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 comparing data from all Danish inhabitants between calendar week 1 through 25 in 2019 and 2020. In a sub-cohort of COPD patients, we examined incidence of s-AECOPD, admissions to 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 to 11,260 incidents of s-AECOPD in 2019, resulting in a 45% relative risk reduction. In the COPD cohort (N=16,675), we observed a lower risk of s-AECOPD with the social distancing period (subdistribution hazard ratio [sHR] 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 intensive care unit was reduced (sHR 0.64, CI: 0.47, 0.87) as was all-cause mortality (normal HR 0.83, CI: 0.76, 0.90). Overall, the social distancing period was associated with a significant risk reduction for hospital admittance with s-AECOPD.

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BackgroundInhaled 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 with Pseudomonas aeruginosa in patients with COPD.MethodsWe 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 acquiring P. aeruginosa. Propensity score matched models were used as sensitivity analyses.ResultsA total of 21 408 patients were included in the study, of which 763 (3.6%) acquired P. aeruginosa during follow-up. ICS use was associated with a dose-dependent risk of P. 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).ConclusionUse of ICS in patients with COPD followed in Danish outpatient clinics was associated with a substantially increased and dose-dependent risk of acquiring P. 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.