Prognostic value of neutrophil/lymphocyte ratio in patients with pulmonary embolism

Preliminary evidence suggests that inflammation plays a role in the development and prognosis of pulmonary embolism (PE). We used the neutrophil/lymphocyte ratio (NLR) as a measure of systemic inflammation and investigated its association with PE.

A total of 266 patients who were diagnosed with PE and a control group of 124 age- and sex-matched healthy subjects were included in this study. We further classified the PE patients into 2 groups: those who survived and those who died in the first 30 days. Baseline NLR was measured by dividing neutrophil count to lymphocyte count and was compared between the groups.

Median NLR was significantly higher among patients with PE compared to the healthy control group (3.9 (interquartile range (IQR): 5.0) vs. 1.9 (IQR: 0.6), P < 0.001). Of the 266 patients with PE, 16 (6%) died within 1 month. Median NLR was significantly higher among PE patients who died compared to those who survived, as well (3.7 (IQR: 4.3) vs. 9.0 (IQR: 7.9), P < 0.001). The optimal cut-off values, sensitivities, and specificities of NLR for predicting PE and in-hospital mortality of PE were >2.565 and >5.465, 70.3% and 75.0%, and 92.7% and 67.6%, respectively. Multiple logistic regression analysis showed that NLR values of >5.465 could define those patients with a mortal clinical course independently (odds ratio: 13.446, 95% confidence interval: 3.141-57.566, P < 0.001).