INTRODUCTION: Being an easy-to-use (eight items) quality of life questionnaire specific to GERD, the Reflux-Qual Short form (RQS) was developed for use in everyday practice. The purpose of this study was to assess the psychometric properties of the RQS. METHODS AND MATERIALS: The reliability of the RQS was measured by the Cronbach's alpha coefficient and its clinical validity by comparing the RQS score for increasing clinical severity groups. The RQS discriminative power was compared with that of the SF12. Sensitivity to change over time was measured by calculating effect-sizes. RESULTS: The reliability and validity of the questionnaire were assessed on a sample of 1195 patients. Its psychometric properties were very satisfactory: Cronbach alpha = 0.84; RQS score significantly reduced for the worst-affected patients; the discriminative power was up to 5 times higher when compared with the SF-12. Sensitivity to change over time, evaluated with 362 patients, showed highly significant differences between groups with different levels of clinical progression (P = 0.0001). CONCLUSION: The RQS is a quality of life measurement instrument specific to GERD which is short, reliable, valid, and sensitive to within and between-subject differences.
INTRODUCTION: Being an easy-to-use (eight items) quality of life questionnaire specific to GERD, the Reflux-Qual Short form (RQS) was developed for use in everyday practice. The purpose of this study was to assess the psychometric properties of the RQS. METHODS AND MATERIALS: The reliability of the RQS was measured by the Cronbach's alpha coefficient and its clinical validity by comparing the RQS score for increasing clinical severity groups. The RQS discriminative power was compared with that of the SF12. Sensitivity to change over time was measured by calculating effect-sizes. RESULTS: The reliability and validity of the questionnaire were assessed on a sample of 1195 patients. Its psychometric properties were very satisfactory: Cronbach alpha = 0.84; RQS score significantly reduced for the worst-affected patients; the discriminative power was up to 5 times higher when compared with the SF-12. Sensitivity to change over time, evaluated with 362 patients, showed highly significant differences between groups with different levels of clinical progression (P = 0.0001). CONCLUSION: The RQS is a quality of life measurement instrument specific to GERD which is short, reliable, valid, and sensitive to within and between-subject differences.