To Help Obese, Study Compares 5 Weight-Loss Drugs

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To date, the FDA has approved five drugs to help people lose weight: orlistat, lorcaserin, naltrexone-buproprion, phentermine-topiramate, and liraglutide (brand names include Alli, Belviq, Contrave, Qsymia and Saxenda, respectively). While each drug has been individually studied and approved, how is one to know which might be most effective?

At the same time, healthcare providers need to understand which one, or ones, are most appropriate for their patients. A study just published in the Journal of the American Medical Association endeavors to clarify that issue.

Dr. Rohan Khera from the University of Iowa Carver College of Medicine in Iowa City, along with colleagues from several institutions, performed a meta-analysis of 28 randomized clinical trials involving over 29,000 individuals. Twenty-seven of the trials compared the efficacy of one of the above drugs in reducing body weight to the efficacy of a placebo. One trial compared two of them — liraglutide and orlistat — to each other and a placebo.

The studies chosen for the meta-analysis, besides being randomized, had to have followed their subjects for at least one year, and had to provide information on:

  • the number of participants who had lost at least 5 percent of their initial body weight
  • the number of participants who had lost at least 10 percent of their initial weight
  • the magnitude of weight loss
  • the discontinuation of drug use because of adverse events

Most of the participants (74 percent) were women, on average 46-years old. The median BMI was 36.1, putting them well into the obese category; their median initial body weight was about 100 kg (220 pounds).

For the main endpoint of losing 5 percent of initial body weight in one year, the drugs performed as noted below:

  • placebo: 23 percent of users lost 5 percent
  • phentermine-topiramte: 75 percent
  • liraglutide: 63 percent
  • naltrexone-bupropion: 55 percent
  • locaserin: 49 percent
  • orlistat: 44 percent

That was the good news — all the drugs succeeded in reaching the 5 percent weight-loss goal. But there also were some negative results because all were also associated with some degree of adverse events, with liraglutide and naltrexone-bupropion having the highest probability of negative treatment effects. In all the studies there were high attrition rates, on the order of 30 to 45 percent of participants dropping out of their respective studies.

Treatment choices, of course, must be individualized, as the authors noted:

"Besides weight loss, treatment decisions may also be driven by coexisting medical conditions, which may either favor or preclude the use of specific agents. For example, liraglutide may be a more appropriate agent in people with diabetes because of its glucose-lowering effects. Conversely, naltrexone-bupropion in patients with chronic opiate or alcohol dependence may be associated with neuropsychiatric complications."

While taking such factors into considerations, these data can serve as a useful guideline for healthcare providers working with obese individuals.