Medications for obesity

In his article on the use of medication in the management of obesity, Dr Sharma states that “there is now abundant evidence from pharmacologic trials that drugs such as orlistat, sibutramine, and rimonabant (a newer compound), when added to lifestyle interventions, can help patients maintain clinically meaningful weight loss for more than 2 years.”1 There are no citations given for this conclusion. The unstated implication is that these drugs can help achieve clinically meaningful results in terms of morbidity and mortality.

One of us searched the Cochrane Library for reviews about the effects of medication on weight-loss maintenance. There was 1 general review about the use of medication2 and 1 for each of the 3 drugs that Dr Sharma mentions.3–5 None of these 4 reviews provide any evidence that the use of these medications results in clinically meaningful patient outcomes, including noticeable average weight loss. The general review examined orlistat and sibutramine. In pharmacotherapeutic trials, of all the participants who withdrew from therapy during the weight-loss phase of the study, 33% were taking orlistat and 43% were taking sibutramine. These people were not followed up with and their outcomes were not reported at the end of the trial period, even though it is a common and ethical practice to follow-up with trial participants and obtain information on key outcomes despite early discontinuation of treatment. As a result, their weight gain or loss was not included in the efficacy estimates. This degree of incomplete reporting negates any scientific conclusions drawn from these studies. The authors of the review concluded that longer and more methodologically rigorous trials were required to fully evaluate any potential benefit of these weight-loss drugs.2

In one of the other studies, the rimonabant group had a similar attrition rate of approximately 40% of participants at the end of 1 year.5 The authors cautioned that results regarding weight loss needed to be viewed tentatively owing to the methodologic limitations of the trials. Their conclusion was that “studies with longer follow-ups after the end of treatment and of more rigorous quality should be done before definitive recommendations can be made regarding the role of this new medication in the management of overweight or obese patients.”

Beyond the issue of the role, if any, of these medications in the management of obesity, this also raises questions about the editorial process at Canadian Family Physician. Editors must ensure that strong claims are not published unless there is supporting evidence. In particular, editors should prevent publication of assertions that claims are supported by evidence when they are not.

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