• Meta-analysis of Weight Change in the Placebo Groups of Lorcaserin and Phentermine/Topiramate Trials from the FDA Database

      Slack, Marion; Korte, Andrew; Manley, Danielle; Parker, Nathan; Slack, Marion; College of Pharmacy, The University of Arizona (The University of Arizona., 2015)
      Objectives: To retrieve data from RCTs for lorcaserin and phentermine and topiramate combination on weight loss, BMI reduction, and other factors from the placebo groups and to determine if there is a difference in weight loss between those groups. Methods: Design: Meta-analysis Inclusion criteria: RCTs that compared lorcaserin or phentermine/topiramate to placebo as submitted to the FDA and posted to the FDA website. The studies needed to report weight loss or BMI values at baseline and post-treatment. Measures: The primary dependent variables were weight lost in kilograms, change in BMI, and percent who achieved 5% weight loss in the placebo arm. Data Collection: A standardized data collection form was used to extract data from the selected trials. Data was independently extracted by 3 researchers and discrepancies were resolved by consensus. Data Analysis: Data was analyzed by constructing a forest plot of the amount of weight lost in the placebo arm stratified by type of drug. A funnel plot and Kendall’s tau were used to assess publication bias. Heterogeneity was assessed with I2. The a priori alpha level was 0.05. Results: Statistically significant weight loss was achieved in the placebo arm in all 6 RCTs Weight loss was consistent across type of study Lorcaserin studies, mean = 2.42 kg Phentermine/topiramate studies, mean = 2.14 kg Overall rate of 5% weight loss was 0.32 No data was reported on actual caloric intake or actual quantity of exercise Funnel plot and Kendall’s tau (p = 0.85) indicated there was no publication bias There was heterogeneity in the lorcaserin studies resulting from one study reporting a large effect Conclusions: Participants in the placebo arm lost weight with monthly counseling on calorie intake and exercise, however, actual caloric intake or quantity of exercise that resulted in the weight loss is unknown.