Background Obesity is a risk factor for atherosclerosis. One of the health risks for obesity is stroke. Thiazolidinediones, insulin-sensitizing agents, are noted to have an effect on intimal thickness in animal models. We examine in this study whether pioglitazone compared to placebo decrease carotid artery intimal thickness in healthy, obese patients.
Methods Thirty-three healthy, ethnically diverse, obese volunteers has been randomly assigned into three groups. Group A received placebo, and Groups B and C received Pioglitazone 30 mg and 45 mg respectively daily for six months. Carotid artery intimal thickness was measured by the use of ultrasound in both common carotid arteries starting from 2 cm below the carotid artery bifurcation. Anthropometric measurements, CAT scan of abdomen and thigh for measurement of regional visceral fat distribution, and intimal thickness measurements were performed before and after 6 months of therapy. Paired student T-tests were used for pair-wise comparison of variables and multiple regression analysis was used to examine the correlation of variables.
Results 18 subjects completed this ongoing study. At baseline, there were no significant differences between their ages in Groups A, B, C: (42 ±5), (43 ±3), (41 ±3) respectively. Their BMIs were not statistically significant in Groups A, B, C: (38 ±2), (40 ±2), (41 ±2). 2 cm Average Carotid artery intimal thickness increased in placebo group by 300 microns (p≤0.01), did not change in Group B (p=NS), and decreased in Group C by 300 microns (p≤0.01). Surprisingly, a statistically negative correlation between adjusted (for BMI) visceral fat and carotid intimal thickness was observed (r=0.40, p≤0.05). However, no significant correlation between age, BMI, and carotid artery intimal thickness was seen.
Conclusion 45 mg of Pioglitazone daily over a period of 6 months reduces intimal thickening. Whether Pioglitazone is effective in prevention of stroke and peripheral vascular disease in high-risk subjects needs further study.