The Platelet-to-Lymphocyte Ratio Predicts Diabetic Retinopathy in Type 2 Diabetes Mellitus

Abstract

Introduction

As a severe and specific neurovascular complication of type 2 diabetes mellitus (T2DM), diabetic retinopathy (DR) remains the leading cause of vision loss and preventable blindness in adults aged 20 to 74. The pathogenesis of DR is not completely understood, however, studies indicate that chronic inflammation plays a significant role. Emerging evidence suggests that the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), and the monocyte-to-lymphocyte ratio (MLR) are novel potential inflammatory response markers. The purpose of this study was to investigate the relationships between the NLR, PLR, MLR, and DR.

Patients and Methods

290 patients who had been diagnosed with T2DM participated in the study. Patients were categorized into three groups: 142 control subjects with T2DM, 124 subjects with nonproliferative diabetic retinopathy (NPDR), and 24 patients with proliferative diabetic retinopathy (PDR). Characteristics, laboratory data, as well as NLR, PLR and MLR levels of the study groups were compared.

Results

In patients with DR, the median NLR, PLR, and MLR were significantly higher than in patients without DR (p = 0.012, p < 0.001, and p = 0.043, respectively). In the post hoc analysis, there was no correlation between the severity of retinopathy and the increase in NLR or PLR. Multiple logistic regression revealed that the PLR was an independent risk factor for DR (odds ratio [OR]: 1.020, 95% confidence interval [CI]: 1.010–1.029 p = 0.026). Based on the receiver operating characteristic (ROC) curve, the cutoff value of PLR as an indicator for diagnosing DR was estimated to be 129.65, with a sensitivity and specificity of 53.4% and 76.1%, respectively, and an area under the curve of 0.668 (95% CI: 0.605–0.730, p < 0.001).

Conclusion

Our findings suggest that PLR may be an independent risk factor for evaluating DR in type 2 diabetes patients.

Keywords:

• type 2 diabetes mellitus
• diabetic retinopathy
• neutrophil-to-lymphocyte ratio
• platelet-to-lymphocyte ratio
• monocyte-to-lymphocyte ratio
• inflammation

Abbreviations

DM, diabetes mellitus; DR, diabetic retinopathy; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio; MLR, monocyte-to-lymphocyte ratio; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy; ROC, Receiver operating curve; OR, odds ratio; FFA, fundus fluorescein angiography; OCT, optical coherence tomography; OCTA, optical coherence tomography angiography; IBD, bowel disease; AS, ankylosing spondylitis; RA, rheumatoid arthritis; DPN, diabetic peripheral neuropathy; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; HbA1c, hemoglobin A1c; TBL, total bilirubin; Scr, serum creatinine; BUN, blood urea nitrogen; TG, triglycerides; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; HGB, hemoglobin; WBC, white blood cell; Hgb, hemoglobin; OS, Oxidative stress; ROS, reactive oxygen species; PKC, protein kinase C; AGEs, advanced glycosylation end products; CAR, C-reactive protein to serum albumin ratio; PRRs, pattern recognition receptors; TLRs, Toll‐like receptors; IL-1β, interleukin1β; IL-6, interleukin-6; IL-8, interleukin-8; IL-2, interleukin-2; TNF-α, tumor necrosis factor-α; MCP1, monocyte chemotactic protein-1; NSAIDs, non-steroidal anti-inflammatory drugs; VPs, artery vulnerable plaques; DKI, diabetic kidney injury.

Data Sharing Statement

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Ethics Approval and Consent to Participate

The study complies with the Declaration of Helsinki and was approved by the Ethics Committee of Chengdu Fifth People’s Hospital.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests in this work.

Additional information

Funding

This study was supported by the Scientific Research Project of the Health and Family Planning Commission of Sichuan Province [Grant No. 18PJ352], the Scientific Research Project of the Health and Family Planning Commission of Chengdu Municipal [Grant Nos. 2018094 and 2018090], and the Scientific Research Fund of Chengdu Fifth People’s Hospital [Grant No.GSPZX2022-19].