PURPOSE: Chronic gastric acid aspiration in the setting of esophageal disorders has been linked to an increased risk of nontuberculous mycobacterial (NTM) lung disease. We hypothesized that individuals with COPD who receive gastric acid suppression therapy are less likely to have NTM isolated from the airway.
METHODS: We identified all individuals at a single VA medical center with a diagnosis of spirometry-proven COPD from whom at least one respiratory mycobacterial culture was collected during a 5-year period ending December 2008. A multivariable logistic regression model was designed to determine if isolation of NTM from the airway is less likely in patients receiving acid suppression therapy in the form of a proton pump inhibitor (PPI) or an H2 receptor antagonist. Model covariates included age, COPD severity, ethnicity, mycobacterial species, and duration of acid suppressive treatment prior to culture.
RESULTS: Over the 5-year study period NTM was isolated from the respiratory tract of 57 individuals with spirometry-proven COPD while 111 COPD patients had respiratory mycobacterial cultures collected that remained negative. Ongoing use of acid suppression therapy-adjusted for age, COPD severity, and race-was associated with a trend toward a decreased likelihood of NTM isolation from the airway (OR 0.496, p=0.056). This association was not influenced by the duration of acid suppression therapy. In a separate model limited to those patients from whom NTM was isolated, acid suppression therapy was not associated with a decreased likelihood of clinically meaningful NTM lung disease, defined as meeting ATS guidelines for treatment or a physician's decision to treat.
CONCLUSIONS: Individuals receiving acid suppressive therapy appear to be less likely to have NTM isolated from respiratory samples than those not receiving acid suppression; however, this trend was not statistically significant. Furthermore, acid suppression therapy does not seem to reduce the likelihood of clinically meaningful NTM lung disease in COPD patients with positive cultures.
CLINICAL IMPLICATIONS: Airway susceptibility to NTM may be influenced by gastric acid suppression in patients with COPD.
DISCLOSURE: The following authors have nothing to disclose: Julie Philley, Chad Newton, John Battaile
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