Development and validation of a patient-reported outcome instrument in partial responders to proton pump inhibitors

Abstract

Objective. The Reflux Symptom Questionnaire 7-day recall (RESQ-7) was developed, in line with the US Food and Drug Administration (FDA) guidelines, to address the need for a patient-reported outcome (PRO) instrument assessing symptoms specifically in patients with gastroesophageal reflux disease (GERD) who are only partially responsive to proton pump inhibitor (PPI) therapy. Materials and methods.The RESQ-7 was constructed using patient interviews and expert consensus. The instrument was psychometrically validated in a clinical trial setting in patients with persistent GERD symptoms despite PPI therapy. Results. Evaluation of content validity yielded a 13-item structure for the RESQ-7, incorporating symptoms overlooked by existing GERD questionnaires, such as hoarseness, cough, difficulty swallowing and burping. Principal component analysis suggested a four-domain structure. All domains had a high inter-item correlation (Cronbach's α lower 95% confidence limits: 0.77–0.87 for intensity; 0.72–0.82 for frequency). Test–retest reliability was fair-to-good or excellent (intraclass correlation coefficient lower 95% confidence limits: 0.70–0.78 for intensity; 0.65–0.75 for frequency). Convergent and discriminant validity were confirmed by correlation comparisons with the Gastrointestinal Symptom Rating Scale. Discussion.The RESQ-7 demonstrated good content validity and psychometric properties in patients with GERD and a partial response to PPIs. The weekly recall makes the RESQ-7 appropriate for use in routine clinical care. The authors believe that it is the first instrument to be developed specifically for patients with a partial response to PPI therapy in line with FDA guidelines on PROs (ClinicalTrials.gov identifier: NCT00703534).