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The effect of antiobesity drugs on waist circumference: a mixed treatment comparison




To use meta-analytic techniques to quantitatively evaluate the efficacy of orlistat and lorcaserin in the treatment of people who are overweight and obese.


We identified publications from searches of electronic databases and extracted data from studies that compared orlistat or lorcaserin to lifestyle advice (standard care), placebo, sibutramine, rimonabant or metformin and collected information on waist circumference change or withdrawals due to adverse events (AEs). A mixed treatment comparison (MTC) meta-analysis was performed on the data extracted.


Orlistat was found to be significantly better than placebo and standard care in reducing waist circumference at 6 and 12 months; orlistat reduced waist circumference by −6.96 cm [95% credible interval (CrI): −8.93, −4.96 cm] compared to standard care at 6 months. The results suggested that lorcaserin reduced waist circumference by a greater amount than all other interventions at 12 months, for example, lorcaserin lead to a greater reduction of −2.45 cm (95% CrI: −4.99, 0.08 cm) in comparison to placebo, although these differences were not statistically significant. Although data were very limited, metformin reduced waist circumference by a greater amount (−2.11 cm, 95% CI: −1.00, −3.22 cm) than orlistat at 6 months. On average, 6.5% of patients on orlistat and 5.4% of those on lorcaserin discontinued their treatment due to AEs at 12 months.


Orlistat should be considered as an addition to lifestyle interventions in the treatment of obesity. Lorcaserin has recently been approved by the US Food and Drug Administration (FDA) and these results suggest that it is similar in both efficacy and safety compared to orlistat.