Clinical, Radiographic, and Physiological Correlates of Post-COVID-19 Dyspnea in Military Health System Beneficiaries: Results From the Chronic Impairment With Pulmonary Symptoms (ChIPS) Sub-study

BACKGROUND: Dyspnea has been described in up to 10-30% of patients post-SARS-CoV-2 infection. The underlying pathology for these persistent symptoms remains poorly understood. This study aimed to characterize changes in cardiopulmonary anatomical structure and physiology that may explain ongoing dyspnea after COVID-19.

METHODS: Participants had a history of symptomatic COVID-19, were between 18 and 65 years of age, and without significant pre-existing cardiopulmonary disease. Each participant underwent prospective chest high resolution computed tomography (HRCT), transthoracic echocardiography (TTE), electrocardiogram (ECG), pulmonary function testing (PFT) with lung volumes and diffusing capacity for carbon monoxide (DLCO), impulse oscillometry (IOS), and a six-minute walk test (6MWT) with Borg dyspnea scoring.

RESULTS: Among 115 enrolled participants, 39 had persistent dyspnea. The mean forced expiratory volume at 1 s/forced vital capacity (FEV 1/FVC) ratio was higher in those with persistent dyspnea, but within normal ranges for both groups. There were no other statistically significant differences in FEV 1, FVC, and DLCO between the groups. Those with ongoing dyspnea had a decreased walk distance (difference of 50.4 m, P = .01). Resting and post-6MWT Borg scores were 0.9 and 1.3 higher in those with persistent dyspnea, respectively ( P-values <.001). There were no significant differences in IOS, HRCT, TTE, or ECG findings between groups.

CONCLUSIONS: This study demonstrated a difference in 6MWT distance and Borg scores between those with and without persistent dyspnea. There were no clear PFT, cardiac test, or HRCT findings that explained these persistent symptoms. Overall, this study demonstrates both subjective and objective differences between those with ongoing dyspnea following COVID-19 that are not explained by standard investigations typically ordered in clinical care for chronic dyspnea. These findings underscore the importance of further research into the etiology of post-COVID-19 dyspnea, including other investigations which may detect more subtle alterations in pulmonary physiology.