Diabetic nephropathy with and without retinopathy: comparison between urine and serum vascular endothelial growth factor

Aim To evaluate vascular endothelial growth factor (VEGF) levels in serum and urine among diabetic nephropathy (DN) patients with and without diabetic retinopathy (DR). Methods This is a cross-sectional study involving stage 3 and 4 DN patients. A fundus examination was done to determine the DR status. VEGF levels were measured using VEGF-A ELISA kits. Serum creatinine, glycated hemoglobin (HbA1c), and urine protein creatinine index (UPCI) were analyzed per laboratory protocol. Clinical data collected includes height, weight, visual acuity, fundus photo, and macula thickness measured by the optical coherence tomography. Results Seventy-nine patients were divided into group 1: DN with no DR (n = 45.57%) and group 2: DN with DR (n = 34.43%). The two groups were equally distributed in age, gender, ethnicity, duration of diabetes, and smoking status. Mean serum VEGF (244.9 pg/mL), urine VEGF (230.4 pg/mL), and HbA1c (7.6%) were significantly higher in group 2. Mean serum to urine VEGF ratios were 0.72 in group 1 and 1.06 in group 2. Poorer renal function was seen in group 2, although the UPCI was not significantly different. There was no significant correlation between serum and urine VEGF levels and between serum VEGF and other parameters. Conclusion The occurrence of DR in patients with DN is associated with higher mean serum than urine VEGF levels, as compared to lower serum to urine ratio of VEGF levels in DN patients without DR.