In the SURMOUNT-4 trial, 82.5% of adults with obesity regained ≥25% of initial weight lost within one year of tirzepatide withdrawal; most showed reversal of cardiometabolic improvements.
This post hoc analysis was performed on the modified intent-to-treat population, comprising all randomly assigned participants who were exposed to at least 1 dose of the study drug. The analysis only included tirzepatide-treated participants randomized to placebo who achieved 10% or more weight reduction at week 36 with the maximum tolerated dose of tirzepatide. The 10% cutoff was chosen to build an analysis population of clinically meaningful weight reduction. Most participants met this cutoff (308 of 335 participants). Only participants with a nonmissing week 36 weight measurement value and at least 1 nonmissing weight measurement value after week 36 were included in the analysis.
For the calculation of percentage of weight regain from week 36 to week 88 relative to week 36, missing weight measures at week 88 were imputed by predictions using observed data through a mixed model for repeated measures adjusted for week 0 value, week 36 value, country, sex, and maximum tolerated dose of tirzepatide at week 36. All outcomes were evaluated within each category of weight regain.
Baseline demographic and clinical characteristics (at week 0) and changes from week 0 to week 36 in clinical characteristics were assessed using descriptive summary statistics. Continuous variables were presented as means and SDs and categorical variables were presented as counts and percentages. P values for comparison among categories of weight regain from week 36 to week 88 were computed using analysis of variance in continuous data and χ2 test in categorical data.
