The Relationship Between the Monocyte-to-High-Density Lipoprotein Cholesterol Ratio and Platelet Volume Indices With Diabetic Retinopathy

Aim This study aims to evaluate the roles of monocyte count-to-high-density lipoprotein (HDL) cholesterol ratio (MHR) and platelet volume indices (PVI) in predicting diabetic retinopathy (DR) in patients diagnosed with type 2 diabetes mellitus (DM) and to explore new methods for early prediction of retinopathy. Methods This prospective study included 120 patients aged over 18 years with type 2 DM diagnosed according to the American Diabetes Association criteria, along with a control group of 40 healthy individuals. Patients with type 2 DM were divided into three groups: 40 without retinopathy, 40 with non-proliferative diabetic retinopathy (NPDR), and 40 with proliferative diabetic retinopathy (PDR). Parameters such as complete blood count, PVI (mean platelet volume, platelet distribution width, plateletcrit, platelet large cell ratio), lipid profile, inflammatory markers (sedimentation rate, C-reactive protein), MHR, renal function tests, and glucose metabolism markers were analyzed alongside demographic, clinical, and laboratory data to assess their associations with DR in both patient and control groups. Results This study investigated the relationship between DR and hematological parameters (PVI, MHR). Hypertension, hyperlipidemia, and chronic kidney disease were common comorbidities. NPDR patients more frequently used metformin and dipeptidyl peptidase (DPP)-4 inhibitors, while PDR patients more often used insulin (p<0.05). Diabetic neuropathy and nephropathy were more prevalent in the PDR group. PDR patients had a significantly longer DM duration. Mean platelet volume (MPV) and platelet large cell ratio (PLCR) were higher in the PDR group. ROC analysis identified MHR (>11.9, 65% sensitivity, 35% specificity) and plateletcrit (PCT<0.29%, 61% sensitivity, 80% specificity) cut-offs for DR prediction. MHR's area under the curve (AUC) was greater than PCT's (p<0.05). MPV differed between PDR and NPDR, but MHR did not differ among DR groups or between DR/non-DR individuals. Glycosylated hemoglobin (HbA1c) and DM duration correlated positively with MHR, which also correlated with leukocyte count. HbA1c and glucose correlated with platelet distribution width (PDW). Each unit increase in DM duration increased MHR 1.13-fold, and each unit increase in HbA1c increased MHR 1.9-fold. Conclusions The duration of DM was significantly longer in patients with PDR compared to those with NPDR and those without retinopathy. MPV and PLCR levels were significantly higher in PDR patients than in NPDR patients. In evaluating the relationship between PVI and MHR for predicting diabetic retinopathy, significant cut-off values of MHR and PCT were found to be predictive indicators of diabetic retinopathy.