Evaluation of the responsiveness of the SarQoL® questionnaire, a patient-reported outcome measure specific to sarcopenia.

INTRODUCTION: The Sarcopenia Quality of Life (SarQoL®) questionnaire was developed to provide a patient-reported outcome measure specific to sarcopenia. Its psychometric properties indicate that it is a valid and reliable instrument. However, until now, its ability to detect change over time has not been examined. Therefore, the objective of this study is to evaluate the responsiveness (also known as sensitivity to change) of the SarQoL® questionnaire in a prospective, longitudinal cohort of community-dwelling, older, sarcopenic subjects.
METHODS: Sarcopenic subjects from the SarcoPhAge (Sarcopenia and Physical impairment with advancing Age) study were included. Responsiveness was evaluated with nine pre-specified hypotheses on the correlation between the evolution of the SarQoL® scores after a 2-year interval and the evolution of the scores on the Short Form-36 (SF-36) and the Euroqol 5-dimension (EQ-5D) questionnaires. This technique considers responsiveness to be a form of longitudinal validity. Additionally, standardized response means were also calculated to compare the quantity of change measured by the different questionnaires.
RESULTS: A total of 42 sarcopenic subjects were included. The median age of the sample was 72.9 (68.9-78.8) years, 59.5% were female, and the mean body mass index was 23.3 (20.4-25.7) kg/m2. A good responsiveness was observed, as evidenced by the confirmation of eight out of nine hypotheses, well above the 75% confirmation threshold. The standardized response mean of the Overall SarQoL® score was significantly higher than those of the SF-36 Physical Component Summary (p = 0.005), the EQ-5D Utility Index (p < 0.001) and the Euroqol visual analogue scale (p = 0.003).
CONCLUSION: The first data available on the ability of the SarQoL® questionnaire to detect change over time indicates that the questionnaire has good responsiveness. This, together with the previously established psychometric properties, confirms that the SarQoL® questionnaire is a relevant instrument for the assessment of quality of life in sarcopenic populations.