The Association of Serum Leptin Level and Anthropometric Measures With the Severity of Diabetic Retinopathy in Type 2 Diabetes Mellitus

This study was performed to determine the association amongst serum leptin level and anthropometric measures with the severity of Diabetic Retinopathy (DR) in subjects with type 2 Diabetes Mellitus (DM). This case-controlled study was conducted within a one-year period, during year 2016, at outpatient retina ophthalmology clinics of Shiraz, southern Iran. Eighty-three patients with type 2 DM, referring for ophthalmoscopy evaluation, were included. Anthropometric measures, serum leptin level, and baseline laboratory assessment was performed for all subjects. Patients were categorized as group 1, consisting of patients with severe Non-Proliferative Diabetic Retinopathy (severe NPDR) and Proliferative Diabetic Retinopathy (PDR) (n = 44), and group 2, consisting of patients without Diabetic Retinopathy (no DR) or mild/moderate NPDR (n = 39). The serum leptin level and anthropometric measures were compared between the two study groups. The correlation between these variables was also assessed. The mean age of the participants was 59.3 ± 6.9 years old. The two study groups were comparable regarding baseline characteristics. Cases of group 1 had significantly higher Erythrocyte Sedimentation Rate (ESR) (P = 0.049) and Systolic Blood Pressure (P = 0.025) when compared with those of group 2. The serum level of leptin was found to be significantly higher in cases of group 1 when compared to those of group 2 (P = 0.003). However, anthropometric measures, including Body Mass Index (BMI) (P = 0.167), Body Adiposity Index (BAI) (P = 0.061), and Waist to Hip Ratio (WHR) (P = 0.220) were comparable between the two study groups. Serum leptin level was positively correlated with BMI (r = 0.819; P < 0.001) and BAI (r = 0.630; P < 0.001) in group 1. Increased serum levels of leptin were associated with advanced stages of DR in subjects with type 2 DM. Serum leptin level might be a better indicator of the effects of obesity on DR, compared to anthropometric measures (BAI or BMI).