The role of 6-minute walk test and pulmonary function testing in patients with post COVID-19 condition: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE: Post-COVID-19 condition (PCC) is a complication of acute COVID-19 infection, which often presents with respiratory symptoms. This review aimed to assess the prevalence of abnormal pulmonary function test (PFTs) and 6-minute walk test (6MWT) with oximetry findings, and their respective prevalence and magnitude of abnormalities in patients with PCC, compared to patients without PCC. METHODS: We searched three databases. Two reviewers independently screened articles using LASER Al and extracted relevant data using a piloted Excel sheet. We performed meta-analysis using OpenMeta and RevManWeb and a subgroup analysis based on patients' settings during acute COVID-19. We assessed the risk of bias using the Hoy et al. tool and the certainty using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. RESULTS: We included 30 studies that reported on the prevalence of abnormal PFTs and/or 6MWT in patients with PCC. Outcomes within PFTs and 6MWT showed that patients with PCC have a higher probability of having abnormal tests, with those hospitalized during their acute COVID-19 infection showing a higher probability of having abnormal tests. The overall certainty of the evidence was very low due to the high risk of bias, indirectness, and imprecision. CONCLUSION: This review provides insight into the utilization of PFTs and 6MWT and the frequency of test abnormalities in patients with PCC. Despite existing evidence, there is a need for future studies to assess the diagnostic test accuracy of these tests in PCC.