Clinical utility of small intestinal bacterial overgrowth (SIBO) testing in guiding management of gas-bloat symptoms after antireflux surgery.

Background: Gas-bloat symptoms are common after antireflux surgery (ARS) and typically attributed to impaired gas venting from surgical changes. However, small intestinal bacterial overgrowth (SIBO), potentially linked to chronic PPI use, may also contribute. Despite this, the role of SIBO in post-ARS bloating remains underexplored. This study aimed to assess the utility of SIBO testing in patients with persistent gas-bloat symptoms after ARS.

Methods: Patients with persistent bloating after primary ARS were offered SIBO breath testing and gastric emptying scintigraphy. Those with normal gastric emptying who completed testing were included. A gas-bloat score ≥ 4 on the GERD-HRQL questionnaire was considered severe. Outcomes were compared between SIBO-positive and SIBO-negative patients. SIBO-positive patients were treated with antibiotics and reassessed.

Results: Among 71 patients with postoperative gas-bloat symptoms following ARS, 40 (56.3%) tested positive for SIBO. Compared to SIBO-negative patients, SIBO-positive patients had significantly higher postoperative gas-bloat scores (median [IQR] 4.0 [4.0-5.0] vs 3.0 [3.0-4.0], p < 0.001) and more frequent severe symptoms (77.5% vs 41.9%, p = 0.003), despite similar GERD-HRQL total scores, acid exposure, and satisfaction (p > 0.05). Following antibiotic therapy, severe gas-bloat symptoms improved markedly (77.5% to 23.1%, p < 0.001), with corresponding reductions in gas-bloat scores (4.0 [4.0-5.0] to 2.0 [1.0-3.0], p < 0.0001) and GERD-HRQL total scores (10.5 [7.0-19.0] to 5.0 [2.0-14.0], p = 0.002). After treatment, SIBO-positive patients had significantly better GERD-HRQL total scores than SIBO-negative patients (5.0 [2.0-14.0] vs 15.0 [7.0-26.0], p < 0.0001). Satisfaction also increased from 42.5% to 69.2% (p = 0.021). Post-treatment, SIBO-positive patients had significantly lower gas-bloat (p = 0.004), lower regurgitation scores (p = 0.003), and higher satisfaction (p = 0.015) than SIBO-negative patients.

Conclusion:  SIBO was present in over half of patients with persistent bloating after ARS and was associated with more severe symptoms. Antibiotic treatment led to substantial symptom improvement and increased satisfaction. These findings suggest that SIBO testing may guide targeted therapy and improve outcomes in selected patients following antireflux surgery.