Evaluation of 24-Hour Esophageal pH and Impedance Studies in Patients with Suspected Gastroesophageal Reflux

Abstract

Purpose: Patients with suspected gastroesophageal reflux disease (GERD) are often treated empirically with proton pump inhibitor (PPI) therapy based on their clinical symptoms. Patients who are unresponsive to therapy may then undergo testing with 24-hour esophageal pH testing to confirm or exclude the diagnosis of GERD. The purpose of this study is to determine whether patients referred for the evaluation of typical and atypical reflux symptoms had GERD by 24-hour esophageal pH and impedance testing performed off of acid suppressive therapy. Methods: A clinical database was searched for 24-hour pH/impedance studies performed off of acid suppressive therapy between 2006 and 2011. Patients referred for evaluation had typical GERD symptoms (heartburn or acid regurgitation) or atypical symptoms (chest pain, chronic cough, hoarseness, dysphagia or dyspepsia). Many patients referred for evaluation were not responding clinically to a prescribed PPI. Patients were instructed to discontinue PPI at least one week prior to testing. A Johnson-DeMeester score of ≥22 was considered diagnostic for GERD by pH testing. An abnormal impedance study was defined as > 73. Categorical data was expressed as percentages and continuous data as means and standard deviation. Fisher exact tests and Student's t-test were used to analyze data. A p-value ≤ 0.05 was considered statistically significant. Results: 348 patients were identified (mean age of 47 ± 13 years; 55% were male, and 62% were Caucasians). The majority of patients (96%) were empirically treated with PPI prior to testing, of which 68% were on daily dosage and 32% on twice daily dosage. On 24-hour esophageal pH testing, the majority (72%) had a normal Johnson-DeMeester score. Among patients who had an abnormal pH score, 58% had typical GERD symptoms and 42% had atypical symptoms (P=0.023). Significantly more males had an abnormal pH score compared to females (34% versus 20%, P=0.004). There were no significant differences in race or age of patients with normal and abnormal pH testing. On impedance testing, 21.6% patients had an abnormal test. Of patients who had a normal 24-hour pH test, 87% had a normal impedance test. Of patients who had an abnormal 24-hour pH test, 44% had an abnormal impedance test (Kappa = 0.331, P<0.001). Conclusion: Most patients referred for GERD testing after failing empiric PPI therapy had a normal 24 hour pH/impedance study off of acid suppressive therapy. In these patients, an alternative diagnosis should be considered.