Elevated level of uric acid, but not glucose, in aqueous humor as a risk factor for diabetic macular edema in patients with type 2 diabetes.

To determine the association of uric acid (UA) and glucose in aqueous humor with diabetic macular edema (DME) in patients with type 2 diabetes.Patients with DME or diabetes mellitus without retinopathy were enrolled from August 2016 to December 2020. Non-diabetic patients with age-related cataract or age-related macular degeneration were included as controls.A total of 585 eyes from 585 patients were included for this study. Statistical analysis showed that aqueous UA was associated with central retinal thickness (r=0.39, P<0.0001), with higher levels of UA in severe DME and lower levels in mild DME, suggesting an ocular source of UA from the diabetic retina. Aqueous UA (odds ratio [OR], 6.88 [95% CI, 2.61-18.12]), but not aqueous glucose (0.95 [95% CI, 0.73-1.23]) or serum UA (0.90 [95% CI, 0.66-1.23]), was a stronger predictor for DME than duration of DM (1.26 [95% CI, 1.12-1.42]) or hemoglobin A1c (1.35 [95% CI, 0.99-1.83]). If aqueous UA (<2.46 mg/dl) and aqueous glucose (<6.43 mmol/L) were used as reference, high UA (≥2.46 mg/dl) alone was associated with 5.83-fold increase in risk of DME, but high glucose (≥6.43 mg/dl) alone was not associated with DME.Increased aqueous UA, but not glucose, is an independent risk factor for DME. These data suggest that an intravitreal UA-lowering therapy could be beneficial for DME.