Prognostic role of simple inflammatory biomarkers in patients with severe COVID-19: an observational study

Abstract

Background/aim: Simple inflammatory biomarkers, such as neutrophil to lymphocyte ratio (NLR), could serve as prognosis indicators in patients with Coronavirus disease 2019 (COVID-19). The utility of on-admission inflammatory biomarkers in predicting outcomes was investigated in patients suffering from severe COVID-19 infection.

Methods: We performed a retrospective study to assess the role of white blood count (WBC), neutrophils (N), lymphocyte (L), platelets (PLTs), C-reactive protein (CRP), reverse transcription polymerase chain reaction (RT-PCR), NLR (N/L), PLR (P/L), dv (derived variation of)-NLR (N/WBC-L), LNR (L/N), dv (derived variation of)-LNR (L/WBC-N), and CLR (CRP/L), in predicting the need for high-flow nasal cannula (HFNC) use, admission to Intensive Care Unit (ICU), and death in adult patients with severe COVID-19 admitted to the Department of Respiratory Medicine from April to September 2021.

Results: One hundred and fifteen patients (60 % males) with a mean age of 57.7 ± 16.3 years were included. Thirty-seven patients (32.2 %) required escalation with HFNC, eight patients (7 %) were admitted to the ICU, and nine patients (7.8%) died. Based on univariate analysis, CRP [odds ratio (OR): 1.25, 95 % confidence interval (CI): 1.1-1.42), LNR (OR: 0.015, 95 % CI: 0.00-0.35), dv-NLR (OR: 5*10⁶, 95 % CI: 26.7-9*10⁹), CLR (OR: 7*10⁵⁸, 95 % CI: 3*10²⁵-2*10⁹²), length of hospitalization (LOH; OR: 1.44, 95 % CI: 1.22-1.63), dyspnea at presentation (OR: 2.83, 95 % CI: 1.23-6.52), and ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂) on admission (OR: 0.967, 95 % CI: 0.952-0.983) were independent predictors for oxygen requirements. However, the multivariate analysis showed that LNR (OR: 1.686e0^-4, 95 % CI: 6.441e00^-8-0.441), PaO₂/FiO₂ on admission (OR: 0.965, 95 % CI: 0.941-0.989), and LOH (OR: 1.717, 95 % CI: 1.274-2.314) were the most important predictor for HFNC use. Nasal congestion at presentation (OR: 11.5, 95 % CI: 1.61-82.8) was a unique and independent predictor for ICU admission. As far as death is concerned, the univariate analysis identified elevated CRP (OR: 1.11, 95 % CI: 1.0-1.24), low RT-PCR (OR: 0.829, 95 % CI: 0.688-0.999), high CLR (OR: 3.2*10³³, 95 % CI: 5.8-1.8*10⁶⁶), age (OR: 1.08, 95 % CI: 1.02-1.14), body mass index (BMI) over 30 (OR: 5.25, 95 % CI: 1.26-21.96), the chronic use of angiotensin-converting enzyme inhibitors (OR: 5.72, 95 % CI: 1.35-24.09), nitrates (OR: 14.85, 95 % CI: 1.81-121.8), diuretics (OR: 8.21, 95 % CI: 1.97-34.32), PaO₂/FiO₂ on admission (OR: 0.983, 95 % CI: 0.970-0.998), and nasal congestion at presentation (OR: 9.81, 95 % CI: 1.40-68.68) as independent predictors. However, the multivariate analysis pinpointed that obesity (BMI >30) (OR: 10.498, 95 % CI: 1.107-99.572) remained the most important predictor for death.

Conclusion: LNR and PaO₂/FiO₂ on admission could be used to timely identify patients requiring HFNC during hospitalization, while obesity (BMI >30) could be an independent predictor of death. Nasal congestion emerges as a unique predictor for ICU admission. HIPPOKRATIA 2022, 26 (2):70-77.

Keywords: Biomarkers; C-reactive protein; COVID-19; Coronavirus disease 2019; SARS-CoV-2; length of hospitalization; lymphocyte subsets; obesity; prognosis; severe acute respiratory syndrome coronavirus 2.

Figure 1. Graph presenting the multivariate model for the high-flow nasal cannula use prediction. AUC: area under the curve, HFNC: high-flow nasal cannula,CRP: C-reactive protein, LOH: length of hospitalization, LNR: lymphocytes/neutrophils, CRP: C-reactive protein, LNR: lymphocytes/neutrophils, dv-NLR: (derived variation of)-NLR(neutrophils/ lymphocytes), CLR: CRP/ lymphocytes, P/F ratio: PaO2 (arterial blood oxygen partial pressure)/FiO2 (fraction of inspired oxygen) ratio

Figure 2. Graph presenting the multivariate model for death prediction. AUC: area under the curve, ACE: angiotensin-converting enzyme, CRP: C-reactive protein, RT-PCR: reverse transcription polymerase chain reaction, CLR: CRP/ lymphocytes, P/F ratio: PaO2 (arterial blood oxygen partial pressure)/FiO2 (fraction of inspired oxygen) ratio