Patients with gastrointestinal esophageal reflux disease (GERD) have more than three times the risk of developing nontuberculous mycobacterial pulmonary disease (NTM-PD), compared with those without GERD, according to a population-based retrospective cohort study.
“GERD is a common comorbidity of nontuberculous mycobacterial pulmonary disease [but] whether GERD is associated with an increased risk of developing NTM-PD is unknown,” Hayoung Choi, MD, PhD, Hallym University, Seoul, Republic of Korea, and colleagues reported.
Dr. Choi added in an email. “What needs to be understood is that GERD increases health care utilization in patients with NTM pulmonary disease; hence, clinicians who treat patients with NTM pulmonary disease need to be aware of the burden of GERD and treat the gastrointestinal illness simultaneously,” he added.
The study was published online in the journal CHEST.
Sample cohort
Data from the Korean National Health Insurance Service-National Sample Cohort between 2002 and 2015 were used to assess the impact of GERD on NTM-PD. The incidence and risk of NTM-PD were compared between 17,424 patients with GERD and 69,000 patients without GERD in a matched cohort. GERD was defined as patients having received more than 3 months of proton pump inhibitors (PPIs).
During a median follow-up of 5.1 years, the age- and sex-adjusted incidence of NTM-PD was significantly higher in the GERD cohort, at a rate of 34.8/100,000 person-years, than in the matched cohort, at a rate of only 10.5/100,000 person-years (P < .001), the authors reported.
As for risk factors for NTM-PD, being 60 years of age and older was associated with a 3.5-times higher risk of NTM-PD at an adjusted hazard ratio of 3.57 (95% confidence interval, 1.58-8.07), while bronchiectasis was associated with over an 18-times higher risk of NTM-PD in the GERD cohort at an adjusted HR of 18.69 (95% CI, 6.68-552.28). Those with GERD who developed NTM-PD had higher all-cause and respiratory disease–related emergency department visits or hospitalizations compared with patients with GERD who did not develop NTM-PD (P = .011), the investigators noted.
As the authors pointed out, the incidence of NTM-PD in the Korean population ranged from 6 to 19 cases/100,000 between 2008 and 2016; thus, the burden of incident NTM-PD associated with GERD appears to be considerable. As Dr. Choi explained, a combination of three factors influenced the development of NTM infections. The first is environmental, from water source, climate, or region; the second is patient influences, including such factors as immunodeficiency and comorbidities (including bronchiectasis); and the third is microbiological factors, including various NTM species.
Bile aspirating into the lung during GERD may be another possible pathway, as the authors suggested. Even if acid secretion is suppressed by PPI treatment in patients with GERD, NTM-PD may be induced or aggravated through mechanisms such as bile reflux. The fact that patients over the age of 60 were more prone to develop NTM-PD suggests that a decrease in gastric emptying and increased micro-aspiration or reflux associated with impaired swallowing (which are more common in elderly patients) may also be at play.
“Bronchiectasis is also a very well known risk factor for NTM pulmonary disease,” Dr. Choi emphasized. Thus, he recommends clinicians carefully observe clinical, radiological, and microbiological changes to detect NTM pulmonary disease when managing patients with bronchiectasis.
“The results of the present study have several potential clinical implications,” Dr. Choi and colleagues observed. First, NTM-PD should be suspected when new-onset worsening of respiratory symptoms develops during regular follow-up in patients with GERD. Second, because results indicate that older age and bronchiectasis significantly increase the risk of NTM-PD, “more active strategies (e.g., screening of symptoms and regular chest x-rays)” might be helpful in patients with GERD and these risk factors, the authors suggested. Because patients with GERD who developed NTM-PD had more respiratory disease–related ED visits and hospitalizations than those who did not develop NTM-PD, when GERD and NTM-PD are combined, clinicians should focus on the variations of respiratory symptoms, they suggested.
The authors cautioned, however, that because the study was one in a Korean population, studies in other countries and different ethnicities are needed before findings can be generalized.