SURMOUNT-1: The Obesity Trial That Set a New Bar

SURMOUNT-1 (NEJM, 2022) enrolled 2,539 adults with obesity (mean BMI ~38) to tirzepatide 5/10/15 mg or placebo for 72 weeks. Mean weight reduction was 15.0%, 19.5%, and 20.9% respectively vs 3.1% placebo. Remarkably, 89–91% of those on 10–15 mg achieved ≥10% weight loss, and 36% of the 15 mg group achieved ≥25% — a magnitude previously associated only with bariatric surgery.

Weight loss was accompanied by improvements in waist circumference, blood pressure, lipids, and fasting insulin. This thread breaks down the estimands, the dose-response, and what the body-composition data showed.