Behavior therapy and sibutramine in adolescents - Assessment and Treatment of Obesity - Author Abstract

Nutrition Research Newsletter, May, 2003

Adolescent obesity is rapidly becoming a national public health problem. The prevalence of this disorder increased from 5% to 11% from the 1980s to 1994 and to 15.5% by 2000.

This increase has been accompanied by a dramatic increase in type 2 diabetes and related health complications. There has been relatively little controlled research on the treatment of adolescent obesity, and most studies have reported that participants remain obese at the end of therapy. Weight loss medications, including sibutramine and orlistat, facilitate weight control in adults. These medications could potentially be used with overweight adolescents. No weight-loss agents are currently approved by US FDA for children younger than 16 years. The aim of the present study was to increase weight loss in obese adolescents by combining a comprehensive behavioral program with pharmacotherapy. This study is the first randomized, placebo-controlled trial of sibutramine in the treatment of obese youth.

A randomized double-blind, placebo controlled trial consisting for 82 adolescents aged 13 to 17 years with a body mass index (BMI) of 32 to 44 was conducted from March 1999 to August 2000 at a university-based clinic for 6 months, followed by open-label treatment during months 7 to 12. For the first 6 months, participants received either behavior therapy (BT) and sibutramine or BT and placebo. For months 7 to 12, all participants received sibutramine in open-label treatment. Adolescents in both treatment conditions received the same comprehensive family-based behavioral weight-loss program delivered following detailed treatment manuals. In phase 1, participants attended 13 weekly group sessions followed up by 6 biweekly group sessions. In phase 2, group sessions were held biweekly from months 7 to 9 and monthly from months 10 to 12. Parents met separately in group sessions held on the same schedule as the adolescents' meetings. Groups were led by dietitians, psychologists, or psychiatrists.

Adolescents in both treatment groups were instructed to consume a 1200 to 1500 kcal/d diet of conventional foods, with approximately 30% of calories from fat, 15% from protein, and the remainder from carbohydrate. They were prescribed an eventual goal of walking or engaging in similar aerobic activity for 120 min per week or more. Participants kept daily eating and activity logs that they submitted at each session. The content of the parents' sessions paralleled that of their children's sessions.

At month 6 during phase I (placebo controlled), participants in the BT and sibutramine group lost a mean of 7.8 kg equal to an 8.5% reduction in initial BMI. In contrast, subjects treated with BT and placebo lost 3.2 kg, equal to a significantly smaller 4.0% reduction in BMI. More than twice as many adolescents in the BT and sibutramine group reduced their initial BMI by 10% and 15% compared with those treated by BT and placebo. In phase 2 (open label sibutramine treatment), participants who were originally treated with placebo and were switched to sibutramine from months 7 to 12 lost an additional 1.3 kg during this period, reducing their baseline BMI by an additional 2.4%. In contrast, participants originally treated with sibutramine who continued medication gained 0.8 kg during months 7 to 12. Significantly greater reductions in hunger were reported by participants who received BT and sibutramine. Medication dose was reduced (n=23) or discontinued (n=10) to manage increases in blood pressure, pulse rate, or other symptoms.

The addition of sibutramine to a comprehensive behavioral program induced significantly more weight loss than did BT and placebo. Until more extensive safety and efficacy data are available, medications for weight loss should be used only on an experimental basis in adolescents and children.

R Berkowitz, T Wadden, A Tershakovec, J Cronquist. Behavior therapy and Sibutramine for the treatment of adolescent obesity, JAMA 289(14): 1805-1812 (April 2003) [Correspondence: Robert I Berkowitz, MD, Weight and Eating Disorders Program, University of Pennsylvania, 3535 Market St, Suite 3026, Philadelphia, PA 19104-3309. e-mail: rberk@mail.med.upenn.edu]