Neutrophil-to-lymphocyte ratio and D-dimer are biomarkers of death risk in severe COVID-19: A retrospective observational study

Background and aims: Over 4 million deaths from coronavirus disease (COVID)-19 have been reported in the world. Several biomarkers have been identified that predict disease severity, but there is still a need to identify biomarkers for death risk in severe COVID-19. We aim to define amongst the biomarkers already identified those which are mostly associated with increased death rate in patients with severe COVID-19.

Methods: In this retrospective study conducted in three public hospitals linked to the Medical School of Ribeirão Preto, Brazil, patients with severe COVID-19 were evaluated regarding biomarkers (neutrophil-to-lymphocyte ratio-NLR, D-dimer, fibrinogen) of death risk, obtained before administration of corticosteroids.

Results: Thirty-nine (32.8%) of the 119 patients included (104 [87.4%] on mechanical ventilation) died during hospitalization. Non-survivor group had higher median (range) NLR (12.63 [2.6-115] vs 7.43 [0.43-31.8]; P = .001), D-dimer (2.17 [0.27-20.00] vs 1.57 [0.28-20.00]; P = .03), but lower fibrinogen (631 [353-1078] vs 705 [407-1200]; P = .02). The group with NLR ≥ 10 and D-dimer ≥ 2 μg/mL had a higher death risk than the group with NLR < 10 and D-dimer < 2 μg/mL (OR: 5.39; CI 95%: 1.5-19.42; P = .01).

Conclusion: High NLR and D-dimer, especially when combined, are predictors of death risk for patients with severe COVID-19 and should be incorporated into their evaluation.