Serum uric acid and progression of diabetic nephropathy in type 1 diabetes

Abstract

Aims: Uric acid (UA) is a risk factor for CKD. We evaluated UA in relation to change in GFR in patients with type 1 diabetes.

Methods: Post hoc analysis of a trial of losartan in diabetic nephropathy, mean follow-up 3 years (IQR 1.5-3.5). UA was measured at baseline. Primary end-point was change in measured GFR. UA was tested in a linear regression model adjusted for known progression factors (gender, HbA_1c, systolic blood pressure, cholesterol, baseline GFR and baseline urinary albumin excretion rate (UAER)).

Results: Baseline UA was 0.339 mmol/l (SD ±0.107), GFR 87 ml/min/1.73 m² (±23), geometric mean UAER 1023 mg/24 h (IQR, 631 - 1995). Mean rate of decline in GFR was 4.6 (3.7) ml/min/year. In the upper quartile of baseline UA the mean decline in GFR from baseline to the end of the study was 6.2 (4.9) ml/min/1.73 m² and 4.1 (3.1) ml/min/1.73 m² in the three lower quartiles of UA, (p = 0.088). In a linear model including baseline covariates (UAER, GFR, total cholesterol, HDL cholesterol) UA was associated with decline in GFR (r² = 0.45, p < 0.001).

Conclusion: Uric acid was weakly associated with decline in GFR in type 1 diabetic patients with overt nephropathy.

Keywords: Albuminuria; Diabetic nephropathy; Glomerular filtration rate; Type 1 diabetes; Uric acid.