Correlation between the neutrophil-to-lymphocyte ratio and the 90-day all-cause mortality in patients with acute respiratory failure: a retrospective analysis based on the MIMIC-IV Database

Abstract

Introduction: This study aims to examine the impact of the neutrophil-to-lymphocyte ratio (NLR) on 90-day all-cause mortality in individuals suffering from acute respiratory failure (ARF). Methods: Retrospectively including ARF patients from the MIMIC IV database, we classified them into the survivor and non-survivor cohorts according to their 90-day all-cause mortality rate. Demographic information, comorbidity, laboratory parameters, and other indices were collected. Results: A total of 3941 patients aged 65.0 years were enrolled in this. Multivariate COX regression analysis identified age(HR = 1.034, 95%CI:1.025–1.042,P < 0.001), history of chronic obstructive pulmonary disease(HR = 1.406, 95%CI:1.051–1.879,P = 0.022), history of hypertension(HR = 1.287, 95%CI:1.021–1.622,P = 0.032), history of type 2 diabetes mellitus(HR = 1.389, 95%CI:1.073–1.798,P = 0.013),history of coronary heart disease(HR = 2.138, 95%CI:1.639–2.788,P < 0.001), respiratory rate(HR = 1.043, 95%CI:1.026–1.01,P < 0.001), platelets (HR = 0.998, 95%CI: 0.997–0.999,P = 0.001), hemoglobin(HR = 0.859, 95%CI:0.820–0.901,P < 0.001), serum sodium (HR = 0.959, 95%CI:=0.041) and NLR(Q4, in comparison to Q1, HR = 1.627, 95%CI:1.167–2.268,P = 0.004) as independent predictors of the 90-day all-cause mortality rate. The relationship between NLR and mortality was observed to be non-linear(P-non-linear = 0.008) based on RCS curve analysis, with a threshold value of 12.8. A high NLR above this threshold was significantly associated with increased 90-day mortality rate after adjustment for covariates(HR = 1.535, 95%CI:1.196–1.968,P < 0.001). Conclusion: The role of NLR as a risk factor in predicting 90-day all-cause mortality in ARF patients highlights its potential clinical usefulness in assessing patient prognosis.