Approved weight-loss medications have only modest effects on cardiovascular risk.
One rationale for the development and marketing of weight loss drugs is that their use will improve cardiac risk factors. In a recent systematic review and network meta-analysis  of 28 randomised controlled trials (29,018 participants), the authors concluded that the effects of weight loss drugs in improving cardiometabolic risk was modest at best. This pales into insignificance when compared with bariatric surgery for example that has been shown to improve cardiometabolic profile, and thus reduce the risk of adverse cardiovascular events .
A flaw in the report is that adverse events were not assessed; however, the authors reported that the trials had high drop-out rates, and noted that the trials did not last beyond 12 months.
The clinical effectiveness of any intervention in clinical practice should be based on the benefit-to-harm balance. We have previously shown that the use of centrally-acting weight loss drugs in particular significantly increase the risk of nervous, psychiatric, gastrointestinal adverse events ; this finding was no different when we compared withdrawn drugs to those presently on the marketed. While head-to-head comparisons of weight loss drugs provide insight into their potential comparative advantages, such comparisons should be assessed on the reporting of both benefit and harms.
Igho J. Onakpoya is a Physician and Research Fellow at the Centre for Evidence-Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford and Research editor BMJ Evidence-Based Medicine
Competing interests: None declared
Khera R, Pandey A, Chandar AK, Murad MH, Prokop LJ, Neeland IJ, Berry JD, Camilleri M, Singh S. Effects of Weight-Loss Medications on Cardiometabolic Risk Profiles: A Systematic Review and Network Meta-analysis. Gastroenterology. 2018 Apr;154(5):1309-1319.e7. doi: 10.1053/j.gastro.2017.12.024.