NEJM Evidence NOVEMBER 11, 2023

Dapagliflozin in Myocardial Infarction Without Diabetes or Heart Failure (DAPA-MI)

Stefan James, David Erlinge, Robert F. Storey, et al.

Bottom Line

The DAPA-MI trial demonstrated that, in patients without diabetes or chronic heart failure following an acute myocardial infarction, dapagliflozin significantly improved a hierarchical composite of cardiometabolic outcomes compared to placebo, largely driven by reduced new-onset diabetes and weight loss, though with no difference in cardiovascular death or heart failure hospitalizations.

Key Findings

1. Dapagliflozin therapy resulted in a significantly higher likelihood of better cardiometabolic outcomes compared to placebo, with a win ratio of 1.34 (95% CI 1.20–1.50, p < 0.001).
2. The intervention demonstrated a significant reduction in the incidence of new-onset type 2 diabetes, with a hazard ratio of 0.53 (95% CI 0.36–0.77).
3. Patients in the dapagliflozin group experienced a greater mean body weight reduction of 1.65 kg (95% CI -2.12 to -1.18) compared to placebo.
4. There was no statistically significant difference in the original primary composite of cardiovascular death or hospitalization for heart failure (2.5% in the dapagliflozin group vs. 2.6% in the placebo group).
5. Major adverse cardiovascular events, including recurrent myocardial infarction and stroke, showed no significant difference between the study arms.

Study Design

Design
RCT
Double-Blind
Sample
4,017
Patients
Duration
12 mo
Median
Setting
Multicenter, Europe
Population Patients with acute myocardial infarction (STEMI or NSTEMI) and impaired left ventricular systolic function or Q-wave MI, without a history of type 1 or 2 diabetes or chronic heart failure.
Intervention Dapagliflozin 10 mg daily
Comparator Placebo
Outcome Hierarchical composite of death, hospitalization for heart failure, nonfatal myocardial infarction, atrial fibrillation/flutter, type 2 diabetes, NYHA functional class at the last visit, and a body weight decrease of 5% or greater at the last visit.

Study Limitations

The primary endpoint was modified to a hierarchical composite of cardiometabolic outcomes post-enrollment because event rates for the original primary outcome of cardiovascular death and heart failure hospitalization were lower than anticipated.
The hierarchical 'win ratio' analysis is a complex statistical method that can be challenging to interpret in the context of traditional 'hard' cardiovascular endpoints.
The study population consisted of relatively low-risk patients, which may limit the generalizability of these findings to higher-risk cohorts.
The trial was conducted primarily using registry-based infrastructure, which, while efficient, may lack the granularity of traditional site-managed data collection.

Clinical Significance

The trial suggests that initiating dapagliflozin shortly after an acute MI in patients without diabetes may offer cardiometabolic benefits, such as preventing new-onset diabetes and promoting weight loss, which are favorable in a secondary prevention context. However, it does not support the routine use of dapagliflozin in this specific population for the sole purpose of reducing cardiovascular mortality or heart failure hospitalizations.

Historical Context

Sodium-glucose cotransporter-2 (SGLT2) inhibitors established themselves as transformative therapies for heart failure and chronic kidney disease in patients with and without diabetes. DAPA-MI sought to extend this therapeutic evidence base to the acute myocardial infarction setting, shifting focus toward early intervention in a lower-risk population to see if metabolic gains could translate to long-term cardiovascular stability.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What is the primary physiological mechanism of sodium-glucose cotransporter 2 (SGLT2) inhibitors that extends their utility to patients without diabetes, particularly in the post-myocardial infarction setting?

Key Response

SGLT2 inhibitors promote natriuresis and osmotic diuresis, which reduces preload and afterload. Beyond glucose lowering, they shift myocardial metabolism toward more efficient ketone body oxidation, reduce oxidative stress, and decrease sympathetic activity, all of which support favorable left ventricular remodeling and decrease the risk of heart failure even in euglycemic patients.

Resident
Resident

In a patient who has just suffered an acute MI but has no history of diabetes or heart failure (LVEF > 40%), what specific benefits does the DAPA-MI trial suggest for initiating dapagliflozin prior to discharge?

Key Response

DAPA-MI showed that dapagliflozin significantly improved a hierarchical composite outcome (win ratio) primarily driven by cardiometabolic benefits, including weight loss and a reduction in new-onset diabetes. However, unlike trials in patients with established heart failure or diabetes, it did not significantly reduce the individual risks of cardiovascular death or heart failure hospitalization in this specific low-risk population.

