Background: Inhaled corticosteroids (ICS) are commonly used to treat COPD and are associated with increased risk of pneumonia. The aim of this study was to assess if accumulated use of ICS is associated with a dose-dependent risk of a positive airway culture withPseudomonas aeruginosain patients with COPD.Methods: We conducted a multiregional epidemiological cohort study including Danish COPD patients followed in outpatient clinics during 2010–2017. ICS use was categorised based on accumulated prescriptions redeemed 365 days prior to cohort entry. Cox proportional hazard regression model was used to estimate the risk of acquiringP. aeruginosa. Propensity score matched models were used as sensitivity analyses.Results: A total of 21 408 patients were included in the study, of which 763 (3.6%) acquiredP. aeruginosaduring follow-up. ICS use was associated with a dose-dependent risk ofP. aeruginosa(low ICS dose: HR 1.38, 95% CI 1.03 to 1.84, p=0.03; moderate ICS dose: HR 2.16, 95% CI 1.63 to 2.85, p<0.0001; high ICS dose: HR 3.58, 95% CI 2.75 to 4.65, p<0.0001; reference: no ICS use). A propensity matched model confirmed the results (high ICS dose compared with no/low/moderate ICS dose: HR 2.05, 95% CI 1.76 to 2.39, p p<0.0001).Conclusion: Use of ICS in patients with COPD followed in Danish outpatient clinics was associated with a substantially increased and dose-dependent risk of acquiringP. aeruginosa. Caution should be taken when administering high doses of ICS in severely ill patients with COPD. These results should be confirmed in comparable cohorts and other settings.

Social distancing measures introduced on March 12, 2020, in Denmark during the COVID-19 pandemic may affect non–COVID-19 admissions for severe acute exacerbation of chronic obstructive pulmonary disease (s-AECOPD). We compared rates of s-AECOPD in a nationwide, observational, semi-experimental cohort study using data from all Danish inhabitants between calendar week 1 through 25 in 2019 and 2020. In a sub-cohort of patients with chronic obstructive pulmonary disease, we examined incidence of s-AECOPD, admissions to an intensive care unit, and all-cause mortality. A total of 3.0 million inhabitants aged ≥40 years, corresponding to 3.0 million person-years, were followed for s-AECOPD. In the social distancing period in 2020, there were 6,212 incidents of s-AECOPD, compared with 11,260 incidents in 2019, resulting in a 45% relative risk reduction. In the cohort with chronic obstructive pulmonary disease (n = 16,675), we observed a lower risk of s-AECOPD in the social distancing period (subdistribution hazard ratio (HR) = 0.34, 95% confidence interval (CI): 0.33, 0.36; absolute risk: 25.4% in 2020 and 42.8% in 2019). The risk of admissions to an intensive care unit was reduced (subdistribution HR = 0.64, 95% CI: 0.47, 0.87), as was all-cause mortality (HR = 0.83, 95% CI: 0.76, 0.90). Overall, the social distancing period was associated with a significant risk reduction for hospital admittance with s-AECOPD.

Due to frequent exacerbations, many patients with chronic obstructive pulmonary disease (COPD) are exposed to oral corticosteroids (OCS), which may be thrombogenic. We evaluated the risk of hospitalisation with venous thromboembolism (VTE) and death in patients with acute exacerbation of COPD (AECOPD) treated with long and short OCS regimens. In this nationwide cohort study of 30,473 COPD outpatients treated for AECOPD, we compared the risk of VTE hospitalisation and all-cause mortality within 6 months in OCS dose of >250 mg vs. ≤250 mg. A multivariable Cox proportional hazard regression was used to estimate the risk. The incidence of VTE hospitalisations was 0.23%. A long OCS treatment course was associated with an increased risk of VTE compared to a short course (hazard ratio (HR) 1.69, [95% confidence interval (CI) 1.05 to 2.72], p < 0.031). A higher risk of all-cause mortality was seen in the group of COPD patients treated with a long OCS course (HR 1.71, [95% CI 1.63 to 1.79], p < 0.0001). The risk of reported VTE hospitalisation was higher among AECOPD patients treated with long courses of OCS, but the absolute risk was low, suggesting under-reporting of the condition.

Background: Inhaled corticosteroids (ICS) are widely used in chronic obstructive pulmonary disease (COPD), despite the known risk of severe adverse effects including pulmonary infections. Research Question: Our study investigates the risk of acquiring a positive Haemophilus influenzae airway culture with use of ICS in outpatients with COPD. Study Design and Methods: We conducted an epidemiological cohort study using data from 1 January 2010 to 19 February 2018, including 21,218 outpatients with COPD in Denmark. ICS use 365 days prior to cohort entry was categorised into low, moderate, and high, based on cumulated ICS dose extracted from a national registry on reimbursed prescriptions. A Cox proportional hazards regression model was used to assess the future risk of acquiring H. Influenzae within 365 days from cohort entry, and sensitivity analyses were performed using propensity score matched models. Results: In total, 801 (3.8%) patients acquired H. Influenzae during follow-up. Use of ICS was associated with a dose-dependent increased risk of acquiring H. Influenzae with hazard ratio (HR) 1.2 (95% confidence interval (CI) 0.9–1.5, p value = 0.1) for low-dose ICS; HR 1.7 (95% CI 1.3–2.1, p value < 0.0001) for moderate dose; and HR 1.9 (95% CI 1.5–2.4, p value < 0.0001) for high-dose ICS compared to no ICS use. Results were confirmed in the propensity-matched model using the same categories. Conclusions: ICS use in outpatients with COPD was associated with a dose-dependent increase in risk of isolating H. Influenzae. This observation supports that high dose ICS should be used with caution.

Patients with severe chronic obstructive pulmonary disease (COPD) experience frequent acute exacerbations and require repeated courses of corticosteroid therapy, which may lead to adverse effects. Methotrexate (MTX) has anti-inflammatory properties. The objective of this study was to describe the risk of COPD exacerbation in patients exposed to MTX. In this nationwide cohort study of 58,580 COPD outpatients, we compared the risk of hospitalization-requiring COPD exacerbation or death within 180 days in MTX vs. non-MTX users in a propensity-score matched study population as well as an unmatched cohort, in which we adjusted for confounders. The use of MTX was associated with a reduction in risk of COPD exacerbation in the propensity-score matched population at 180 days follow-up (HR 0.66, CI 0.66–0.66, p < 0.001). Similar results were shown in our sensitivity analyses at 180-day follow-up on unmatched population and 365-day follow-up on matched and unmatched population (HR 0.76 CI 0.59–0.99, HR 0.81 CI 0.81–0.82 and HR 0.92 CI 0.76–1.11, respectively). MTX was associated with a lower risk of COPD exacerbation within the first six months after study entry. The finding seems biologically plausible and could potentially be a part of the management of COPD patients with many exacerbations.