A Prospective Study to Compare a Symptom-Based Reflux Disease Questionnaire and Impedance-pH Monitoring for the Identification of Gastroesophageal Reflux Disease

Abstract

Purpose: The diagnosis of gastroesophageal reflux (GERD) remains problematic. Older questionnaires have suffered from low sensitivity/specificity and lack of comparison with pH-metry. The GerdQ is a validated, 6-item questionnaire developed to identify patients (Pts) with GERD. No study has compared GerdQ to impedance-pH monitoring. Our aim was to prospectively evaluate the association between GerdQ scores and parameters of impedance-pH monitoring in patients studied either on or off acid suppression. Methods: Consecutive patients referred for impedance-pH testing were eligible for inclusion. Demographics, symptoms, type, dose and frequency of acid suppressants were obtained. The GerdQ score was calculated as the sum of heartburn, regurgitation, upper abdominal pain, nausea, difficulty sleeping, and need for additional medication (total score 0-18). Impedance-pH data was analyzed according to standard criteria. A percent pH < 4.0 for > than 6.3% of the 24-hour period was considered abnormal. Multivariate logistic regression models controlling for age, gender, and BMI were used to evaluate the association between amplified Gerd-Q scores and abnormal levels of esophageal acid reflux and non-acid reflux. Results: During the 5 month study period impedance-pH monitoring was completed in 36 patients (aged 52±14 yrs; BMI=26.1±5.4; 83% women; 97% Caucasian). The mean duration of symptoms was 99±94 months. All patients completed the study. 2 patients were excluded from analysis because they did not fill out the questionnaire. The pH study was completed while on PPI in 59% of patients (25% qd; 65% bid). Abnormal acid exposure was noted in 20% of patients on PPI and 36% patients off PPI (p=0.31). Abnormal total acid and non-acid reflux was present in 25% of patients on PPI therapy and 21% of patients off PPI therapy (p=0.81). Controlling for age, gender, and BMI, no significant differences were found regarding the likelihood of an abnormal study for patients studied off PPI therapy compared to those studied while on PPI therapy. The mean Gerd-Q score was 9.14 in patients off PPI and 10.1 in patients on PPI (P=0.36). There was a tendency for the Gerd-Q to be more strongly associated with an abnormal pH study in patients studied off acid suppression, compared to on PPI therapy, although this did not reach statistical significance. Conclusion: The GerdQ is a fast and easy-to-perform questionnaire that may prove useful in diagnosing acid and or non-acid reflux. Confirming prior studies which used the wireless pH capsule, evaluating patients off PPI therapy is more likely to provide clinically useful information than evaluating patients on PPI therapy. Further analysis with a larger patient population is required to determine whether the GerdQ is an accurate measure of both acid and non-acid reflux.