Comparison of metabolic effects of orlistat and sibutramine treatment in Type 2 diabetic obese patients.

AIM: The aim of our study was to comparatively evaluate the efficacy and safety of orlistat and sibutramine treatment in obese diabetic patients of both sexes, with specific attention to metabolic pattern-induced changes and cardiovascular effects.

METHODS: Patients were enrolled, evaluated, and followed in 3 Italian Centres of Internal Medicine. We evaluated 144 obese diabetic patients. All were required to have been diagnosed as being diabetic for at least 6 months, and had glycaemic control with diet alone or diet and oral hypoglycaemic agents. We administered orlistat (360 mg/d) or sibutramine (10 mg/d) in a randomized, controlled, double-blind clinical study, and evaluated anthropometric variables, glycaemic control, blood pressure and heart rate (HR) during 12 months of this treatment.

RESULTS: A total of 141 (69 males and 72 females; 35 males and 36 females, aged 53 +/- 5 yr with orlistat; 34 males and 36 females, aged 51 +/- 4 yr with sibutramine) completed the 4 weeks on controlled-energy diet and were randomized to double-blind treatment with orlistat (n=71) or sibutramine (n=70). Significant body mass index (BMI) improvement was present after 6 (p<0.05), 9 (p<0.02), and 12 (p<0.01) months in both groups. Significant waist circumference (WC), hip circumference (HC), and waist/hip ratio (W/H ratio) improvement was observed after 12 months (p<0.05, respectively) in both groups. Significant HbA1c decrease was obtained after 6 (p<0.05), 9 (p<0.02), and 12 (p<0.01) months in both groups. After 9 and 12 months, mean fasting plasma glucose (FPG) and post-prandial plasma glucose (PPG) levels were significantly decreased in both groups (p<0.05 andp<0.02, respectively). Significant systolic blood pressure (SBP) and diastolic blood pressure (DBP) improvement (p<0.05) was present in the orlistat group after 12 months. No significant change in blood pressure measurements was observed in the sibutramine group during the study. No significant HR variation was obtained during the study in either group. Of the 133 patients who completed the study, 33.8% of patients in the orlistat group and 13.2% of patients in the sibutramine group had side effects (p<0.05 vs orlistat group). Side effect profiles were different in the two treatmen groups. All orlistat side effects were gastrointestinal events. Sibutramine caused an increase in blood pres sure (both SBP and DBP) in one patient, but it was controlled by anti-hypertensive treatment. The vita min changes were small and all mean vitamin and beta-carotene values stayed within reference ranges. No patients required vitamin supplementation.

CONCLUSIONS: Both orlistat and sibutramine were effective on anthropometric variables and on metabolic pattern during the 12-month treatment; in our sample, orlistat appears to be slightly more efficacious as an anti-obesity drug, while sibutramine intake was not associated to any cardiovascular effect and was generally better tolerated than orlistat.