Evaluation of simple laboratory parameters in SARS-CoV-2 infection: the role of ratios

Abstract

Background: The real predictive prognostic capacity of cellular indices (or ratios) is unclear in SARS-CoV-2 infection. This study aimed to assess the prognostic role of previously well-known laboratory indices and new ones in hospitalized COVID-19 patients.

Methods: A retrospective observational study from March to May 2022 evaluated laboratory indices on admission (neutrophil to lymphocyte-, derived neutrophil to lymphocyte-, platelet to lymphocyte-, CRP to lymphocyte-, CRP to albumin-, fibrinogen to lymphocyte-, d-dimer to lymphocyte-, ferritin to lymphocyte-, LDH to lymphocyte-, and IL-6 to lymphocyte ratios), in patients hospitalized due to SARS-CoV2 infection to determine the association with mortality, admission to an intensive care unit (ICU), need for non-invasive mechanical ventilation (NIMV), orotracheal intubation (OTI), or combined event at 30 days follow-up.

Results: A total of 1113 COVID-19 patients were evaluated with a mean age of 64.1 ± 15.9 years (58.49% male), 166 (14.91%) patients died, 58 (5.21%) required ICU admission, 73 (6.56%) needed NIMV, 46 (4.23%) needed OTI, and 247 (22.19%) presented the combined event. All the ratios evaluated in this study showed statistical significance in the univariate analysis for mortality and combined event; however, only d-dimer to lymphocyte ratio >0.6 presented an independent association in the multivariate analysis for 30-day mortality (adjusted OR 2.32; p = .047) and 30-day combined event (adjusted OR 2.62; p = .014).

Conclusions: Laboratory indices might be a potential biomarker for better prognosis stratification in hospitalized COVID-19 patients. d-Dimer to lymphocyte ratio presents an independent association for 30-day mortality and 30-day adverse outcomes in hospitalized COVID-19 patients.