Fellow
Fellow

The DAPA-MI trial utilized a 'win ratio' approach for its primary endpoint. How does the inclusion of 'softer' endpoints like weight loss and new-onset diabetes in this hierarchical model complicate the interpretation of dapagliflozin's efficacy in preventing major adverse cardiovascular events (MACE) post-MI?

Key Response

The win ratio prioritizes hard outcomes (death, HFH) but allows the trial to gain power from more frequent outcomes (weight change, HbA1c). In DAPA-MI, the 'win' was almost entirely due to metabolic parameters. For a fellow, this necessitates a nuanced discussion with patients: the drug is a potent cardiometabolic stabilizer, but the trial was likely underpowered or the population too low-risk to demonstrate the mortality/morbidity benefits seen in the DAPA-HF or EMPA-KIDNEY cohorts.

Attending
Attending

Given the results of DAPA-MI and the concurrent EMPACT-MI trial, how should we balance the 'early and often' philosophy of SGLT2i initiation against the lack of significant reduction in hard cardiovascular endpoints in the acute post-MI period for patients without baseline HF or DM?

Key Response

The DAPA-MI trial suggests that while safe and metabolically beneficial, the immediate post-MI initiation of SGLT2i in patients without HF or DM does not carry the same 'life-saving' urgency as it does in HFrEF. Practitioners should view SGLT2i in this cohort as a strategy for long-term metabolic health and primary prevention of diabetes rather than an acute intervention for reducing 12-month CV mortality.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

Critique the use of a hierarchical win ratio in DAPA-MI from a statistical power perspective. What are the implications of the 'win' being driven by the lowest tier of the hierarchy (weight loss/diabetes) when the higher-tier components (CV death) showed no significant difference?

Key Response

The win ratio can be sensitive to the ordering and the frequency of events. Since weight loss and HbA1c changes occur in nearly every participant, they dominate the win ratio calculation once the rare occurrences of death or HFH are accounted for. This can result in a statistically significant 'win' that may not reflect a clinically meaningful shift in the primary disease process (infarction-induced HF), necessitating sensitivity analyses that exclude the 'soft' tiers to confirm robustness.

Journal Editor
Journal Editor

DAPA-MI moved from a traditional MACE endpoint to a hierarchical composite win ratio during the course of the study. As a reviewer, what concerns would you raise regarding 'mid-stream' changes to primary endpoints and the potential for 'p-hacking' or result optimization?

Key Response

Changing a primary endpoint after the start of a trial (even if blinded) often triggers concerns about statistical opportunistic behavior. An editor would demand rigorous proof that the change was made without knowledge of the accumulating data and would likely flag the discrepancy between the 'positive' composite and the 'negative' components of CV death and HFH, questioning if the trial's 'positive' label is somewhat misleading regarding hard clinical outcomes.

Guideline Committee
Guideline Committee

Should current ACS guidelines (e.g., ACC/AHA or ESC) be updated to include a Class I recommendation for SGLT2 inhibitors in all post-MI patients regardless of LVEF or glycemic status, or does DAPA-MI support a more conservative Class IIb recommendation?

Key Response

Current guidelines (like the 2023 ESC Guidelines for ACS) strongly recommend SGLT2i for patients with DM or HFrEF (Class I). DAPA-MI provides evidence for cardiometabolic benefit but fails to show a reduction in CV death or HFH in those without these conditions. Therefore, a Class I recommendation is unlikely; a Class IIa or IIb recommendation for 'reduction of cardiometabolic risk' is more appropriate, emphasizing that the benefit is primarily metabolic rather than a reduction in immediate post-ischemic structural failure.

Clinical Landscape

Noteworthy Related Trials

2015

EMPA-REG OUTCOME

n = 7,020 · NEJM

Tested

Empagliflozin 10/25mg daily

Population

T2DM patients with high cardiovascular risk

Comparator

Placebo

Endpoint

3-point MACE

Key result: Empagliflozin reduced the risk of cardiovascular death and hospitalization for heart failure in high-risk diabetic patients.
2019

DAPA-HF Trial

n = 4,744 · NEJM

Tested

Dapagliflozin 10mg daily

Population

Patients with HFrEF

Comparator

Placebo

Endpoint

Composite of worsening heart failure or cardiovascular death

Key result: Dapagliflozin significantly reduced the risk of worsening heart failure and cardiovascular death in patients with HFrEF.
2021

EMMI Trial

n = 515 · JACC

Tested

Empagliflozin 10mg daily

Population

Patients with acute myocardial infarction

Comparator

Placebo

Endpoint

Change in left ventricular end-systolic volume index

Key result: Empagliflozin did not significantly improve left ventricular remodeling after acute MI compared to placebo.

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