S1911 Epidemiology of Gastroesophageal Reflux Disease and Esophagitis: the Systematic Investigation of Gastrointestinal Diseases in China (SILC) Study

Introduction: Nonacid reflux has been shown to be able in inducing reflux symptoms in gastroesophageal reflux disease (GERD) patients. Non-erosive reflux disease (NERD) and erosive esophagitis (EE) are the most frequent phenotypic presentations of GERD. Aim: To evaluate symptom association probability (SAP) in patients with NERD and EE. Methods: We evaluated 44 patients with EE (26M, median age 48; range 23-73 yrs), 173 with NERD (67M, median age 49; range 18-78 yrs) and 48 controls (22M, median age 44; range 2277) using multichannel intraluminal impedance and pH while off-PPI therapy. All patients had typical reflux symptoms. We measured distal esophageal acid exposure time (AET), number of impedance-detected reflux episodes (acid, nonacid) and symptom association probability (SAP; positive if ≥95%). Results: Symptom-reflux association with SAP in EE and NERD patients is shown in the Figure below. Out of 35 (75%) EE patients with an abnormal AET, 33 (75%) had a positive SAP. Twenty-seven (61%) patients had a positive SAP for acid reflux only, 2 (5%) for nonacid reflux only and 4 (9%) for both. Among the 8 (18%) patients with a normal AET and a positive SAP, 3 (7%) had a positive SAP for nonacid reflux only, 2 (5%) for acid reflux only and 3 (7%) for both. Out of 72 (42%) NERD patients with an abnormal AET, 64 (37%) had positive SAP. Fifty-two (31%) patients had a positive SAP for acid reflux only, 8 (5%) for nonacid reflux only and 6 (3%) for both. Among the 101 (58%) patients with a normal AET, 59 (34%) had a positive SAP. Twentytwo (13%) patients had a positive SAP for nonacid reflux only, 23 (13%) for acid reflux only and 14 (8%) for both. Conclusions: Nonacid reflux clearly contributes to provoke reflux symptoms in both NERD and EE patients. The increased percentage of NERD patients whose symptoms are related to nonacid reflux could be due to the higher sensitivity of these patients to stimuli different from acid.