One-Fourth of COVID-19 Patients Have an Impaired Pulmonary Function after 12 Months of Illness Onset – THE LANCET
24 Feb 2023
Background: This longitudinal study evaluates the extent of impaired pulmonary function over time after SARS-CoV-2 infection across the full spectrum of COVID-19 severity.
Methods: Pulmonary function was measured by diffusing capacity for carbon monoxide (DLCO) at one, six, and twelve months after illness onset. Additionally, data on sociodemographics, clinical characteristics, symptoms, and health-related quality of life (HRQL) were collected. Pulmonary function and determinants were modelled over time using mixed-effect linear regression. Determinants of pulmonary impairment at 12 months since illness onset were identified using logistic regression.
Findings: Between May 2020 and December 2021, 301 of 349 participants underwent at least one pulmonary function test. After one year of follow-up, 25% of the participants had an impaired pulmonary function which translates in 11%, 22%, and 48% of the participants with mild, moderate and severe/critical COVID-19. Improvement in DLCO among the participants continued over the period across one, six and twelve months. Having more than three comorbidities (p<0·001) and initial severe/critical illness (p<0·001) were associated with slower improvement of pulmonary function over time, adjusted for age and sex. HRQL improved over time and was not different to those without impaired pulmonary function.
Interpretation: The prevalence of impaired pulmonary function after twelve months of follow-up, was still significant among those with initially moderate or severe/critical COVID-19. However, those who continued to have impaired pulmonary function after one year did not have impaired HRQL.