Correlation Between Glycaemic Indices and Central Foveal Thickness in Diabetic Retinopathy

Abstract

BACKGROUND Diabetes mellitus (DM) is a global epidemic with significant morbidity. Diabetic retinopathy (DR) is a specific microvascular complication of DM which affects around 1 in 3 persons with DM. Epidemiological studies and clinical trials have shown that optimal control of blood glucose can reduce the risk of developing retinopathy and slow its progression. Diabetic Macular Oedema (DME) is a major cause for visual impairment. The aim of the study is to evaluate correlation between glycaemic indices and central foveal thickness in patients with diabetic retinopathy with macular oedema. METHODS Fifty eyes of fifty patients with moderate non-proliferative diabetic retinopathy (NPDR) were enrolled in the study. All patients underwent complete ophthalmic examinations including OCT measurements of central macular thickness (CMT). Patients also underwent FBS, PPBS and glycosylated haemoglobin level tests. The correlation between the CMT and glycaemic indices was noted and evaluated. RESULTS Out of the fifty patients, males accounted for 32 and females 18. The mean age of patients with DME was 57.31 ± 6.32 and patients without DME was 60.60 ± 4.32 (range, 40-70 years). The duration of the study was 8 months. The mean value of HbA1c was 9.07 ± 2.01 in patients with DME and without DME it was 5.58 ± 0.34 (range, 5.2-14.8). The mean central retinal thickness was 409.66 ± 127.18 μm in patients with DME and 205.13 ± 7.94 in patients without DME (range, 186-812 μm). Univariate Analysis revealed that the DME diagnosed by OCT in diabetes was not statistically significant with age (p value-0.073). Whereas it was statistically significant with HbA1c (p value-0.0001), Fasting blood sugar (p value-0.0001), post prandial blood sugar (p value-0.0001). The HbA1c level (>7%) showed a significant (p value-0.001) and positive association with macular thickness in OCT. CONCLUSIONS In patients with HbA1c of above 7% had an increased chance of macular thickness (DME) as measured by OCT, is statistically significant and in patients with poor metabolic control (FBS, PPBS) is associated with macular oedema. Good sugar control decreased the risk of diabetic macular oedema.