International validation of ReQuest in patients with endoscopy-negative gastro-oesophageal reflux disease

Background: Reflux Questionnaire (ReQuest), a newly developed gastro-oesophageal reflux disease-sensitive scale, can be used to reliably evaluate the effect of treatment on gastro-oesophageal reflux disease symptoms. Aim: International validation of this scale, in patients suffering from endoscopy-negative gastro-oesophageal reflux disease. Methods: In this open, multicentre and multinational clinical trial 840 endoscopy-negative gastro-oesophageal reflux disease patients received pantoprazole 20 mg daily for 28 days. The long and short versions of ReQuest were completed both in the pre-treatment and treatment phases. For scale development an item reduction analysis was performed. Internal consistency, test-retest reliability and responsiveness were calculated for psychometric analysis. Construct validity was evaluated by comparison with the Gastrointestinal Symptom Rating Scale and the Psychological General Well-being questionnaire by means of correlation coefficients. Results: Factor analyses confirmed the content validity of both long and short version of ReQuest. Psychometric calculations proved high internal consistency (Cronbach's alpha: 0.9), test-retest reliability [Intraclass Correlation Coefficient: 0.9 (long vs. long) and 0.8 (short vs. short)], and responsiveness (Responsiveness Index 320.3) of the scale, for which also good construct validity was achieved (correlation coefficient: Gastrointestinal Symptom Rating Scale -0.6; Psychological General Well-being -0.4). Conclusion: ReQuest proved valid, reliable, and responsive in this multinational clinical trial to evaluate treatment response in endoscopy-negative gastro-oesophageal reflux disease patients.