Hypouricemia and hyperuricemia in type 2 diabetes: two different phenotypes

BACKGROUND AND DESIGN: Conflicting data exist about uric acid levels in type 2 diabetes mellitus, as low levels were found in diabetic patients, while elevated serum uric acid is a feature of hyperinsulinemia and impaired glucose tolerance. The present study was addressed to evaluate the relation between uric acid and metabolic parameters, creatinine clearance and albumin excretion rate in a cohort of type 2 diabetic patients. RESULTS: Hyperuricemic patients were older and had higher values of body mass index (BMI), systolic and diastolic blood pressure, triglycerides, albumin excretion rate, C-peptide and prevalence of hypertension, metabolic syndrome and macroalbuminuria and lower values of high-density lipoprotein (HDL)-cholesterol, creatinine clearance and glycated haemoglobin (HbA1c). The correlations between uric acid levels and triglycerides, BMI, systolic blood pressure, albumin excretion rate, C-peptide, creatinine clearance, HDL-cholesterol and HbA1c remained significant in a multiple regression analysis after adjustment for age, sex and duration of diabetes. After performing multiple logistic regression analyses, uric acid levels were independently associated with hypertension [odds ratio (OR) = 1.8; 95% confidence interval (CI) 1.6--2], after adjustment for age, sex, duration of diabetes and macroalbuminuria (OR = 1.5; 95% CI 1.1--2.0), after adjustment for age, sex, HbA1c levels, creatinine clearance, duration of diabetes and blood pressure levels and the metabolic syndrome (OR = 1.6; 95% CI 1.5--1.8), after adjustment for age, sex and creatinine clearance. CONCLUSIONS: In type 2 diabetes, hyperuricemia seems to be associated with the insulin-resistant syndrome and with early onset or increased progression to overt nephropathy, while hypouricemia is associated with worse metabolic control, hyperfiltration and a late onset or decreased progression to overt nephropathy.