Psychometric validation of the Japanese translation of the Quality of Life in Reflux and Dyspepsia questionnaire in patients with heartburn
The purpose of this study was to document the psychometric characteristics of the Japanese translation of the Quality of Life in Reflux and Dyspepsia (QOLRAD-J) questionnaire in patients with heartburn. Patients with heartburn or acid regurgitation and healthy subjects completed the QOLRAD-J and the Japanese version of the Short-Form 36-Item (SF-36) Health Survey. Overall, 224 patients with heartburn and 24 healthy subjects entered the study; 72% of patients had heartburn 1–3 days per week; 84% reported their symptoms as mild. Psychometric validation of the QOLRAD-J showed that factor loadings were >0.55 for 19 of the 25 items in the five-factor structure. Pearson correlation coeffi-cients for inter-item correlations in the same domain were all >0.30, demonstrating reliability. The internal consistency reliability was good (Cronbach's α, 0.83–0.94). Inter-item correlations between domains ranged from 0.70 to 0.80, indicating strong correlations. Each QOLRAD-J domain correlated positively with at least five of the eight SF-36 domains (Pearson r ≥ 0.3). Negative correlations between the QOLRAD-J and patient-reported frequency and severity of heartburn symptoms indicated decreasing quality of life with increasing symptoms. All domains of the QOLRAD-J were able to differentiate between groups of patients whose health status differed according to severity and frequency of heartburn, thus confirming the known-groups validity. Patients with heartburn had clinically significant decreases in SF-36 scores compared with the Japanese general population. The psychometric characteristics of the QOLRAD-J demonstrated good validity and reliability. The QOLRAD-J can be used to assess quality of life in Japanese patients with heartburn.