Evaluation of rosiglitazone administration on cardiovascular function in severe obesity.

Background: Obese patients have myocardial structural and functional alterations related to insulin resistance.

Hypothesis: The purpose of the study was to analyze the effects of rosiglitazone, an insulin sensitizer agent, on cardiac morphometry and functioning.

Methods: In 2 groups of sex- and age-matched, nondiabetic, obese patients (5 men and 7 women, age 19-51 y; group A: body mass index [BMI] 40.6 +/- 3.4 kg/m(2); group B: BMI 42.6 +/- 2.7 kg/m(2)), we evaluated the basal insulin sensitivity index (HOMA[IS]), body composition by bioelectrical impedance analysis and 24-h blood pressure monitoring. Furthermore, all patients underwent conventional 2-Dimensional and color Doppler echocardiography, and pulsed-wave tissue Doppler imaging (TDI). After the baseline evaluation, all patients were put on a hypocaloric diet (70% basal metabolic rate) plus placebo if they were in group A, or plus rosiglitazone (4 mg twice daily; Avandia [GlaxoSmithKline plc., Brentford, Middlesex, United Kingdom]) if they were in group B, for 6 mo.

Results: Significant decreases in body weight, total fat mass, BMI, and systolic blood pressure were registered in both groups. Rosiglitazone administration appeared more efficient in improving HOMA(IS) (mean difference: 0.30 +/- 0.19 versus 0.11 +/- 0.21, p < 0.05). Left ventricular (LV) diastolic diameter (49.4 +/- 7.7 versus 52.3 +/- 5.4 mm, p < 0.05) and E wave (0.89 +/- 0.18 versus 0.99 +/- 0.20 m/sec, p < 0.05) increased in the rosiglitazone group due to a rise in preload and water content without peripheral edema. The increase in systolic (Sa) wave velocity in both groups was probably a result of the general improvement in insulin metabolism and the decrease in blood pressure.

Conclusions: We confirmed the positive effect of rosiglitazone on glucose metabolism in obese, nondiabetic patients, but changes in insulin sensitivity did not explain the cardiac effects produced by further mechanisms.