C-reactive protein-to-lymphocyte ratio is a reliable marker in patients with COVID-19 infection: the CLEAR COVID study.

Abstract

COVID-19 infection is characterized with elevation of inflammatory markers in bloodstream. A novel inflammatory marker, C-reactive protein (CRP)-to-lymphocyte ratio (CLR), is suggested to be associated with inflammation. We aimed to compare the CLR values of the deceased COVID-19 patients to the CLR of survived subjects. The patients with COVID-19 whom presented to outpatient or inpatient clinics of AbantIzzet Baysal University Hospital were enrolled to the present retrospective study. Subjects were grouped as either deceased or survived. CLR values of the groups were compared. Study cohort was consisted of 568 subjects in deceased and 4753 patients in survived group. Median CLR of the deceased and survived groups were 90 (0.2-1679)% and 11 (0.2-1062)%, respectively (p < 0.001). The sensitivity (75%) and specificity (70%) of CLR (> 23.4% level) in detecting mortality were higher than those of CRP and ferritin (AUC 0.80, p < 0.001, 95% CI 0.78-0.82). We suggest that elevated CLR levels in COVID-19 patients on admission should alert physicians for poor outcome.