Pulmonary Symptoms After Mild COVID: A Retrospective Observational Study

Background: Patients with a mild or asymptomatic acute phase of COVID-19 have reported persisting or emerging symptoms weeks or months after the initial infection. The purpose of this study was to review pulmonary function testing of patients with either a diagnosis or symptoms of long COVID following a mild acute phase. The aim was to identify what, if any, relationships existed among symptoms of pulmonary sequelae and measurements of pulmonary function. Methods: A retrospective review of patients at a single center who received PFT and 6MWT for long COVID symptoms following a mild acute phase of COVID-19 was completed. Adult subjects were identified through electronic medical records if they received services between March 1, 2020, and September 2, 2023. The records of 19 patients were included in this review. Pearson’s correlation coefficient was used to analyze the relationship between dyspnea symptoms and overall pulmonary function, and DLCO and fatigue scores. Finally, the relationship between dyspnea and 6MWD was analyzed using the Phi correlation coefficient. Results: Weak correlations were identified between the reported dyspnea and pulmonary function (r(17) = -0.09, P = .72, DLCO (r(17) = -0.14, P = .58), and 6MWD (r(1) = 0.05, P = .37). There was a strong positive correlation between dyspnea and fatigue (r(17) = 0.75, P < .001). The sample size limits the analysis, but the data substantiates the need for additional research. Conclusions: The degree of pulmonary impairment did not appear to correlate with the degree of symptoms reported by patients. Additionally, pulmonary function impairment did not appear to be the primary cause of dyspnea and fatigue in patients following a mild acute phase of COVID-19.