MedicalResearch.com Interview with:
Christian Hampp PhD
Division of Epidemiology-I, Office of Pharmacovigilance and Epidemiology
Office of Surveillance and Epidemiology
Center for Drug Evaluation and Research
U.S. Food and Drug Administration
Silver Spring, Maryland
MedicalResearch.com: What are the main findings of the study?
Dr. Hampp: We investigated the use of prescription antiobesity drugs, including duration of use, in the United States from 2002 through 2011. We found that in 2011, approximately 2.74 million patients used antiobesity drugs, predominantly phentermine (2.43 million patients), while the use of prescription orlistat and sibutramine was relatively uncommon. Eighty-five percent of antiobesity drug users were female, 62% were aged 17-44 years, and 4.5% had a body mass index of ≤24.9 kg/m2. Duration of use was generally short and most patients only had one episode of antiobesity drug use during the observation period. The longest episode of use was ≤30 days in 47- 58% of patients. Approximately one quarter of patients used antiobesity drugs for longer than 90 days. Only 1.3- 4.2% of antiobesity drug users used them for >1 year.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Hampp: Some antiobesity drugs, including phentermine, are indicated for short-term use only, which is typically understood as less than 12 weeks. Other drugs, such as orlistat or sibutramine, before it was withdrawn in 2010, are not restricted with regard to duration of use. Nevertheless, we found little difference in duration of use among these drugs, regardless of their indicated duration of use. In fact, a quarter of phentermine patients exceeded 90 days of use. However, although we found longer durations of use in a portion of patients, we also saw that the majority of patients used weight-loss drugs for no more than one month. This proportion was similar for users of drugs indicated for short-term use or for long-term use. Whether the relatively early discontinuation is caused by perceived lack of effectiveness, the experience of unpleasant side effects, or other reasons is not known.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Hampp: Most patients will discontinue their weight-loss therapy very early. Although our study could not provide reasons for early discontinuation, it is important that physicians and patients discuss expectations to a weight-loss program based in whole or in part on prescription drugs.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Hampp: Future research should investigate reasons for early discontinuation and also measure the real-life benefits in terms of achieved weight loss considering actual duration of therapy.
Division of Epidemiology-I, Office of Pharmacovigilance and Epidemiology, Office of Surveillance and Epidemiology, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland.
Pharmacotherapy. 2013 Sep 9. doi: 10.1002/phar.1342. [Epub ahead of print]