Inflammatory bowel disease and risk of non-tuberculous mycobacterial pulmonary disease: a nationwide retrospective cohort study in Korea.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic immune-mediated disorder of the gastrointestinal tract, and patients with IBD are vulnerable to infections. Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is an infection of concern in immunocompromised individuals. However, data on the risk of NTM-PD in IBD patients are limited. This study aimed to investigate the association between IBD and the risk of NTM-PD using nationwide data in Korea. METHODS: We conducted a population-based matched cohort study involving 6,869 adults aged ≥20 years with IBD, using data acquired from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) database between 2002 and 2019. Multivariable Cox proportional hazards regression analyses were performed to estimate the hazard ratio (HR) and corresponding 95% confidence interval (CI) for incident NTM-PD in the overall IBD and IBD subtype cohorts (Crohn's disease and ulcerative colitis) compared to their respective 1:4 age-, sex-, and health insurance-matched cohorts. Fine-Gray subdistribution hazard models were additionally applied to account for competing risks. RESULTS: Over a median follow-up duration of 13.1 [interquartile range (IQR), 10.3-16.3] years, the incidence rate of NTM-PD was not significantly different, showing 54.82 and 43.21 per 100,000 person-years (PY) in the overall IBD and matched cohorts, respectively. In multivariable Cox-regression analysis, the risk of NTM-PD was not significantly increased in the IBD cohort compared to the matched controls (adjusted HR =1.12, 95% CI: 0.82-1.54). Also, in Fine-Gray model, the risk of NTM-PD was not significantly increased in the IBD cohort compared to the matched controls (adjusted HR =1.16, 95% CI: 0.85-1.59). Neither Crohn's disease nor ulcerative colitis was associated with increased risk of NTM-PD (adjusted HR =0.98, 95% CI: 0.52-1.84 for Crohn's; adjusted HR =1.26, 95% CI: 0.88-1.81 for ulcerative colitis vs. respective matched cohorts). CONCLUSIONS: In this nationwide, large, longitudinal study, IBD was not associated with increased risk of NTM-PD.