PH Impedance vs. traditional pH monitoring in clinical practice: an outcome study.

Abstract

The addition of impedance to 24-h pH monitoring has allowed detection of weakly acidic reflux, but the extent to which pH-impedance (pH-MII) monitoring improves outcomes is unknown. This was a prospective observational study. Patients referred for pH or pH-MII monitoring completed a standardized questionnaire on improvement in the dominant symptom, their satisfaction, and treatment at 3 and 12months after the test during a telephone interview. A total of 184 patients (mean age, 52years, range, 19-82years; 35% with typical symptoms; and 89% tested off therapy) completed pH (n=92) or pH-MII monitoring (n=92) over a period of 15months. The two arms were similar in terms of demographic, clinical, and endoscopic variables. Ten patients in the pH-MII arm showed evidence of weakly acidic reflux disease. There was no difference in the percentage of patients in the pH and pH-MII monitoring arms who experienced improvement in their dominant symptom after 3 (58 vs. 63%; p=0.621) or 12months (66 vs. 70%; p=0.234), and the same was true for patient satisfaction. There were also no between-group difference in the use of proton pump inhibitors (PPIs) after 3 (63 vs. 68.5%; p=0.437) or 12months (47 vs. 60.5%; p=0.051). PPIs were prescribed more frequently after a positive test (p<0.001) although they were used by 45.6% of the negative patients. Only one patient underwent fundoplication. Two-thirds of patients undergoing pH-MII monitoring experience a positive outcome, similarly to what occurs after traditional pH monitoring. Physicians often pay little attention to the test results, especially if they are negative.