Neutrophil to lymphocyte ratio might help prediction of acute myocardial infarction in patients with elevated serum creatinine.

Background and Objective: Diagnostic performance of troponin assays is affected by renal insufficiency. Neutrophil to lymphocyte ratio(NLR) is an independent predictor of acute coronary syndrome. Our objective was to evaluate performance of NLR in diagnosing acute myocardial infarction (AMI) among patients with elevated serum creatinine.
Methods: Patients with elevated creatinine levels evaluated for coronary artery disease were included (n=284). Patients were divided into two groups according to having AMI or non-specific chest pain. AMI diagnosis was made based on clinical and laboratory data, including serial EKG and cardiac enzymes, ECHO and coronary angiography.
Results: Troponin, neutrophil, and NLR were found to be higher in patients with AMI, compared to patients without AMI (P= 0.001, P= 0.001 and P=0.028, respectively). ROC curve analysis for NLR in diagnosing AMI was significant (AUC: 0.607; P=0.003). Sensitivity, specificity, LR +, LR-, PPV and NPV for NLR>7.4 were found as 42.3%, 74.7%, 1.68%, 0.77%, 77% and 40%, respectively. Logistic regression analysis revealed that patients whose NLR>7.4 were 2.18 times as likely to have AMI.
Conclusions: NLR can be used as an independent predictor of AMI in patients with renal insufficiency. This seems to get more important in the era of high sensitivity troponin assays. Our results might also help in early diagnosis of AMI in this high risk population while serial cardiac enzyme results are pending.