Long-term changes in spirometry and diffusing capacity in Mexican Hispanics with previous severe COVID-19

Background: This longitudinal study (April 2020 - January 2023) investigated lung function (spirometry, pulmonary diffusing capacity) in Mexican Hispanics who experienced severe COVID-19. It focused on how recovery time affects lung function improvements, hypothesizing that patients with a longer recovery between diagnosis and pulmonary testing would show better lung function than those tested earlier.

Methods: At a COVID-19 follow-up clinic in Yucatan, Mexico, lung function and symptoms were assessed in patients recovered from severe COVID-19. We used z-scores and Wilcoxon signed rank tests to analyze lung function changes over time. Lung function was measured twice in 82 patients: at a median of 94 and 362 days after COVID-19 diagnosis. High-resolution computed tomography (HRCT) was conducted in 44 of these 82 subjects, with a median time of 38 days between CT scanning and a pulmonary function test. Z-scores were determined using reference equations for spirometry (doi: 10.1164/rccm.202205-0963OC) and DLCO [Gochicoa-Rangel L. G. et al., (2024). Reference equations for DLNO & DLCO in Mexican Hispanics: Influence of altitude and race. BMJ Open Respir Res, in press as of September 2024].

Seven pulmonary ailments were assessed, identified based on the 2022 ERS/ATS interpretation strategies (doi: 10.1183/13993003.01499-2021): (A) Restrictive spirometry pattern (FEV1/FVC > LLN, FVC < LLN); (B) Airflow obstruction (FEV1/FVC < LLN, FVC > LLN); (C) Mixed disorder (FEV1/FVC < LLN, FVC < LLN); (D) Loss of alveolar-capillary structure with loss of lung volume (DLCO < LLN, VA < LLN, KCO < ULN); (E) Localized loss of lung volume or incomplete lung expansion (DLCO < LLN, VA < LLN, KCO > ULN); (F) Pulmonary vascular abnormality (DLCO < LLN, VA normal); and (G) Alveolar hemorrhage, polycythemia, increased blood flow (left to right shunt, or post-exercise).

Results: Initially, 61% of patients exhibited at least one of seven pulmonary function abnormalities (LLN = –1.645), which decreased to 22% by 390 days post-recovery. Considering day-to-day variability, 68% of patients showed improvement by the final visit, while 30% had unchanged lung function from the initial assessment. Computed tomography (CT) scans revealed ground-glass opacities in 33% of patients. One year after infection, DLCO z-scores accounted for 29% of the variation in HRCT fibrosis scores. No significant correlation was found between recovery length and lung function improvement based on z-scores.

Conclusion: Twenty-Two percent of patients who recovered from severe COVID-19 continued to show at least one lung function abnormality one year after recovery, indicating a prolonged impact of COVID-19 on lung health.

The data is in SPSS (.sav) format. Once the file is open you will find the labels for each parameter under the "VARIABLE VIEW" tab.