The Neutrophil-to-Lymphocyte Ratio Is an Independent Inflammatory Biomarker for Adverse Events in Patients With Atrial Fibrillation: Insights From the Murcia AF Project II (MAFP-II) Cohort Study

Abstract

Background

Systemic inflammation plays a central role in atrial fibrillation (AF). The neutrophil-to-lymphocyte ratio (NLR) is a simple hematological index that has been shown to be associated with prognosis in different pathologies.

Hypothesis

The NLR is associated with an increased risk of adverse events in patients with AF.

Methods

We included a prospective cohort of AF patients who started vitamin K antagonists (VKAs) therapy between July 2016 and June 2018. NLR was assessed at baseline and classified into three categories: low (< 3), moderate (3–5), and high (> 5). During a 2-year follow-up period, all cardiovascular deaths, all-cause deaths, and net clinical outcomes (NCO; either ischemic stroke/transient ischemic attack, major bleeding or all-cause death), were recorded.

Results

A total of 1050 patients were included (51.4% women; median age 77 years). NLR was available in 936 patients: 507 (54.2%) had low NLR (< 3), 239 (25.5%) had moderate NLR (3–5), and 190 (20.3%) had high NLR (> 5). The primary endpoint was significantly increased in the high NLR category (p = 0.002 for cardiovascular death; p < 0.001 for all-cause mortality, and p < 0.001 for NCO), with higher IRRs (all p < 0.001). Multivariate Cox regression analyses showed that high NLR was independently associated with an increased risk of cardiovascular death (aHR: 2.02; 95% CI: 1.04–3.92), all-cause mortality (aHR: 2.51; 95% CI: 1.58–3.97), and NCO (aHR: 1.99; 95% CI: 1.37–2.87), compared to low NLR.

Conclusions

In this prospective AF cohort receiving VKAs, elevated NLR was significantly associated with an increased risk of adverse clinical outcomes. NLR has independent prognostic value beyond other classical risk factors.