Tirzepatide Lowers Heart Event Risk by 20% vs. Dulaglutide and Matches Semaglutide in 34,500 Real-World Patients

After propensity score matching: Tirzepatide vs. dulaglutide (9,233 pairs) — tirzepatide had lower modified MACE (IR 31.3 vs 39.4 per 1,000 person-years; HR 0.80, 95% CI 0.65-0.99), driven by 40% lower all-cause mortality (HR 0.60, 95% CI 0.43-0.83). Post hoc analysis showed lower pneumonia hospitalization with tirzepatide vs dulaglutide. Tirzepatide vs. semaglutide (25,266 pairs) — modified MACE rates were similar (IR 23.7 vs 23.2; HR 1.03, 95% CI 0.90-1.17).

Two target trial emulations using commercially insured US adults (June 2022-December 2024) with type 2 diabetes and established atherosclerotic cardiovascular disease. New initiators of tirzepatide were propensity score matched 1:1 with dulaglutide initiators (9,233 pairs) and separately with semaglutide initiators (25,266 pairs). Primary outcome was modified MACE (composite of non-fatal MI, non-fatal stroke, and all-cause death). Incidence rates and hazard ratios were estimated.

This is the largest real-world head-to-head comparison of tirzepatide against both dulaglutide and semaglutide for cardiovascular outcomes. It provides immediate clinical guidance: tirzepatide is clearly superior to dulaglutide for heart protection and equivalent to semaglutide. For patients currently on dulaglutide, switching to tirzepatide may reduce cardiovascular risk. For those choosing between tirzepatide and semaglutide, cardiovascular protection appears similar.

This study helps resolve a key clinical question as GLP-1 and dual-agonist prescribing surges. The finding that tirzepatide matches semaglutide's cardiovascular protection while offering superior metabolic benefits (weight loss, HbA1c reduction) strengthens the case for tirzepatide as a first-choice agent for patients with diabetes and heart disease. The mortality advantage over dulaglutide may accelerate switching from older GLP-1 agonists.

Observational target trial emulation — despite propensity score matching, unmeasured confounding cannot be excluded. The study used insurance claims data, which may have coding inaccuracies. The relatively short follow-up period (up to ~2.5 years) may not capture long-term differences. Tirzepatide initiators may differ from dulaglutide/semaglutide initiators in unmeasurable ways (e.g., provider enthusiasm, patient motivation). The pneumonia finding was post hoc and hypothesis-generating. Commercially insured patients may not represent Medicare or uninsured populations.