Usefulness of the neutrophil to lymphocyte ratio in predicting long-term mortality in ST segment elevation myocardial infarction

Neutrophil to lymphocyte ratio (N/L) has been associated with poor outcomes in patients who underwent cardiac angiography. Nevertheless, its role for risk stratification in acute coronary syndromes, specifically in patients with ST-segment elevation myocardial infarction (STEMI), has not been elucidated. We sought to determine the association of N/L maximum value (N/L max) with mortality in the setting of STEMI and to compare its predictive ability with total white blood cell maximum count (WBC max). We analyzed 515 consecutive patients admitted with STEMI to a single university center. White blood cells (WBC) and differential count were measured at admission and daily for the first 96 hours afterward. Patients with cancer, inflammatory diseases, or premature death were excluded, and 470 patients were included in the final analysis. The association between N/L max and WBC max with mortality was assessed by Cox regression analysis. During follow-up, we registered 106 deaths (22.6%). A positive trend between mortality and N/L max quintiles was observed; 6.4%, 12.4%, 11.7%, 34%, and 47.9% of deaths occurred from quintiles 1 to 5 (p <0.001), respectively. In a multivariable setting, after adjusting for standard risk factors, patients in the fourth (Q4 vs Q1) and fifth quintile (Q5 vs Q1) showed the highest mortality risk (hazard ratio 2.58, 95% confidence interal 1.06 to 6.32, p = 0.038 and hazard ratio 4.20, 95% confidence interal 1.73 to 10.21, p = 0.001, respectively). When WBC max and cells subtypes were entered together, N/L max remained as the only WBC parameter; furthermore, the model with N/L max showed the most discriminative ability. In conclusion, N/L max is a useful marker to predict subsequent mortality in patients admitted for STEMI, with a superior discriminative ability than total WBC max.