[Validation of the Reflux Disease Questionnaire (RDQ) and Gastrointestinal Impact Scale (GIS) in patients with gastroesophageal reflux disease in the Spanish population].Gastroenterol Hepatol. 2009 Apr; 32(4):264-73.GH
To assess the feasibility, reliability, validity and sensitivity of changes in the Reflux Disease Questionnaire (RDQ) and the Gastrointestinal Impact Scale (GIS).
MATERIAL AND METHODS
An observational, prospective, multicenter study was conducted in primary care centers on two visits (baseline and 16 days later) in a sample of patients with a diagnosis of gastroesophageal reflux disease (GERD) or suspicion of GERD requiring a therapeutic intervention (sensitivity to change group, n=230) and in another sample of patients with clinically controlled GERD (reliability group, n=51).
The RDQ questionnaire and GIS scale, both overall and for each domain, showed a Cronbach's alpha of greater than or equal to 0.70. All RDQ domains and the total score, as well as the total GIS score and impact dimension, showed a high correlation between the baseline evaluation and that performed 16 days later in stable patients. The RDQ and GIS showed very high correlations between the total scores and those of the quality of life in reflux and dyspepsia (QOLRAD) (-0.73 and 0.80, respectively), a reflux- and dyspepsia-specific quality of life scale, and a high correlation with the gastrointestinal symptoms rating scale (GSRS) (0.54 and -0.55, respectively), a general scale of gastrointestinal symptoms. Both the RDQ questionnaire and the GIS scale showed significant changes with a high effect size on improvement responses.
The RDQ and GIS questionnaires show very good psychometric properties, making them suitable for use in primary care.