The Predictive Role of C-Reactive Protein, Leukocyte Cell Count, and Soluble Urokinase Plasminogen Activator Receptor for Pulmonary Sequelae in Hospitalized COVID-19 Survivors: A Prospective Single-Center Cohort Study

Abstract

Background Pulmonary function impairment has profound effects on patient quality of life, working ability, and healthcare utilization. Among individuals suffering from Coronavirus disease (COVID-19), a range of severity in respiratory symptoms is observed. We therefore investigated whether levels of biomarkers associated with respiratory function and inflammation in patients with COVID-19 upon admittance to the Emergency Department (ED) are predictive of long-term pulmonary function impairment among COVID-19 survivors. Methods In this prospective single-center study, patients were recruited upon attending their follow-up visits 4–5 months after experiencing severe COVID-19 infection. These patients underwent pulmonary function tests at the respiratory outpatient clinic as part of clinical standard procedure. Diffusing capacity of the lungs for carbon monoxide (DLCO) was chosen as the primary clinical measure and a diffusion deficit (DLCO <80% predicted) was the primary endpoint. DLCO and total lung capacity (TLC) were measured using the single-breath method. Forced Expired Volume in the first second (FEV1) and Forced Vital Capacity (FVC) were also measured. Baseline biomarkers, C-Reactive Protein (CRP), leukocyte cell counts, and soluble urokinase Plasminogen Activator Receptor (suPAR) were measured and the correlation with post discharge DLCO values were assessed. Results: A total of 110 patients with COVID-19 were enrolled in the study. Sixty-four (58.2%) were females, median age was 61.5 years and average BMI was 27.2. Of the participants, 53.7%, 43.5%, and 2.8% were never-smokers, former smokers, and current smokers, respectively; median tobacco exposure for current and former smokers was 18 pack-years.