SAN FRANCISCO — Medications for weight loss are little help as monotherapy, and it's questionable whether the benefits outweigh the risks, Dr. Robert Baron said at a diabetes update sponsored by the University of California, San Francisco.
Approved weight-loss medications such as sibutramine or orlistat produce an average 5% drop in weight beyond the weight loss achieved on placebo when used alone. Dieting alone leads to an average 8% weight loss beyond that achieved with placebo. The efficacy of drug and diet therapies are about the same, but medications carry potential side effects and cost more, said Dr. Baron, professor of medicine at the university.
He has no association with companies that make the drugs he discussed. His practice includes a small bariatric practice, but he chooses not to prescribe medications for weight loss.
There are no data to show that weight loss from medical therapy improves mortality. Trial end points are based on weight changes alone. Improving an intermediate end point such as weight doesn't necessarily reflect beneficial changes in mortality, “so be cautious with the use of drugs” for weight loss, he advised.
In the clinical trials that led to approval of some drugs for weight loss, the drugs were studied in combination with lifestyle modifications. The combination generally induces greater weight loss, and is the only way in which these medications should be used, he said.
National Institutes of Health guidelines recommend that drug therapy for weight loss may be considered in patients with a body mass index (BMI) of at least 30 kg/m2 or in patients with a BMI of 27 kg/m2 plus comorbidity. In this framework, nearly every patient with type II diabetes would qualify for a weight-loss medication, but in practice few should use one, he believes.
Dr. Baron advised against prescribing weight-loss medications during the patient's first visit. Instead, he suggested, start motivated patients on the same strategy used in clinical trials for these medications by beginning with a run-in period of lifestyle modifications with a low-calorie diet, structured exercise, and behavioral therapy. After 1 month, only those who are adherent and who are losing weight should qualify for consideration for a weight-loss medication.
If you choose to use a weight-loss drug, prescribe no more than 1 months' worth initially. “The data are very clear that the outcome at 1 month correlates very well to the outcome at 12 months. If the patient hasn't lost weight at 1 month, you can stop the drug with impunity,” he said. Counsel the patient about this strategy before beginning drug therapy.
Some medications used for other purposes can have weight-loss benefits. The most clinically useful of these is the antidepressant bupropion. In a randomized trial involving 327 obese patients, 5% of those on bupropion 300–400 mg lost modest amounts of weight, compared with 2% of those on placebo. “I would never prescribe this as a weight-loss drug,” but for overweight or obese patients who are depressed, “I now use bupropion as my drug of first choice.”
Dr. Baron cautioned against advertisements claiming that one drug is more effective than another based on the weight lost from baseline. Weight loss should be compared with the weight loss on placebo, he emphasized.