Metformin Cuts Obese Teens' Weight

By Michael Smith, North American Correspondent, MedPage Today Published: February 01, 2010 Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner Earn CME/CE credit for reading medical news

The diabetes drug metformin can help obese teenagers lose weight even if they don't have the disease, researchers said. In a randomized, placebo-controlled study that combined nearly two years of treatment and follow-up, the drug was associated with a statistically significant drop in body mass index, according to Darrell Wilson, MD, of Stanford University, and colleagues. But the drug appeared to have no effect on many other aspects of obesity, including fat distribution and insulin resistance, Wilson and colleagues reported in the February Archives of Pediatrics & Adolescent Medicine. The study is the longest and largest to test the effect of the drug, Wilson told MedPage Today. Treatment lasted 48 weeks, with another 48 weeks of follow-up, for 77 randomized volunteers. The researchers enrolled the teens (ages 13 to 17) at six pediatric centers in the U.S. After a one-month run-in, they were randomized to 2,000 milligrams of extended-release metformin or to a placebo. Action Points   Explain to interested patients that this study found that, for obese teens without diabetes, the diabetes drug metformin can help them lose weight. All participants also took part in a lifestyle modification program that included diet and exercise. To be eligible, the participants had to be in the 95th percentile or higher for their age and sex and could not have diabetes, Wilson said. The primary goal was to see if the drug had any effect on body mass index, but Wilson and colleagues also measured body fat using dual-emission X-ray absorptiometry and computer tomography (CT) scanning, and measured insulin resistance using an oral glucose tolerance test. After 48 weeks, they found, those in the metformin group had experienced on average a 0.9-point drop in body mass index, compared with a 0.2-point gain in the control group. The difference was significant at P=0.03. The weight loss is roughly equivalent to three kilograms (6.6 pounds) for a 5' 5" adolescent, Wilson and colleagues said. "It's not a 20-pound weight loss, it's not what the world is looking for in a weight-loss drug," he said. "It was a meaningful weight loss, just not a spectacular one." On the other hand, the researcher reported significant differences in body composition, abdominal fat, or insulin indices. The loss of weight lasted between 12 and 24 weeks after stopping the drug, the researchers reported. After that, the BMI of participants in the active group trended back toward levels of the placebo group. There were no significant differences between the groups in adverse events, which were mostly mild or moderate. Two cases of nausea in metformin-treated volunteers were considered probably related to the study drug. One participant stopped the drug because of the nausea. For clinicians, the study suggests that the drug might be useful in treating some obese adolescents, Wilson said. "We've certainly started some of our patients on it, but it has not unleashed us on a campaign of getting everybody on it," he said.