The long-term predictive value of the neutrophil-to-lymphocyte ratio in Type 2 diabetic patients presenting with acute myocardial infarction

Abstract

Background: Patients with diabetes mellitus have worse long-term outcomes after acute myocardial infarction (AMI) than non-diabetics. This may be related to differential contribution of neutrophil and lymphocyte to inflammation during AMI in diabetics vs. non-diabetics. We aim to determine the predictive value of neutrophil-to-lymphocyte ratio (NLR) for major adverse events post-AMI in Type 2 diabetics vs. non-diabetics. Methods and Results: A total of 2559 consecutive patients admitted for AMI (61 ± 14 years, 73% male and 43% diabetic) were analyzed. A complete blood count was obtained and the NLR computed for each patient on admission. Across the cohort, the 1-year reinfarction rate was 8.4% (n = 214) and 1-year mortality was 14.5% (n = 370). Univariate determinants of the composite endpoint included age, hypertension, hyperlipidemia, smoking, revascularization and NLR (P < 0.001 for all). The cohort was divided into NLR quartiles. Admission NLR was significantly higher in the diabetic group, 5.2 ± 5.8 vs. 4.6 ± 5.4 (P = 0.007). A step-wise increase in the incidence of the composite endpoint was noted across NLR quartiles for diabetic subjects; hazard ratio (HR) was 2.41 for fourth vs. first quartile (95% confidence interval = 1.63-3.53, P < 0.001). Multivariate analysis of the diabetic group showed that NLR remains as an independent predictor of the composite endpoint (adjusted HR = 1.53, 95% confidence interval = 1.00-2.33, P = 0.048). However, in non-diabetics, HR for NLR was not significant (P = 0.35). Conclusions: Increased NLR post-AMI is an independent predictor of major adverse cardiac events in diabetics. Monitoring this easily obtainable new index allows prognostication and risk stratification. © The Author 2012. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved.