Correlation of retinal nerve fibre layer and macular thickness with serum uric acid among type 2 diabetes mellitus

Munisamy-Naidu Vinuthinee-Naidu,Embong Zunaina,Naing Nyi-Nyi,Anuar Azreen-Redzal

doi:10.1186/s12886-017-0486-3

Abstract

BackgroundUric acid is a final breakdown product of purine catabolism in humans. It’s a potent antioxidant and can also act as a pro-oxidant that induces oxidative stress on the vascular endothelial cells, thus mediating progression of diabetic related diseases. Various epidemiological and experimental evidence suggest that uric acid has a role in the etiology of type 2 diabetes mellitus. We conducted a cross-sectional study to evaluate the correlation of retinal nerve fibre layer (RNFL) and macular thickness with serum uric acid in type 2 diabetic patients.MethodsA cross-sectional study was conducted in the Eye Clinic, Hospital Universiti Sains Malaysia, Kelantan between the period of August 2013 till July 2015 involving type 2 diabetes mellitus patients with no diabetic retinopathy and with non-proliferative diabetic retinopathy (NPDR). An evaluation for RNFL and macular thickness was measured using Spectralis Heidelberg optical coherence tomography. Six ml of venous blood was taken for the measurement of serum uric acid and glycosylated haemoglobin (HbA1C).ResultsA total of 180 diabetic patients were recruited (90 patients with no diabetic retinopathy and 90 patients with NPDR) into the study. The mean level of serum uric acid for both the groups was within normal range and there was no significance difference between the two groups. Based on gender, both male and female gender showed significantly higher level of mean serum uric acid in no diabetic retinopathy group (p = 0.004 respectively). The mean serum uric acid was significantly higher in patient with HbA1C < 6.5% (p < 0.031). Patients with NPDR have thicker RNFL and macular thickness compared to patients with no diabetic retinopathy. However, only the RNFL thickness of the temporal quadrant and the macular thickness of the superior outer, inferior outer and temporal outer subfields were statistically significant (p = 0.038, p = 0.004, 0.033 and <0.001 respectively). There was poor correlation between RNFL and macular thickness with serum uric acid in both the groups.ConclusionSerum uric acid showed a poor correlation with RNFL and macular thickness among type 2 diabetic patients.

Highlights

Uric acid is a final breakdown product of purine catabolism in humans
Independent t-test was used for comparison of age, Glycosylated haemoglobin (HbA1C), serum uric acid, retinal nerve fibre layer (RNFL) thickness and macular thickness
The mean level of serum uric acid was significantly higher in those patients with HbA1c < 6.5%

Summary

Introduction

Uric acid is a final breakdown product of purine catabolism in humans. It’s a potent antioxidant and can act as a pro-oxidant that induces oxidative stress on the vascular endothelial cells, mediating progression of diabetic related diseases. Diabetes mellitus is regarded as a pandemic, representing one of the most challenging and major public health problems of the twenty-first century. It has become a global alarming disease not sparing any country posing a serious threat to its economy [1]. Diabetic retinopathy is the commonest microvascular complication of diabetes mellitus It remains the leading cause of preventable blindness across all age-groups and places a significant burden on health services [3]. It is suggested that the functional changes noticed before the vascular pathology develops are due to direct effect of diabetes on the neural retina instead of breakdown of the blood retinal barrier [4]

Methods

Results

Discussion

Conclusion