Impact of the Neutrophil-to-Lymphocyte Ratio in Patients With Coronary Artery Disease

We read with deep interest the article “Association between neutrophil-to-lymphocyte ratio and severity of coronary artery disease” by Kaya et al. ¹ The authors ¹ aimed to evaluate the association between neutrophil-to-lymphocyte (N/L) ratio and severity of coronary artery disease (CAD). We would like to make a minor criticism based on their methodology.

Atherosclerosis is a multifaceted disease; however, it is essentially an inflammatory response to various conventional risk factors. Therefore, new studies have focused on inflammatory markers to determine their importance in CAD. ² The complete blood count is an easy technique that can reveal the patient’s blood contents such as the N/L ratio, and it represents the balance between neutrophil and lymphocyte levels. Most of the conditions including traditional risk factors (ie, hypertension, atherogenic lipoproteins, obesity, and hyperglycemia) and many other inflammatory conditions (ie, infection and inflammatory diseases) can change this ratio. ² In the study, there were significant differences between the groups regarding the fasting glucose, high-density lipoprotein cholesterol and creatinine values. These variables may also be responsible for atherosclerosis and may change the N/L ratio. The authors ¹ should have also given height, weight, and body mass index of the study population in order to describe obesity that is a proven risk factor for CAD. On the other hand, the authors ¹ did not analyze the markers of inflammation such as C-reactive protein (CRP), although their role in inflammation was previously reported in patients with CAD. ³ If the CRP levels of these patients (besides the N/L ratio) have had been screened and correlated with the N/L ratio that would provide a better perspective.

We would like to congratulate the authors ¹ to point out N/L ratio in patients with CAD. It seems a novel indicator of systemic inflammation and atherogenesis, but it should be evaluated together with traditional risk factors and other serum inflammatory markers. Large-scale prospective clinical studies with these recommendations are needed.