The Reflux Disease Questionnaire: a measure for assessment of treatment response in clinical trials

Michael Shaw¹ , John Dent² , Timothy Beebe³ , Ola Junghard⁴ , Ingela Wiklund⁴ , Tore Lind⁴ and Folke Johnsson⁵

¹Park Nicollet Clinic and University of Minnesota Medical School, Minneapolis, MN 55416-2699, USA

²Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia

³Mayo Clinic College of Medicine, Rochester, MN 55905, USA

⁴AstraZeneca R&D, SE-431 83 Mölndal, Sweden

⁵University of Lund, SE-221 00 Lund, Sweden

author email corresponding author email

Health and Quality of Life Outcomes 2008, 6:31doi:10.1186/1477-7525-6-31


Published:	30 April 2008

Abstract

Background

Critical needs for treatment trials in gastroesophageal reflux disease (GERD) include assessing response to treatment, evaluating symptom severity, and translation of symptom questionnaires into multiple languages. We evaluated the previously validated Reflux Disease Questionnaire (RDQ) for internal consistency, reliability, responsiveness to change during treatment and the concordance between RDQ and specialty physician assessment of symptom severity, after translation into Swedish and Norwegian.

Methods

Performance of the RDQ after translation into Swedish and Norwegian was evaluated in 439 patients with presumed GERD in a randomized, double-blind trial of active treatment with a proton pump inhibitor.

Results

The responsiveness was excellent across three RDQ indicators. Mean change scores in patients on active treatment were large, also reflected in effect sizes that ranged from a low of 1.05 (dyspepsia) to a high of 2.05 (heartburn) and standardized response means 0.99 (dyspepsia) and 1.52 (heartburn). A good positive correlation between physician severity ratings and RDQ scale scores was seen. The internal consistency reliability using alpha coefficients of the scales, regardless of language, ranged from 0.67 to 0.89.

Conclusion

The results provide strong evidence that the RDQ is amenable to translation and represents a viable instrument for assessing response to treatment, and symptom severity.