Prognostic value of neutrophil- lymphocyte count ratio (NLCR) among adult ICU patients in comparison to APACHE II score and conventional inflammatory markers: a multi center retrospective cohort study

BACKGROUND: Neutrophil-lymphocyte count ratio (NLCR) has been reported as better indicator of bacteremia than procalcitonin (PCT), and more precise predictor of mortality than C-reactive protein (CRP) under various medical conditions. However, large controversy remains upon this topic. To address the discrepancy, our group has compared the efficiency of NLCR with conventional inflammatory markers in predicting the prognosis of critical illness. METHODS: We performed a multi-center retrospective cohort study involving 536 ICU patients with outcomes of survival, 28- and 7-day mortality. NLCR was compared with conventional inflammatory markers such as PCT, CRP, serum lactate (LAC), white blood cell, neutrophil and severity score APACHE II (Acute Physiology and Chronic Health Evaluation II) to evaluate the potential outcomes of critical illness. Then, receiver operating characteristics (ROC) curves were constructed to assess and compare each marker’s sensitivity and specificity respectively. RESULTS: NLCR values were not different between survival and mortality groups. Meanwhile, remarkable differences were observed upon APACHE II score, CRP, PCT and LAC levels between survival and death groups. ROC analysis revealed that NLCR was not competent to predict prognosis of critical illness. The AUROCs of conventional markers such as CRP, PCT, LAC and APACHE II score were more effective in predicting 28- and 7-day mortality. CONCLUSIONS: NLCR is less reliable than conventional markers CRP, PCT, LAC and APACHE II score in assessing severity and in predicting outcomes of critical illness. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12873-021-00418-2.