Introduction: Neutrophil-to-lymphocyte ratio (NLR), which is an essential marker of inflammation, has been shown to be associated with adverse outcomes in various cardiovascular diseases in the literature. In this study we sought to evaluate the association between NLR and prognosis of acute pulmonary embolism (APE).
Material and methods: We retrospectively evaluated blood counts and clinical data of 142 patients with the diagnosis of pulmonary embolism (PE) from Ondokuz Mayis University Hospital between January 2006 and December 2012. The patients were divided into two groups according to NLR: NLR < 4.4 (low NLR group, n = 71) and NLR ≥ 4.4 (high NLR group, n = 71).
Results: Massive embolism (66.2% vs. 36.6%, p < 0.001) and in-hospital mortality (21.1%, 1.4%, p < 0.001) were higher in the high NLR group. In multivariate regression analysis NLR ≥ 5.7, systolic blood pressure (BP) < 90 mm Hg, serum glucose > 126 mg/dl, heart rate > 110 beats/min, and PCO2 < 35 or > 50 mm Hg were predictors of in-hospital mortality. The optimal NLR cutoff value was 5.7 for mortality in receiver operating characteristic (ROC) analysis. Having an NLR value above 5.7 was found to be associated with a 10.8 times higher mortality rate than an NLR value below 5.7.
Conclusions: In patients presenting with APE, NLR value is an independent predictor of in-hospital mortality and may be used for clinical risk classification.