Objectives: The gastroesophageal reflux disease questionnaire (GerdQ) is a validated questionnaire that identifies patients with gastroesophageal reflux disease (GERD). The aim of this study was to prospectively evaluate the association between GerdQ scores and 48-h wireless pH recording in patients studied either on or off acid suppression. Methods: Demographics, symptoms, acid suppressant use, and GerdQ scores were obtained from consecutive patients referred for wireless pH testing; 48-h pH data and endoscopic findings were recorded. Multivariate logistic regression models controlling for age, gender, and body mass index (BMI) were used to evaluate the association between GerdQ scores, acid reflux, and symptom association probability (SAP) scores. Results: Wireless pH-metry was completed in 180 patients off proton pump inhibitor (PPI) (mean (s.d.) age, 50 (14) years; BMI, 28.08 (6.87) kg/m 2) and 178 patients on PPI (mean (s.d.) age, 52 (14) years; BMI, 29.00 (6.90) kg/m 2). Abnormal acid exposure was noted in 26% of patients on and 61% off PPI therapy. The odds of an abnormal study were 5.04 (95% confidence interval (CI), 3.14-8.11) times greater in patients studied off PPI therapy compared with patients studied on PPI therapy. The odds ratio of the SAP being >95% was 5.69 (95% CI, 3.36-9.64; P<0.001) for patients studied off PPI therapy compared with on PPI therapy. The mean (s.d.) GerdQ score was 7.48 (4.53) in patients on PPI therapy and 9.11 (1.25) in patients off PPI therapy (P<0.001). The odds of having an abnormal pH study was 1.08 (95% CI, 0.99-1.16; P=0.07) in patients studied off PPI therapy and 1.00 (95% CI, 0.92-1.08; P=0.94) in patients on PPI therapy for each point increase on the GerdQ. The odds of an abnormal SAP 95% in patients studied off PPI therapy was 1.18 (95% CI, 1.09-1.28; P<0.001) and 1.10 (95% CI, 1.01-1.21; P<0.03) in patients studied on PPI therapy for each point increase in the GerdQ score. Conclusions: Higher GerdQ scores were predictive of an abnormal pH study in patients studied off PPI therapy. Compared with wireless pH capsule monitoring, the GerdQ has only modest sensitivity and specificity at diagnosing acid reflux and thus cannot be recommended as a screening tool for GERD.
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