Symptom overlap in patients with upper gastrointestinal complaints in the Canadian confirmatory acid suppression test (CAST) study: further psychometric validation of the reflux disease questionnaire

SummaryBackground The reflux disease questionnaire (RDQ) is a short, patient‐completed instrument.Aims To investigate the psychometric characteristics of the RDQ in patients with heartburn‐predominant (HB) and non‐heartburn predominant (NHB) dyspepsia.Methods HB (n = 388) and NHB (n = 733) patients were randomized to esomeprazole 40 mg daily or twice daily for 1 week, followed by 3 weeks of esomeprazole 40 mg daily.Results High factor loadings (0.78–0.86) supported the ‘regurgitation’ dimension of the RDQ. Overlapping factor loadings in the ‘heartburn’ and ‘dyspepsia’ dimensions suggested symptom overlap. All dimensions demonstrated high internal consistency (Cronbach’s alpha: 0.79–0.90). Intra‐class correlation coefficients over 4 weeks were good (0.66–0.85). The RDQ showed good responsiveness over 4 weeks of treatment, with high effect sizes (≥0.80). Moderate or large symptom improvements were reported by 90% and 77% of HB and NHB patients, respectively, following treatment. Patients who responded to acid suppression also experienced symptom benefits in all RDQ dimensions.Conclusions The RDQ is reliable, valid and responsive to change in HB and NHB patients. The symptom overlap is important but need not play a major role in determining treatment strategy as both patient groups benefited from proton pump inhibitor treatment.

Symptom overlap in patients with upper gastrointestinal complaints in the Canadian confirmatory acid suppression test (CAST) study: further psychometric validation of the reflux disease questionnaire Journal Articles