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

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.

Higher Serum Uric Acid Levels Are Associated With an Increased Risk of Vision-Threatening Diabetic Retinopathy in Type 2 Diabetes Patients

“… 8 In addition, in a cross-sectional study of 1749 diabetic participants in Beijing, a higher SUA level was an independent protective factor for DR. 9 Moreover, a meta-analysis of nine studies and a recent study conducted in China did not demonstrate a strong association between SUA levels and DR. 18 , 19 Another study showed a poor correlation of SUA with retinal nerve fiber layer and macular thickness among T2D patients without DR or with NPDR. 20 In their study, the SUA levels of NPDR participants were significantly lower than those of participants without DR. 20 In our study sample, however, no significant difference was observed in SUA levels between patients with sub-VTDR and no DR.…”

Effects of Uric Acid on Diabetes Mellitus and Its Chronic Complications

“…In Chinese patients with T2DM, reduction in urinary uric acid excretion (UUAE) is an independent risk factor for DR [91]. Elevated SUA levels are significantly associated with albuminuria and DR severity [92], but not with the retinal nerve fibre layer or macular thickness [93]. A study reported that increased SUA levels were associated with an increased severity of DR in Taiwan [94].…”

Comparison of Serum Biochemical and Haematological Analyses in Patients with Age-Related Macular Degeneration and Diabetic Retinopathy

“…Previous cross-sectional studies of the relationship between serum uric acid level and DR have provided mixed results. While Vinuthinee-Naidu et al showed that serum uric acid levels were not well-correlated to retinal nerve fibre layer and macular thickness among type 2 diabetic patients (Vinuthinee-Naidu et al, 2017) and older studies did not detect a relationship (Segato, 1991;Olukoga, 1991), other studies have shown that serum uric acid levels, diabetes and diabetic retinopathy are strongly correlated (Xia et al, 2014;Causevic et al, 2010). In our study, we found high uric acid levels in the PDR group.…”