Decreases in serum uric acid by amelioration of insulin resistance in overweight hypertensive patients: Effect of a low-energy diet and an insulin-sensitizing agent

Background: Hyperuricemia and hyperinsulinemia/ insulin resistance are commonly seen in obese subjects and hypertensive patients. To clarify whether the insulin resistance plays a role in hyperuricemia, we investigated alterations in serum uric acid (UA) concentrations during treatment with a low-energy diet or an insulin-sensitizing agent in overweight hypertensive patients. Methods: Twenty-eight overweight hypertensive patients (14 men and 14 women, mean age 61 +/- 2 years) were assigned to a weight reduction program with a low-energy diet (3360 kJ/day for 3 weeks, n = 14) and to treatment with troglitazone (200 mg twice daily for 8 weeks, n = 14). Measurements of body weight, blood pressure (BP), serum UA, and a 75-g oral glucose tolerance test were performed at baseline and the end of the intervention periods. Results: Body weight and BP decreased significantly in the diet group but not in the troglitazone group at the end of the intervention periods. Levels of blood glucose, plasma insulin, and homeostasis model assessment-insulin resistance index (HOMA-R) improved similarly in the two groups. Serum UA concentration decreased by treatment both in the diet (0.4 +/- 0.2 mg/dL, P <.05) and troglitazone groups (1.0 +/- 0.2 mg/dL, P <.001). Conclusions: The amelioration of insulin resistance by either a low-energy diet or troglitazone decreased the serum UA level in overweight hypertensive patients. Insulin resistance or hyperinsulinemia, independent of body weight and BP, may play an important role in UA metabolism in multiple risk factor syndrome.