Reflux Symptoms Associated With SIBO Test Positivity
Key Clinical Summary
- In an analysis of 177 patients who completed the PAGI-SYM questionnaire before lactulose breath testing, 76 (42.9%) tested positive for small intestinal bacterial overgrowth (SIBO).
- The reflux symptom domain differed between SIBO-positive and SIBO-negative patients (P=.025); bloating/gas, foregut/postprandial distress, and lower gastrointestinal domains did not.
- No symptom domain differed by intestinal methanogen overgrowth (IMO) status. The findings do not establish that symptoms alone can predict an individual patient’s test result.
Patients who tested positive for SIBO reported more reflux-type symptoms, but their bloating and gas scores did not differ significantly from those of patients who tested negative, according to a PAGI-SYM analysis presented at the American College of Gastroenterology Scientific Meeting by Veronica West, DO, of Temple University in Philadelphia, Pennsylvania.
Study Findings
The analysis included patients undergoing lactulose breath testing who completed the Patient Assessment of Upper Gastrointestinal Disorders Symptom Severity Index (PAGI-SYM) before testing. Investigators defined SIBO as a hydrogen rise greater than 20 parts per million above baseline within 90 minutes. Of 211 patients tested, 177 completed the questionnaire; 76 of those respondents (42.9%) were SIBO positive.
Investigators grouped symptoms into 4 domains: reflux; bloating/gas; foregut/postprandial distress; and lower gastrointestinal symptoms. Patients rated individual symptoms from 0 to 5. The researchers compared domain scores between SIBO-positive and SIBO-negative patients and performed similar analyses for IMO.
Only the reflux domain differed significantly by SIBO status (P=.025). Within that domain, heartburn (P=.018), reflux sensation (P=.012), and bitter taste (P=.031) were associated with SIBO positivity. Heartburn while lying down (P=.18) and reflux while lying down (P=.29) were not.
The bloating/gas (P=.27), foregut/postprandial distress (P=.89), and lower gastrointestinal (P=.30) domains showed no significant differences by SIBO status. No symptom domain differed between IMO-positive and IMO-negative patients.
Clinical Implications
Clinicians interpreting the findings should also distinguish SIBO from IMO: the investigators found no symptom-domain differences for IMO. The abstract does not provide the number of IMO-positive patients or the magnitude of the differences in symptom scores.
The authors concluded that baseline PAGI-SYM symptom burden was “generally not predictive of SIBO or IMO” on lactulose breath testing. They described the association between reflux-type symptoms and SIBO positivity as “limited but detectable,” while cautioning that a bloating-dominant profile may not reliably distinguish SIBO status.
The analysis suggests that symptom presentation alone offers limited guidance about whether lactulose breath testing will be positive for SIBO or IMO.
Reference: West V, Lakkaraju GCR, Parkman HP. Do symptoms predict SIBO? A PAGI-SYM domain analysis of patients undergoing lactulose breath testing. Abstract P2020. Presented at: American College of Gastroenterology. Nashville, Tennessee. October 12-14, 2026.
