Gastroesophageal reflux disease is not associated with disease severity in patients with Mycobacterium avium complex lung infection

Background Mycobacterium avium complex (MAC) pulmonary infection was previously associated with gastroesophageal reflux disease (GERD), although the effects of GERD on MAC outcomes remains unclear. The goal of this study was to assess the prevalence of GERD in patients with MAC pulmonary infection and its association with clinical outcomes. Methods This was a retrospective study of adult patients with confirmed MAC pulmonary infection who underwent ambulatory pH monitoring. Pathologic acid reflux was defined as a total distal acid exposure time ≥6 %. Adjunctive esophageal tests including esophagogastroduodenoscopy, barium esophagram, and high-resolution manometry were assessed. The primary outcomes were pulmonary function testing and treatment of MAC pulmonary infection. Results Of 132 included patients, 35 (26.5 %) had an acid exposure time ≥6 %. There were no differences between patients with and without pathologic acid reflux by AET and pulmonary function tests including FEV1 absolute (1.79 vs. 1.83 L, p = 0.68), FEV1 % predicted (78.6 vs. 78.0 %, p = 0.94), FEV1/FVC % predicted (71.1 vs. 68.0 %, p = 0.38), or DLCO % predicted (66.0 vs. 79.0 %, p = 0.097). Additionally, there were no differences in MAC pulmonary infection outcomes including antimicrobial treatment, duration, or lobectomy. Findings on adjunctive esophageal testing did not associate with outcomes by pulmonary function tests or treatment of MAC pulmonary infection. Conclusions The prevalence of GERD in patients with MAC pulmonary infection based on ambulatory pH monitoring was 26.5 %. MAC pulmonary infection with GERD was not associated with worse outcomes and further study is needed to assess the impacts of GERD on MAC pulmonary infection.