Neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio associated with 28-day all-cause mortality in septic patients with coronary artery disease: a retrospective analysis of MIMIC-IV database

Abstract Background High Neutrophil-to-Lymphocyte Ratio (NLR), Monocyte-to-Lymphocyte Ratio (MLR), Platelet-to-Lymphocyte Ratio (PLR) were associated with worse prognosis of patients with sepsis. In-hospital mortality has been reported to be higher in patients with coronary artery disease (CAD) and sepsis than those with sepsis alone. However, the relationship between NLR, MLR, PLR and mortality in septic patients with coronary artery disease (CAD) remains unclear. The study aimed to explore the association between NLR, MLR, PLR and 28-day all-cause mortality in septic patients with CAD. Methods We performed an observational cohort study of septic patients with CAD from the Medical Information Mart for Intensive Care (MIMIC)-IV database between 2008 and 2019. The patients were categorized by three group (Q1: low levels, Q2: medium levels, Q3: high levels) based on tertiles of NLR, MLR, and PLR. The associations between NLR, MLR, PLR and 28-day all-cause mortality were examined using the Cox proportional hazards model. Subsequently, we applied receiver operating characteristic (ROC) analysis for predicting 28-day mortality in septic patients with CAD by combining NLR, MLR and PLR with the modified sequential organ failure assessment (mSOFA) scores. Results Overall 1,175 septic patients with CAD were included in the study. Observed all-cause mortality rates in 28 days were 27.1%. Multivariate Cox proportional hazards regression analysis results showed that 28-day all-cause mortality of septic patients with CAD was significantly related to rising NLR levels (adjusted hazard ratio aHR: 1.02; 95% confidence interval CI: 1.01–1.02; P < 0.001), MLR levels (aHR: 1.29; 95%CI: 1.18–1.41; P < 0.001), and PLR levels (aHR: 1.0007; 95%CI: 1.0004–1.0011; P < 0.001). Meanwhile, the higher levels (Q3) group of NLR, MLR, and PLR also had a higher risk of 28-day all-cause mortality than the lower (Q1) group. The area under the ROC curve of NLR, MLR, PLR, and mSOFA score were 0.630 (95%CI 0.595–0.665), 0.611 (95%CI 0.576–0.646), 0.601 (95%CI 0.567–0.636) and 0.718 (95%CI 0.689–0.748), respectively. Combining NLR, MLR, and PLR with mSOFA scores may improve ability of predicting 28-day mortality (AUC: 0.737, 95%CI 0.709–0.766). Conclusion Higher levels of NLR, MLR and PLR were associated with 28-day all-cause mortality in septic patients with CAD. Further investigation will be needed to improve understanding of the pathophysiology of this relationship.