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Weighing up the evidence: a meta-analysis and therapeutic audit of the treatments for obesity

Josh Lawley

University of Leeds, Leeds LS2 9JT, UK


25 Jan 2014


4 Jun 2014


2 Jul 2014






obesity, diet, bariatric, meta-analysis, orlistat, lorcaserin


There is an urgent need to find the most cost-effective treatment to help manage the ‘epidemic of obesity’. This study examined the long-term efficacy of lifestyle, pharmaceutical and surgical interventions of reducing weight in obese patients by carrying out a meta-analysis of published studies. English language randomized controlled trials were identified from Pubmed and the Cochrane Library in March 2013 that examined interventions for a minimum of 1 year in adults aged 18–70 years. Trials were selected on the basis of a Jadad score of >2 for pharmaceutical interventions and >1 for surgical interventions. Exercise and diet-combined therapy was more effective in producing weight loss than diet alone (mean of 5.18 ± 3.37 kg vs. 3.54 ± 3.67 kg), with a mean difference of 1.26 kg with 95% confidence interval (CI): 0.35–2.17 kg). Bariatric surgery resulted in a mean of 16.82% more body weight lost compared with a control group (95% CI: 14.60–19.03%). With respect to drug therapies, patients treated with lorcaserin lost a mean of 3.23 kg (95% CI: 2.70 to 3.75 kg) more than placebo (or 3.00% at 95% CI: 3.41–2.59). In contrast, patients treated with orlistat only lost a mean of 2.85 kg more than placebo (95% CI: 2.49–3.20 kg), equivalent to 2.88% (95% CI: 2.43–3.33%). These results indicate that bariatric surgery is the most effective intervention at causing clinically significant long-term weight loss, for patients with a body mass index of >35 kg/m2. However, it is also associated with considerable risks. Further research is also needed to identify whether lorcaserin or orlistat have a greater effect in particular patient sub-groups and examine the long-term efficacy of other drugs currently used off label for weight loss.

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