A comprehensive study found tirzepatide significantly outperformed semaglutide in promoting weight loss among adults with obesity or overweight conditions.

Over a median follow-up of 257 days, 81.8% of tirzepatide users achieved at least a 5% body weight loss, compared to 66.5% for semaglutide users, with further distinctions at higher weight loss thresholds.

The study, published in JAMA Internal Medicine, included 41,222 adults, with 18,386 undergoing detailed evaluation after propensity score matching. Statistical analysis involved chi-square tests for categorical data and independent t-tests for continuous variables. Multivariable logistic regression models adjusted for demographic factors and baseline body weight were used to further assess treatment outcomes.

The majority of participants were female (approximately 66%), and the average age was 52 years. Responses to treatment varied, particularly influenced by whether patients had type 2 diabetes (T2D). 

Subgroup analysis revealed that patients without diabetes experienced more substantial weight reductions than those with T2D, a trend consistent across both treatment groups. Specifically, participants without diabetes showed an average weight loss of 15.3% compared to 10.6% in patients with diabetes at the 12-month follow-up.

Tirzepatide led to greater weight loss across all subgroups and all evaluated time points. Data showed that at 6 months, patients on tirzepatide had a mean weight reduction of 12.5% (±2.1 SD) versus 7.8% (±2.0 SD) in the semaglutide group.

While specific financial details were not elaborated, preliminary analyses suggest tirzepatide may offer a favorable cost per kilogram of weight lost, particularly when accounting for reduced health care costs associated with improved weight management outcomes.

Investigators noted that further research is needed to assess long-term effectiveness and impacts on health care systems.