Predictive value of neutrophil-to-lymphocyte ratio in mortality of critically ill patients with atrial fibrillation: a retrospective analysis of the Medical Information Mart for Intensive Care IV Database

Abstract

Abstract Objective Inflammation plays an important role in the occurrence and development of atrial fibrillation. We aim to explore the predictive value of neutrophil-to-lymphocyte ratio (NLR) in mortality of critically ill patients with atrial fibrillation (AF). Methods The data of this retrospective cohort study was collected from the MIMIC-IV database. Patients were divided into four groups according to NLR level (cut-off: 7.26) and whether they were diagnosed with AF. The primary outcome of our study was in-hospital mortality. Secondary outcomes included 30-day mortality, 90-day mortality, and 1-year mortality. Restricted cubic spline curve to show the relationship between NLR and in-hospital mortality. Cox Survival analysis and cox regression models were used to assess the association between NLR and mortality. Results A total of 20,707 patients were eligible for analysis. Restricted cubic spline curve showed that NLR level was associated with the lowest risk of in-hospital mortality was 7.26 in all patients, 7.22 in non-AF patients and 7.67 in AF patients. Cox Survival analysis curves showed that patients with AF combined with high-level NLR (Group 4) had higher all-cause mortality compared with other groups. The results of multivariate analysis showed that high NLR was an independent risk factor for poor prognosis in AF patients. The association was consistent among patients in different ICU types. Conclusions Critically ill patients with AF comorbidity and elevated levels of NLR had higher risks of mortality. Moreover, high NLR was an independent risk factor for poor prognosis in AF patients. However, further prospective studies are still needed to reveal this relationship.