Neutrophil-Lymphocyte ratio and Platelet-Lymphocyte ratio as useful predictive markers of prediabetes and diabetes mellitus

Abstract

Aims

Chronic inflammation plays a central role in the development and progression of diabetes, and in the pathogenesis of its complications. The neutrophil–lymphocyte ratio (NLR) and platelet–lymphocyte ratio (PLR) are indicators of subclinical inflammation. Mean platelet volume (MPV) is one of the platelet function indices. We investigated the association of NLR, PLR and MPV with prediabetes and type 2 diabetes mellitus and determine whether or not these are reliable markers for diagnosis.

Materials and methods

Participants were divided into four groups; 1: normal glucose tolerance, 2: impaired glucose tolerance (prediabetic), 3: newly diagnosed diabetic by OGTT. 4: group is previously diagnosed diabetic without complication. Outcomes were compared between groups.

Results

There are significant differences between all groups in NLR (p = 0.004) and PLR (p = 0.021) values. NLR values are significantly higher in prediabetic (1.60 ± 0.85), firstly diagnosed diabetic (1.58 ± 0.78) and clear diabetic (2.07 ± 0.95) groups compared to normal group (1.37 ± 0.69) (mean, SD). PLR values are significantly lower in prediabetic (90.35 ± 44.34) and firstly diagnosed diabetic (86.38 ± 45.24) groups compared to normal group (100.55 ± 48.14) but significantly higher in clear diabetic group (122.45 ± 37.43). There are no significant differences between all groups in MPV values.

Conclusion

Inflammation marker NLR significantly increases in prediabetic and diabetic patients. PLR significantly decreases in prediabetes and early stages of diabetes but increases in later stages. NLR and PLR values may be reliable predictive markers in prediabetes and diabetes mellitus.

Introduction

Diabetes mellitus is a frequent chronic disease with high morbidity and mortality [1]. It is now commonly acknowledged that chronic inflammation has a significant role in the development and progression of diabetes mellitus and the pathogenesis of its complications. Several studies have reported an increase in the levels of inflammatory cytokines such as c-reactive protein (CRP), interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-α in patients with diabetes [2], [3]. Inflammatory cytokines are produced by different cell types, released into circulation and have local, central and peripheral effects on different tissue types [4]. Two of the main conditions of prediabetes are impaired levels of fasting glucose (IFG) and impaired glucose tolerance (IGT). IFG is defined as the fasting plasma glucose level ranging from 100 mg/dL (5.6 mmol/L) to 125 mg/dL (6.9 mmol/L). IGT is a condition characterized by a 2-h plasma glucose value in the oral glucose tolerance test, ranging from 140 mg/dL (7.8 mmol/L) to 199 mg/dL (11.0 mmol/L). Another prediabetic condition is glycated haemoglobin (HbA1C) that ranges from 5.7% to 6.4% [5]. Macrovascular complications are twice as common in people with IGT as in normoglycemic individuals [6]. It has been reported that patients with IGT have a high risk of developing type 2 diabetes mellitus (T2DM) but the progression of this disease can be slowed through lifestyle changes related to diet and physical activity [7]. Therefore, it is important to perform an oral glucose tolerance tests (OGTT) on individuals with a risk of diabetes to identify the presence of high levels of IGT or diagnose manifest diabetes.

Recently, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have emerged as new inflammatory biomarkers of T2DM [8], [9], [10].

In addition, it has been suggested that the mean platelet volume (MPV) is a marker that is associated with the number and activity of platelets. It is reported that the MPV level to be lower in high-grade inflammatory conditions such as active rheumatoid arthritis, acute attacks of familial Mediterranean fever and active chronic obstructive pulmonary diseases [11]. This study investigated and compared the NLR, PLR, MPV and certain biochemical levels of participants with normal tolerance (NGT), IGT, newly diagnosed diabetes and previously diagnosed manifest diabetes.