Sympathomimetic increases resting energy expenditure following bariatric surgery: A randomized controlled clinical trial

Abstract

Objective: The aim of this study was to test the hypothesis that ephedrine + caffeine (EC) reduces the fall in resting energy expenditure (REE) following bariatric surgery.

Methods: This 32-week, randomized, double-blinded, placebo-controlled trial included 142 patients who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery. Participants were randomized to either EC or placebo for 27 weeks, beginning 5 weeks post surgery. The primary end points were change in REE (measured), percentage of predicted REE ([measured REE/Harris-Benedict equation-predicted REE] × 100), and body composition. Secondary outcomes included change in percentage of weight. Adverse events (AEs) were recorded.

Results: The reduction in REE was smaller in the EC versus the placebo group, but it was not significant. Percentage of predicted REE was increased in the EC versus the placebo group (difference, mean [SE]: 5.82 [2.29], p = 0.013). Percentage of weight (difference: -3.83 [1.39], p = 0.007) was reduced in the EC versus the placebo group. Percentage of predicted REE was increased and body weight decreased in the EC-treated participants who underwent SG compared with those who underwent SG and were treated with placebo (difference in percentage of predicted REE = 8.06 [2.83], p = 0.006; difference in weight percentage = -4.37 [1.92], p = 0.025). Percentage of fat-free mass was increased in the SG participants treated with EC versus placebo (difference: 1.31 [0.63], p = 0.042). The most common AEs were anxiety, dizziness, insomnia, and tremors. Most AEs were not different from placebo by Week 32.

Conclusions: EC enhances weight loss and reduces the fall in REE following bariatric surgery. Adrenergic symptoms mostly resolve over time.

Figure 1.

Consort diagram of enrollment and follow-up

Figure 2A and B.

Observed least squares mean (SE) percentage change from baseline in body weight at weeks 20 and 32 in (A) ephedrine and caffeine (EC) and placebo groups. *p = 0.007 compared with placebo. (B) patients treated with EC who underwent Roux-en-Y (RY-EC) and sleeve gastrectomy (SG-EC) surgery and their respective placebo groups (RY-PL and SG-PL). *p = 0.025, SG-EC compared with SG-PL.