Diagnostic value of the Reflux Disease Questionnaire in general practice.

OBJECTIVES This study determined the diagnostic and therapeutic response of the Reflux Disease Questionnaire (RDQ) using the symptom association probability (SAP) as reference. In addition, the RDQ's construct validity and its relationship to quality of life (QOL) were ascertained. METHODS Seventy-four patients with GORD symptoms (age 51 years (22-78); male 62%) derived from primary care completed the RDQ, GSRS and QOLRAD before and after a 2 weeks' course of esomeprazole 40 mg daily. The SAP was determined by a 24-hour pH recording before PPI treatment. The diagnostic abilities of the RDQ (total and 4 dimensions scores) were assessed with the area under the curve (AUC) of a receiver operating curve. RDQ scores before and after PPI treatment were compared with Wilcoxon tests. Multiple linear regressions assessed the RDQ's construct validity (GSRS) and relationship to QOL (QOLRAD). RESULTS The AUCs were low for all RDQ dimensions (AUC <0.6). In the SAP-positive patients all RDQ dimensions improved (p < 0.0001) while the scores of the SAP negatives did not (heartburn p < 0.01; GORD and total score p < 0.05; regurgitation and dyspepsia n.s.). The RDQ was related to the total and reflux GSRS dimensions while the food and drink QOL dimension was linearly associated with the RDQ. CONCLUSIONS The RDQ is a valid and reliable questionnaire with excellent construct validity and a good relationship to QOL. The diagnostic value of the RDQ in primary care is limited, but combination with an additional PPI treatment course might improve the RDQ's ability to discriminate GORD patients according to their SAP outcome.