Prognostic Value of Neutrophil to Lymphocyte Ratio in Patients with Acute Pulmonary Embolism: A Restrospective Study

Abstract

Acute pulmonary embolism (PE) is a serious clinical condition characterised by a high mortality rate. Previous studies showed that leukocytosis was associated with recurrences of venous thromboemboli, major bleeding and increased mortality. The aim of the present study was to investigate the prognostic value of neutrophil to lymphocyte ratio (NLR) in patients with acute PE during short term follow-up. A total of 640 patients were screened by I26 code of ICD-9 and 359 patients were included as cases of confirmed acute PE. Admission blood counts and clinical data were obtained from medical charts. The predictors of 30-day mortality were examined. Fifty-one out of 359 patients (14.2%) included in the study died during 30 days follow-up. In multivariate Cox regression analysis systolic blood pressure (HR:0.97 (0.94-0.99 CI95%), p=0.019), diabetes mellitus (HR:3.3 (1.30-8.39 CI95%), p=0.012), CK-MB(HR:1.03 (1.01-1.06 CI95%), p=0.024) and NLR (HR:1.03 (1.01-1.06 CI95%), p=0.008) were predictors of 30-day mortality. An optimal cut-off value of NLR was determined as 9.2 by using ROC curve. Hazards ratio of NLR>9.2 was found to be 3.60 (1.44-9.18 CI95%, p=0.006). NLR>9.2 had a sensitivity, specificity, negative predictive value, and positive predictive value of 68.6%, 80.5%, 93.9% and 36.5%, respectively. NLR on hospital admission may be a predictor of 30-day mortality in acute PE. Since complete blood count is a part of the routine laboratory investigation in the most hospitalised patients use and preliminary promising results of this study, NLR should be investigated in future prospective randomised trials regarding prognostic value in acute PE.