Inhaled Corticosteroids and Non-Tuberculous Mycobacteria Risk in Patients with COPD

Background/Objectives: Inhaled corticosteroids (ICS) increase the risk of pneumonia caused by various pathogens in patients with chronic obstructive pulmonary disease (COPD). Treatment may also increase the risk of infection with non-tuberculous mycobacteria (NTM), although evidence remains limited. The aim of this study was to assess the association between ICS treatment and the risk of NTM isolation among patients with COPD. Methods: This retrospective register-based cohort study included patients with a specialist-verified COPD diagnosis between 2008 and 2021. ICS exposure was based on redeemed prescriptions during the year preceding the index date. Exposure was calculated as the mean daily budesonide-equivalent dose and categorized as none, low, medium, or high. A cause-specific Cox proportional hazards regression model with death as a competing risk was applied, adjusted for potential confounders. Sensitivity analyses included, among others, an inverse probability of treatment weighted model, and a time-dependent Cox regression model. Results: A total of 120,006 patients were included, with a median follow-up time of 4.9 years. During follow-up, 378 (0.32%) patients reached the primary endpoint. Medium- and high-dose ICS were associated with an increased hazard of NTM isolation, with hazard ratios of 1.39 (95% CI 1.06-1.88, p = 0.020) and 1.52 (95% CI 1.14-2.04, p = 0.005), respectively. This association remained significant for high-dose ICS across all sensitivity analyses. Conclusions: In patients with COPD, ICS treatment was associated with an increased and dose-dependent hazard of NTM isolation, particularly at high doses. High-dose ICS should, therefore, be prescribed with caution.