Serum-calprotectin for identification of severe COVID-19 in hospitalized patients

ABSTRACT

Introduction: The disease severity of COVID-19 varies from mild upper respiratory tract infection to life-threatening lower respiratory tract infection. Biomarkers can support severity assessment. We aimed to compare scalprotectin with routine biomarkers to study if s-calprotectin could identify patients with risk for severe COVID-19. We also aimed to study if ongoing corticosteroid therapy would alter levels of s-calprotectin. Method(s) We collected serum samples within 8 days from admission from 162 adult patients hospitalized for COVID-19 from April to October 2020. The serum tubes were centrifuged within 2 h and serum was aspirated and frozen in aliquots at -80 degreeC. scalprotectin was measured according to the routine method at Karolinska University Laboratory. Study endpoint was severe COVID-19 any time during the hospital stay. Severe COVID-19 was defined as treatment with either low-flow oxygen >= 10 l/min, high-flow nasal oxygen, non-invasive ventilation, or invasive mechanical ventilation. For patients hospitalized before the results of the RECOVERY Dexamethasone study were presented, a propensity score matched sub-study was performed, comparing patients treated and not treated with corticosteroids prior to study sample. Result(s) Median s-calprotectin was, 2.7 ml/L (IQR, 1.6-4.2) for nonsevere COVID-19 cases (n = 59) and 5.0 ml/l (IQR, 3.5-9.1) for severe COVID-19 (n = 103) (p < 0.001). ROC-curve analysis compering s-calprotectin, C-reactive protein (CRP), neutrophils, 1/lymphocytes, and D-dimer, showed the highest AUC for s-calprotectin, 0.775 (Fig. 1). In the sub-study of with corticosteroid treated (n = 35) and non-treated patients (n = 26), the median s-calprotectin was 4.0 (IQR, 2.5-5.6) and 3.8 (IQR, 2.7-3.8), respectively (p = 1.0). Conclusion(s) The study showed a good performance of s-calprotectin for identification of severe COVID-19, in agreement with previous studies. It also indicated that s-calprotectin results are not affected by ongoing corticosteroid treatment.