Comparative Prognostic Accuracy of the Neutrophil-to-Lymphocyte Ratio and the Platelet-to-Lymphocyte Ratio for Predicting Mortality in Sepsis Patients in the Intensive Care Unit: Protocol for a Systematic Review and Meta-Analysis

Abstract

Introduction Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Rapid, affordable prognostic markers are needed in intensive care units (ICUs), where conventional clinical scores require multiple clinical and laboratory parameters. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) can be calculated from routine complete blood counts and have each been associated with mortality in sepsis. However, their relative prognostic accuracy in ICU patients has not been systematically compared. Materials and Methods This protocol describes a systematic review and meta-analysis of prospective and retrospective observational studies in adults with sepsis treated in ICUs. PubMed/MEDLINE, Scopus, and ProQuest will be searched for English-language studies published from 2006 to 2026. Two independent reviewers will screen studies, extract data, and assess risk of bias using the Newcastle–Ottawa Scale. The primary outcomes are ICU and/or 28-day mortality. Reported area under the curve (AUC), sensitivity, and specificity will be compared for NLR and PLR. Where studies are sufficiently comparable, pooled AUC and diagnostic-performance estimates will be calculated using appropriate random-effects models; otherwise, findings will be synthesized narratively. Expected Contribution The review will determine and compare the prognostic performance of NLR and PLR for mortality prediction in ICU patients with sepsis. The findings are intended to provide a more comprehensive evidence base for selecting an accessible prognostic indicator for mortality-risk assessment in this population. The study protocol has been registered in the PROSPERO database (CRD420261455772).