Incidence of new onset type 2 diabetes in adults living with obesity treated with tirzepatide or semaglutide: real world evidence from an international retrospective cohort study.

Background: Tirzepatide, a novel dual agonist of glucagon-like-peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), has demonstrated greater magnitude of weight loss compared to semaglutide in a phase 3 clinical trial. However, the effect of tirzepatide on incidence of type 2 diabetes (T2D) in individuals with overweight and obesity, and the effect on major adverse cardiovascular outcomes in individuals with pre-existing T2D, remains unknown.

Methods: We performed a retrospective cohort study of anonymised electronic medical records using the TriNetX network (TriNetX LLC, Cambridge, MA, USA) a global federated database. The data used in this study was collected on 5th June 2024. Two cohorts of individuals were generated: 1) without pre-existing T2D and, 2) with T2D. We adopted an active comparator new user design on new initiations of either tirzepatide or semaglutide therapy. Analysis began from the index event which was defined as individuals on respective therapy for 6 months only. Analysis of outcomes was conducted off-drug, in individuals without a pre-existing history of the disease of interest. Individuals were followed up for 12 months post the index event. Primary outcome for cohort 1 was incidence of T2D, and for cohort 2 was composite: all-cause mortality, cerebral infarction, acute coronary syndrome, and heart failure. Secondary outcomes for cohort 1 were change in HbA1c and body weight and for cohort 2: incidence of micro- and macrovascular complications, suicidal ideation and/or attempt, and all-cause mortality. We propensity score matched (1:1) for potential confounders: baseline demographics, socioeconomic circumstances, HbA1c, weight, relevant co-morbidities, and anti-obesity, hypoglycaemic and cardioprotective agents.

Findings: The study population without T2D consisted of 13,846 individuals, equally split between tirzepatide and semaglutide users. Tirzepatide was associated with both lower risk for incident T2D (HR 0.73, 95% CI 0.58-0.92, p < 0.001) and greater weight loss (-7.7 kg, [95% CI -6.8, -8.5 kg], p < 0.001), compared to semaglutide (-4.8 kg, [95% CI -3.9, -5.6 kg], p < 0.001). In individuals with pre-existing T2D (n = 8446), tirzepatide was associated with lower risk of the composite outcome (HR 0.54, 95% CI 0.38-0.76, p < 0.001), cerebral infarction (HR 0.45, 95% CI 0.24-0.84, p = 0.010) and all-cause mortality (HR 0.33, 95% CI 0.15-0.73, p = 0.004) compared to semaglutide.

Interpretation: Tirzepatide is associated with significantly reduced risk of developing T2D and major adverse cardiovascular events in individuals living with obesity and T2D respectively. Randomised controlled trials investigating the utility of dual incretin agonists in the primary prevention of T2D and cardiovascular disease in higher risk populations are now required.

Funding: Nil.