Sibutramine and fat distribution: is there a role for pharmacotherapy in abdominal/visceral fat reduction?

Visceral adiposity has a strong and independent association with obesity and its related co-morbidities, particularly metabolic complications such as cardiovascular disease and type II diabetes. Waist circumference and waist-to-hip ratio (WHR) are both secondary indicators of visceral obesity. This paper examines the effect of sibutramine, a new serotonin and noradrenaline re-uptake inhibitor, on weight reduction and changes in fat distribution. A meta-analysis of four long-term, placebo-controlled, double-blind studies showed significantly greater mean decreases in waist circumference in sibutramine-treated subjects compared with placebo (P < 0.001). Similar results were seen for WHR, with 15 mg sibutramine daily producing a significant reduction of 0.02 compared with placebo (P < 0.02). Changes in fat distribution have been examined using computerised tomography (CT) scans as part of the Sibutramine Trial of Obesity Reduction and Maintenance (STORM). Preliminary results showed a mean weight loss from baseline of 11.2 +/- 6.3 kg after 6 months of 10 mg sibutramine treatment. Decreases in total abdominal fat (18%), total subcutaneous fat (17%) and total visceral fat (22%) were observed, and there was a significant increase in the subcutaneous-to-visceral fat ratio (P = 0.04). These changes in fat levels and distribution were associated with improvements in related risk factors such as fasting blood glucose and insulin levels, and blood pressure. In conclusion, sibutramine produces statistically and clinically significant decreases in waist circumference and WHR, and preferentially reduces visceral fat levels.