Patterns and Trajectories of Pulmonary Function in Coronavirus Disease 2019 Survivors: An Exploratory Study Conducted in Central India

Background: The ongoing pandemic of coronavirus disease 2019 (COVID-19) has negatively impacted respiratory health worldwide. The severity of the disease varies considerably, and patients may present with bronchitis, pneumonia, and acute respiratory distress syndrome. This study aims to quantify the parameters of the pulmonary function test (PFT) with regard to the severity of COVID-19 and understand the pattern of PFT in reference to the status of selected morbidities and body mass index. Materials and methods: This is a hospital-based, comparative, cross-sectional study. A total of 255 COVID-19 survivors underwent clinical assessment, a PFT, and a 6-minute walk test. Participants were divided into mild, moderate, and severe disease groups. The parameters were compared between these groups. The PFT and 6-minute walk tests were conducted using an NDD Digital computerized spirometer (NDD Meditechnik AG., Switzerland) and a fingertip pulse oximeter (Hasely Inc., India), respectively. Results: All PFT parameters showed significant differential distribution among the severity groups (p<0.001) except for forced expiratory volume in 1 s/ forced vital capacity (FEV(1)/FVC) and forced expiratory flow (FEF) during 25%-75% expiration and peak expiratory flow (PEF). Among severe category participants forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), and FEV(1)/FVC, were significantly reduced as compared to mild and moderate. Severity was significantly affected by age >50 years. Severe category participants were seen in 31% of normal, 58% of pre-obese, and 53% of obese participants; however, this difference was insignificant. A significant reduction in SPO2 on the 6-minute walk test was observed in severely sick participants. Conclusions: COVID-19 is associated with a mixed pattern of spirometry. Poor prognosis is associated with older age, obesity, and multimorbidity.