Reflux characteristics of 113 GERD patients with abnormal 24-h multichannel intraluminal impedance-pH tests

OBJECTIVE: To analyze reflux parameters by means of combined multichannel intraluminal impedance and pH (MII-pH) monitoring in patients with gastroesophageal reflux disease (GERD) symptoms off medication, and to find the reflux characteristics of Chinese GERD patients and the influences of gender, age, body posture, and body mass index (BMI) on gastroesophageal reflux (GER). METHODS: Between Dec. 2008 and May 2014, 125 patients with typical GERD symptoms were subjected to 24-h MII-pH monitoring. Twelve patients with normal MII-pH profiles were not considered for analysis. The reflux parameters of 113 GERD patients with abnormal MII-pH results were analyzed. RESULTS: (1) DeMeester scores were above the normal range in 46.90% (53/113) of GERD patients. Weakly acidic refluxes were prevalent in GERD patients, and the frequency of abnormal weakly acidic reflux was 75.22% (85/113). The frequencies of abnormal symptom index (SI) and symptom association probability (SAP) were 19.47% (22/113) and 14.16% (16/113), respectively. (2) The frequencies of DeMeester scores, the %time at pH<4, and the numbers of reflux episodes and of long reflux episodes >5 min were significantly higher in male patients than in female patients. (3) The %time at pH<4 was much higher during upright periods than during supine periods. During supine periods, 31.86% (36/113) of GERD patients had delayed bolus clearance time, compared with 19.47% (22/113) during upright periods. (4) The number of abnormal DeMeester scores, %time at pH<4, and the number of acid refluxes during upright periods were significantly higher in obese GERD patients than in GERD patients with a normal BMI. Overweight GERD patients also had many more acid refluxes during upright periods than GERD patients with a normal BMI. CONCLUSIONS: Weakly acidic refluxes were prevalent in Chinese GERD patients. The factors male, gender, upright position, obesity (BMI≥25), but not age, may increase the frequency and severity of GER.