sarcopenia. Participants completed the SarQoL^® and the European Quality-of-Life 5-Dimension (EQ-5D) questionnaires. The validation included examination of the discriminative power, construct validity, internal consistency, test-retest reliability, and floor/ceiling effects. Results: Lower SarQoL^®scores for sarcopenic (p = 0.002) and probable sarcopenic subjects (p < 0.001) compared to controls indicated good discriminative power. Consistent construct validity was found for sarcopenic subjects: moderate to high correlations with domains capturing similar constructs of the EQ-5D: 'Activities of daily living' (r = -0.58, p < 0.001), 'Mobility' (r = -0.72, p < 0.001) and low correlations with domains related to different constructs like 'Pain' (r = -0.32, p < 0.022). Similar correlations were found for probable sarcopenic subjects. The Cronbach's alpha was 0.8. Test-retest reliability was excellent (intraclass coefficient correlation of = 0.96; 95% CI = 0.91–0.99), and no floor/ceiling effects were observed. Conclusion: QoL was similarly reduced in both patient cohorts compared to controls. The German SarQoL^® is a valid and reliable instrument for measuring QoL in patients > 65 years of age with sarcopenia and probable sarcopenia and can now be used in epidemiological studies and clinical trials in a German-speaking population. Trial registration: German Clinical Trials Register (DRKS)-ID: DRKS00020504 (March 12th, 2021). [ABSTRACT FROM AUTHOR]