Histopathological findings in Lungs of COVID-19 infected subjects. A systematic review and meta-analysis

Abstract

Introduction. COVID-19 is a new disease that required prompt results from research. One approach to understanding its pathophysiology is to know the histopathological damage generated in the lungs of those affected. Objective. To provide a rigorous summary of the available evidence on pulmonary histopathological findings in patients with COVID-19. Methodology. A systematic review with a meta-analysis of proportions was developed. Primary studies of any design that had primary data on histopathologic findings of lungs in COVID-19 patients were included. Reviews and guidelines were excluded. Data sources were the Living OVerview of Evidence centralized repository, PubMed/Medline, LitCovid, the World Health Organization COVID-19 database, and medRxiv until April 3, 2021. A risk of bias assessment was performed using the Joanna Briggs Institute tools for case series and case reports. Each histopathologic pulmonary finding was extracted. The frequencies found were calculated, and the data for the most frequent findings were summarized in meta-analyses using the Der Simmonian-Liard random-effects method. Heterogeneity was measured. Results. Inclusion criteria were met by 69 articles totaling 594 subjects. Thirty-five articles were at low risk of bias. Meta-analysis of proportions showed diffuse alveolar damage in 0.62 (95 % CI 0.51-0.72), I2 59 % (p < 0.01), in its early phase (85.14 %). Conclusion. Early diffuse alveolar damage was the most frequent histopathological finding in lung specimens from patients with COVID-19.