Association of the neutrophil–lymphocyte ratio to patient outcomes after trauma: A systematic review

Abstract

Introduction

Early identification of trauma injury severity is important for prognostication. The neutrophil–lymphocyte ratio (NLR) has been proposed as a marker of systemic inflammation in major trauma patients that is associated with in-hospital mortality. The aim of this systematic review is to compile all the best evidence available to determine the prognostic capabilities of the NLR in trauma and to assess the NLR as a predictor of mortality in adult major trauma patients. Additionally, comparing NLR and hospital length of stay (LOS), ICU LOS, mechanical ventilation and transfusion requirements.

Methods

We conducted a search of online information sources to identify manuscripts observing the NLR in adult major trauma patients. Outcomes of interest include mortality as defined by the author, hospital LOS, ICU LOS, mechanical ventilation and transfusion requirements. Quality was assessed using the Newcastle–Ottawa Scale. We aimed to conduct a meta-analysis if there were sufficient manuscripts included.

Results

Eight studies fulfilled our inclusion criteria. Trials were of good methodological quality. Substantial heterogeneity present between the studies prevented a meta-analysis from being conducted. Overall, five studies demonstrated the NLR as a significantly predictive marker of mortality. NLR was observed to be significantly associated with increased ICU LOS and longer duration of mechanical ventilation. Mixed results were observed between NLR and hospital LOS and transfusion requirements.

Conclusions

A potential association between NLR and mortality, ICU LOS and duration of mechanical ventilation has been reported. However, clinical utility of this measure during trauma resuscitation remains unknown.