Is the reflux disease questionnaire useful for identifying GERD according to the Montreal definition?

Background: Scales for aiding physicians diagnose gastro-oesophageal reflux disease (GERD) have not been evaluated in terms of their ability to discriminate between troublesome symptoms (TS) and non-troublesome symptoms (NTS). Our objective is to evaluate the ability of the Reflux Disease Questionnaire (RDQ) to identify GERD according to referral of TS, in patients without previous proton pump inhibitor (PPI) treatment and in patients on PPI treatment. Methods: Patients consulting physicians because of heartburn or acid regurgitation were recruited at 926 primary-care centres in Spain. They were asked to complete several questionnaires including the RDQ, and to define which of their symptoms were troublesome. Information on drug treatment was collected by the physician. We performed a receiver operating characteristic (ROC) curve analysis to ascertain the RDQ's optimum cut-point for identifying TS. Results: 4574 patients were included, 1887 without PPI and 2596 on PPI treatment. Among those without PPI treatment, 1722 reported TS. The area under the curve (AUC) was 0.79 for the RDQ, and the optimum RDQ cut-point for identifying TS was 3.18 (sensitivity, 63.2%; specificity, 80.2%). A total of 2367 patients on PPI treatment reported TS, and the optimum RDQ cut-off value was 3.06 (sensitivity, 65.4%; specificity, 71.8%). Conclusions: An RDQ score higher than 3 shows good sensitivity and specificity for differentiating TS from NTS among patients without PPI or on PPI treatment. The RDQ is useful in primary care for diagnosis of GERD based on the Montreal definition.