Post-Discharge Spirometry Evaluation in Patients Recovering from Moderate-to-Critical COVID-19: A Prospective Cohort Study

To determine the prevalence and types of spirometry abnormalities among post-COVID-19 patients in Malaysia, with secondary objective focusing on associated factors. Conducted at the COVID-19 Research Clinic, Faculty of Medicine, University Technology MARA, from March 2021 to December 2022, this study included patients three months post-discharge from hospitals following moderate-to-critical COVID-19. Of 408 patients studied, abnormal spirometry was found in 46.8%, with 28.4% exhibiting a restrictive pattern, 17.4% showing preserved ratio impaired spirometry (PRISm), and 1.0% displaying an obstructive pattern. Factors independently associated with abnormal spirometry included older age (OR: 1.0, 95% CI: 1.01–1.04, p = 0.003), underlying cardiovascular disease (OR: 3.5, 95% CI: 1.19–10.47, p = 0.023), history of acute respiratory distress syndrome (p < 0.001), shorter discharge-to-follow-up interval (OR: 0.9, 95% CI: 1.00–1.02, p = 0.035), oxygen desaturation during 6-minute walk test (OR: 1.9, 95% CI: 1.20–3.06, p = 0.007), and presence of consolidation (OR: 8.1, 95% CI: 1.75–37.42, p = 0.008) or ground-glass opacity (OR: 2.6, 95% CI: 1.52–4.30, p < 0.001) on chest X-ray. This study highlights patients recovering from moderate-to-critical COVID-19 often exhibit abnormal spirometry, notably a restrictive pattern and PRISm. Routine spirometry screening for high-risk patients is recommended.