Neutrophil-to-lymphocyte ratio is associated with diabetic peripheral neuropathy in type 2 diabetes patients

Highlights

• T2DM patients with higher NLR levels tend to have higher NVC and VPT results.

• T2DM patients with higher NLR levels are more likely to develop DPN.

• NLR is related to DPN, VPT, NCV, age and FPG in T2DM patients.

• NLR could be a predictor of DPN.

Abstract

Objective

Diabetic peripheral neuropathy (DPN) had been demonstrated as a chronic inflammation state and one of the most common complications of type 2 diabetes mellitus (T2DM). Neutrophil-to-lymphocyte ratio (NLR) is a novel marker to reflect many kinds of chronic inflammation disease including diabetes. We aim to evaluate the association between NLR and DPN and to determine whether NLR could be a new indicator of DPN in type 2 diabetes patients.

Methods

We retrospect the consecutive medical files of T2DM patients. Nerve conduction velocity (NCV), vibration perception threshold (VPT) and the data for complete blood count were recorded. Patients were divided into tertiles based on admission NLR values. Clinical parameters were firstly compared among groups. Then, logistic regression and ROC analysis were performed.

Results

Percentages of DPN were 42.60%, 54.97% and 65.50%, in the low, middle and high tertile, respectively (n = 72, 94 and 112, p < 0.05). VPT values were 13.75 ± 7.97, 15.01 ± 9.60 and 16.78 ± 10.92, respectively, (p < 0.05). NCV in different nerves decreased with the increase of NLR (p < 0.05). After adjusting potential related factors, NLR was still related to status of DPN in the logistic regression (r = 1.743, p = 0.001). Area under ROC was 0.619 (p < 0.001).

Conclusion

The present study showed that T2DM patients with higher NLR levels might be more likely to develop peripheral neuropathy complication. NLR levels grow with the increase of NCV and VPT results. As a predictor of DPN, NLR could be used in clinical practice to help doctors understand the level of DPN progression.

Introduction

Type 2 diabetes (T2DM) is a major public health problem worldwide. It is estimated that 366 million people will be affected by T2DM till the year of 2030 [1], [2]. Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes. The lifetime incidence of DPN is approximately 45% for patients with type 2 diabetes mellitus and 54–59% for patients with type 1 diabetes mellitus [3], [4]. In China, peripheral neuropathy is demonstrated to be popular among diabetics, pre-diabetics and even among normal population [5]. Therefore, emphasis should be laid on effective surveillance, early detection and diagnosis of DPN.

Pathological researches and laboratory studies have shown that low-level systemic inflammation has been implicated as the underlying mechanism responsible for the development of T2DM and subsequent complications [6], [7], [8]. However, the costs and technical difficulties associated with detecting these inflammatory markers in daily clinical practice have limited their use. Recently, a novel inflammatory biomarker has been generated to reflect both innate immune response (mediated by neutrophils) and adaptive immune response (mediated by lymphocytes) [9]. As an easily measurable laboratory index, neutrophil-to lymphocyte ratio (NLR) has been proposed as an indicator of systemic inflammation [10], [11], a risk factor of mortality after a major cardiac event and a predictor of cancer outcome [12], [13]. It was also defined as a potential biomarker of inflammation in diabetes and its complications, such as macro-vascular and nephropathy disease [14], [15].

The progression in DPN was traditionally clinically characterized by the development of vascular abnormalities. We therefore want to see if NLR could reflect DPN progression as well as vascular complications. To date, as far as we know, no study has specifically evaluated the relationship between NLR and DPN. Since the degree of DPN is assessed by nerve conduction velocity (NCV, detected by electromyogram (EMG)) and vibration perception threshold (VPT), we hypothesized that the NLR is associated with the results of VPT and EMG and could be increased during the progression of DPN. Hence, the purpose of the present study was to evaluate the association between NLR and DPN and to determine whether NLR could be a new indicator of DPN in type 2 diabetes patients.