Correlation Between Serum Melatonin Level and Other Indicators With Stages of Diabetic Retinopathy

Abstract

Purpose: Diabetic retinopathy is considered the ghost cause of vision deterioration; it is attributed to elevated oxidative stress. Antioxidants, like melatonin, were found to be affected in diabetic retinopathy. In the present paper, we aim to explore melatonin levels in various stages of diabetic retinopathy. Method: Patients with diabetic retinopathy were recruited and divided into 3 groups (non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), and advanced diabetic eye disease). One control group was recruited (diabetics without diabetic retinopathy). Each participant was subjected to full ophthalmological examination, internal medicine evaluation, fluorescein angiography F/A, as well as optical coherence tomography (OCT) to classify the stage of diabetic retinopathy. The laboratory evaluation of melatonin, bilirubin, aspartate transferase AST, alanine transferase ALT, fasting plasma glucose FBG, hemoglobin A1c HA1c, and lipid profile were done. Data were collected and analyzed. Results: Each group includes 60 participants. We found no different sex distribution in the four groups as (P value =0.77), age in the four groups was as follows 58.35±8.56, 55.77±14.43, 59.3±10.73, 60.98± 7.60 years with (P =0.06). For diabetes-associated variables like duration, fasting glucose levels, HA1c, and medications (insulin or oral hypoglycemic), we found this result; increased duration of diabetes with raised levels of FBG, HA1C, and insulin treatment were linked with severe diabetic retinopathy affection (P value <0.0001). When assessing the plasma melatonin levels, the mean melatonin levels were decreased significantly with increased severity of diabetic retinopathy (86.04 ± 2.71, 73.05 ± 6.91, 25.82 ± 2.89, 24.28 ± 2.37 pg/ml) in the studied groups NDR, NPDR, PDR and advanced diabetic retinopathy with (P-value < 0.0001). Decreased melatonin could be a risk factor for diabetic retinopathy. As regards total bilirubin, its mean values decreased significantly with increasing severity of DR (P-value < 0.0001). Conclusion: There is a relation between the levels of serum melatonin and the severity of diabetic retinopathy.