Prolonged 2-Day Esophageal pH-Metry with Impedance Monitoring Improves Symptom-Reflux Association Analysis

BACKGROUND: The day-to-day variability in the number of reflux episodes and symptoms of gastro-esophageal reflux disease is high; therefore, the assessment of reflux disease based on 24-h monitoring may be inaccurate. AIMS: The aim of the study was to compare prolonged (48 h) and standard (24 h) pH-impedance monitoring (pH-MII). METHODS: Fifty-four consecutive patients with typical and atypical reflux symptoms underwent 48-h pH-MII. Acid exposure time (AET), total number of reflux episodes (TR), number of symptoms, and symptom association probability (SAP) were analyzed after the first 24 h and compared with the results obtained during 48 h of monitoring. RESULTS: The differences between the fractions of patients with normal and abnormal total AET and TR on both days were not significant. The percentage of patients with positive SAP was 57.9 % at 24 h and 71.9 % at 48 h (difference: 14.81 %, 95 % CI 0.7–21.29, P < 0.05). There were ten patients (10/54, 18.5 %) with positive SAP after 48 h that had been negative in the first 24 h. In comparison to 24 h monitoring, patients reported a significantly increased number of various symptoms correlated with reflux after 48 h. CONCLUSIONS: Extending pH-MII monitoring to 48 h does not improve the detection of abnormal acid exposure. However, it does increase the fraction of patients with positive symptom-reflux association by as much as 18.5 %.