Long-term weight loss with sibutramine: a randomized controlled trial.

CONTEXT: Treatment of obesity requires long-term therapy, which can be hampered by difficulties in achieving patient compliance. The effectiveness of sibutramine hydrochloride in treating obesity has been shown in randomized controlled trials.

OBJECTIVE

To compare the effectiveness of 2 distinct sibutramine regimens with each other and with placebo for weight reduction among obese persons.

DESIGN

Randomized, double-blind, parallel-group placebo-controlled trial from April 1997 to September 1998.

SETTING

One hundred eight private practices and 3 outpatient departments of university hospitals in Germany.

PATIENTS: A total of 1102 obese adults (body mass index, 30-40 kg/m(2)) entered the 4-week open-label run-in period with 15 mg/d of sibutramine, 1001 of whom had weight loss of at least 2% or 2 kg were randomized into the 44-week randomized treatment period.

INTERVENTIONS: Patients were randomly assigned to receive 15 mg/d of sibutramine continuously throughout weeks 1-48 (n = 405); 15 mg/d of sibutramine intermittently during weeks 1-12, 19-30, and 37-48, with placebo during all other weeks (n = 395); or placebo for weeks 5-48 (n = 201).

MAIN OUTCOME MEASURE: Weight loss during the randomized treatment period, compared among all 3 groups.

RESULTS

Mean weight loss in the intention-to-treat population during the 44-week randomized treatment period was 3.8 kg (4.0%) in patients receiving continuous therapy (95% confidence interval [CI], - 4.42 to - 3.20 kg) and was 3.3 kg (3.5%) in patients receiving intermittent therapy (95% CI, - 3.96 to - 2.66 kg), vs a mean weight gain of 0.2 kg (0.2%) (95% CI, - 0.60 to 0.94 kg) in patients receiving placebo. Therapeutic equivalence of the 2 active treatments could be shown. Although there was a greater weight loss in the continuous than in the intermittent group, this difference was nonsignificant (P =.28) and the 95% CIs were within the predefined range of therapeutic equivalence-0 +/-1.5 kg (-1.37 to 0.28 for the intent-to-treat population). Overall weight loss during the 48-week period was 7.9 kg and 7.8 kg in the continuous and intermittent groups, respectively, but was 3.8 kg in the sibutramine run-in placebo group. Waist circumference reduction, triglyceride levels, and high-density lipoprotein cholesterol concentrations were also positively influenced by sibutramine treatment. Systolic and diastolic blood pressures were stable across all 3 groups. Overall, adverse events occurred at similar frequencies across all treatment groups, but the proportion was lowest in the group receiving intermittent therapy.

CONCLUSIONS

Sibutramine, administered for 48 weeks to a typically obese population, results in clinically relevant weight loss compared with placebo. Regarding effectiveness, continuous and intermittent sibutramine therapies are equivalent and the safety profiles for both treatments are comparable.