In patients who have been hospitalized for a COVID-19 infection, differences in lung function have been reported according to race/ethnicity group, with non-Hispanic Black individuals having statistically significant lower diffusion capacity of carbon dioxide (DLCO) % predicted compared with non-Hispanic White and Hispanic patients. These were among findings of a single-center, prospective cohort study by researchers at University of Virginia Medical Center (UVAMC), reported in Respiratory Medicine.
Recognizing that ethnic minorities have higher rates of infection, hospitalization, and death from COVID-19 compared with White Americans, researchers at UVAMC sought to explore whether race/ethnicity is an independent predictor of lung dysfunction following COVID-19-associated hospitalization.
Adult patients who had been hospitalized at UVAMC with COVID-19 infection between March 2020 and January 2021were asked to complete a questionnaire within 30 days of discharge. Those who experienced persistent respiratory symptoms were invited to undergo complete spirometry, lung volumes, and DLCO measurements. A total of 128 patients completed pulmonary function testing at 6 months (average time to follow-up, 186 days).
Results of the study showed impairments in lung function that were evident in spirometry, lung volumes, and DLCO at 6 months. The most predominant impairments were observed in forced vital capacity (FVC; 24.4%), forced expiratory volume in 1 second (FEV1; 20.5%), total lung capacity (TLC; 23.3%), and DLCO (20.8%).
When these indicators were compared among race/ethnicity groups, 3 lung function parameters demonstrated statistically significant differences: (1) FEV1/FVC ratio: P =.021; (2) residual volume (RV)/TLC ratio: P =.006; and (3) DLCO % predicted: P =.002. In fact, the average difference between Hispanic and non-Hispanic Blacks in terms of DLCO % predicted was 13.09 (P =.01), whereas the average difference between non-Hispanic Whites and non-Hispanic Blacks was 9.46 (P =.04).
Differences persisted when controlling for such variables as age, body mass index, history of chronic lung disease, admission to intensive care unit, smoking status, socioieconomic status, and corticosteroid treatments.
Several key limitations of the current study should be noted. The presence of a strong selection bias was observed, with the investigators limiting their efforts to those with persistent symptoms, rather than attempting to collect follow-up data on all patients, due to resource limitations within the pulmonary function laboratory. Further, a substantial percentage of participants had a previous diagnosis of either asthma or chronic obstructive pulmonary disease. Additionally, no radiographic data were included in the present study.
The researchers concluded that “Multivariable linear regression demonstrated that race/ethnicity had a statistically significant association with DLCO % predicted, with [non-Hispanic] Black patients having lower DLCO % predicted compared to Hispanic and [non-Hispanic] White patients even when corrected for important inter-groups differences. Whether this association represents some hidden confounder or is directly related to genetic variance is unknown.”
Konkol SB, Ramani C, Martin DN, et al. Differences in lung function between major race/ethnicity groups following hospitalization with COVID-19. Respir Med. Published online August 7, 2022. doi:10.1016/j.rmed.2022.106939