Lung function decline in relation to COVID-19 in the general population: a matched cohort study with pre-pandemic assessment of lung function

Objective To quantify the potential decline in dynamic lung volumes following coronavirus disease 2019 (COVID-19) in the general population. Methods A prospective matched cohort study of adult Copenhagen General Population Study (CGPS) participants with a pre-pandemic spirometry available. CGPS individuals with a positive SARS-CoV-2 polymerase chain reaction (PCR) test performed a repeat spirometry, a questionnaire regarding respiratory symptoms and a diffusing capacity test for carbon monoxide. A matched uninfected CGPS control sample was used, and simple regression and linear mixed effect models were computed to study lung function decline. Results A total of 606 were included. 92/107 (85.9%) of individuals with a positive SARS-CoV-2 PCR test experienced COVID-19 symptoms and 12 (11.2%) were hospitalized. Spirometry was performed at a median (interquartile range) of 5.6 (3.9-12.8) months after positive SARS-CoV-2 PCR test. COVID-19 was associated with an adjusted 7.3 mL (95%CI: 0.3-14.3) and 22.6 mL (95%CI: 13.1-32.0) steeper decline in annual FEV1 and FVC or a total of 113.8 and 301.3 ml lower FEV1 and FVC from baseline to follow up. Results were robust in analyses restricted to individuals not requiring hospitalization. Conclusion COVID-19 related decline of dynamic lung volumes in the general population not requiring hospitalization were small but measurable.