Incidence of community-acquired pneumonia hospitalisation in persons with bronchiectasis during the COVID-19 lockdown in Denmark: a retrospective cohort study

Background: Persons with bronchiectasis have a high risk of community-acquired pneumonia. Social distancing measures, implemented to prevent the spreading of SARS-CoV-2, could potentially reduce the incidence of other infectious diseases.

Research question: Was the COVID-19 lockdown period, along with accompanying social distancing measures, associated with reduced hospital admissions for community-acquired pneumonia and decreased overall mortality rates among individuals with bronchiectasis?

Methods: Social distancing measures were introduced in Denmark by 12 March 2020 and were preserved until 20 May 2020 (social distancing period), after which the measures were gradually dismissed. The study included all adults (≥18 years) with bronchiectasis residing in Denmark. Confirmed cases of SARS-CoV-2 infection were excluded. We retrospectively investigated the incidence of community-acquired pneumonia hospital admission, death of all causes and respiratory antibiotic treatment in the 10-week social distancing period in 2020, compared with the same dates in 2019. 9344 persons were included in the study.

Results: In the social distancing period, the incidence rate of pneumonia-hospitalisation per 10 000 person-weeks was 9.2 compared with 13.8 in the reference period. This reduction corresponds to an incidence rate ratio (IRR) of 0.67 (95% CI 0.51 to 0.88, p<0.01). Mortality was unchanged (IRR 0.90, 95% CI 0.61 to 1.32, p=0.58). Fewer persons received respiratory antibiotics (IRR 0.85, 95% CI 0.78 to 0.94, p<0.001).

Conclusion: The social distancing period was associated with a lower incidence of community-acquired pneumonia hospitalisations and respiratory antibiotic treatments in persons with bronchiectasis while all-cause mortality remained unchanged.