Endocrine Abstracts

Objectives: Diabetic retinopathy, is the most frequent cause of new cases of blindness among adults aged 20–74 years in developed countries. In 15 of the 23 studies in developing countries and in ethnic minority groups within developed countries, the prevalence of diabetic retinopathy was over 35%. In developed countries, only 2 of 16 studies reported a prevalence of 35% or over. Variation in neither population demographics nor method of retinopathy assessment appeared to account for these differences in prevalence. Serum uric acid is one of the major sources of oxidative stress thru generation of free radicals and exhibits pro-inflammatory actions. This study aims to investigate the association of serum uric acid levels and diabetic retinopathy.

Methodology: Consecutive patients at the Diabetes Clinic at East Avenue Medical Center, diagnosed with Type 2 Diabetes Mellitus by the ADA criteria for diabetes from August 2019 to May 2020 were recruited. We excluded patients with pre-diabetes, Type 1 DM, diabetes induced by steroid use and other endocrine diseases, gestational diabetes, significant co-morbidities (cancer, COPD, decompensated heart/liver failure, ESRD on HD), kidney transplanted patients, renal artery stenosis, autoimmune kidney diseases and patients who undergone cataract or any retinal surgeries. Demographic, medical and laboratory data were obtained. Blood examinations were performed in the same diagnostic center by the same device. All recruited patients were examined by one retina fellow to prevent inter-observer variability.

Results: 117 (67 with DR and 50 no DR) patients were analyzed. The mean age of patients with diabetic retinopathy was younger (55.73 + 8.18) than those patients without diabetic retinopathy (56.34 + 11.31) however the difference between the two groups was not statistically significant (P= 0.736). The mean serum uric acid level was 6.44 + 1.54 mg/dl in patients with DR whereas it was 6.10 + 1.59 mg/dl in those without DR. The levels however were not statistically significant (P=0.249). Using the binary logistic regression, duration of DM, presence of anemia as well proteinuria and low estimated glomerular filtration rate (eGFR) were independently associated with DR (P=0.006, 0.008, 0.012 and 0.037, respectively).

Conclusion: Serum uric acid levels were not associated with diabetic retinopathy, but it was shown in this study that there was a higher concentration of uric acid levels in patients with more severe retinopathy. Duration of diabetes, anemia, lower eGFR and presence of proteinuria reflecting chronic kidney disease were independently associated with the presence of diabetic retinopathy.