a b s t r a c tObjectives: The role of Pseudomonas aeruginosa in the long-term prognosis of chronic obstructive pulmonary disease (COPD) is unknown. The purpose of this study was to determine whether P. aeruginosa is associated with increased risk of exacerbations or death in patients with COPD. Methods: This is a multiregional epidemiological study based on complete data on COPD outpatients between 1 January 2010 and 31 October 2017 and corresponding microbiology and national register data. Time-dependent Cox proportional hazards models and propensity matching was used to estimate hospitalization-demanding exacerbations and death after 2 years, separately and in combination. Results: A total of 22 053 COPD outpatients were followed for a median of 1082 days (interquartilerange: 427e1862). P. aeruginosa was present in 905 (4.1%) patients. During 730 days of follow-up, P. aeruginosa strongly and independently predicted an increased risk of hospitalization for exacerbation or all-cause death (HR 2.8, 95%CI 2.2e3.6; p <0.0001) and all-cause death (HR 2.7, 95%CI 2.3e3.4; p <0.0001) in analyses adjusted for known and suspected confounders. The signal remained unchanged in unadjusted analyses as well as propensity-matched subgroup analyses. Among patients 'ever colonized' with P. aeruginosa, the incidence of hospital-demanding exacerbations doubled after the time of the first colonization. Conclusions: COPD patients in whom P. aeruginosa can be cultured from the airways had a markedly increased risk of exacerbations and death. It is still not clear whether this risk can be reduced by offering patients targeted antipseudomonal antibiotics. A randomized trial is currently recruiting patients to clarify this (ClinicalTrials.gov: NCT03262142).

The aim of the present study was to describe the prevalence and severity of asthma in young Danish adults over three decades.Males and females aged 20-35 yrs were sampled from the population of Copenhagen for the three surveys (1976-1978, 1991-1993 and 2001-2004). A total of 3,285 (46% male) subjects answered a questionnaire, and had their height, weight, forced expiratory volume in 1 s (FEV1) and forced vital capacity measured.The prevalence of self-reported asthma was 1.5, 4.7 and 6.9%, respectively, in the three surveys (p,0.001). An increasing prevalence of asthma was observed in both males and females, although it was highest among females. The difference in FEV1 between asthmatic and nonasthmatic subjects gradually increased, being 2.3 (p50.56) and 14.2% of the predicted value (p,0.001), respectively, in 1976-1978 and 2001-2004. From the 1991-1994 survey, increasing body mass index, especially .30 kg?m -2 , was associated with a lower percentage predicted FEV1 (pf0.005), and further analyses suggested an additive effect of asthma and obesity on FEV1. The proportion of smokers declined from 60 to 38% (p,0.001).The prevalence and severity of asthma have continued to increase over the last three decades among young Danish adults, and the observed increase in severity seems, at least partly, to be related to the increase in prevalence of obesity.

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.