Renal hypouricaemia in insulin treated diabetes mellitus

Abstract

Uric acid metabolism was investigated in 69 insulin-treated male diabetic outpatients and in 23 healthy male subjects, because of a reported coincidence between diabetes and gout. All subjects had normal serum creatinine concentrations and none received diuretic treatments. Compared with normal, the diabetics had significantly lower mean serum uric acid concentrations (0.34 ± 0.08 (SD) mmol/l versus 0.23 ± 0.06 mmol/1, p < 0.001). 17% of the diabetic patients had serum concentrations below the normal mean—2 SD. In contrast, the diabetic patients had a 42% increase in renal uric acid excretion rate ( p <0.01), and an 83% increase in the ratio of uric acid clearance/creatinine clearance ( p < 0.001). These indices of renal uric acid excretion were both positively correlated to fasting blood glucose levels ( r = 0.57, p < 0.001, and r = 0.50, p < 0.001, respectively), to the degree of glycosuria ( r = 0.73, p < 0.001, and r = 0.63, p < 0.001, respectively), and to the magnitude of water diuresis ( r = 0.60, p < 0.001, and r = 0.39, p < 0.01, respectively). The hypouricaemia observed in these insulin-dependent diabetic male subjects may probably be caused by the increased renal excretion of uric acid in the presence of hyperglycaemia. The study gave no evidence of increased serum uric acid concentrations in insulin-dependent diabetics. It is therefore likely that any coincidence between gout and diabetes derives from other coexisting serum uric acid raising factors.