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., for the DAPA-MI Investigators

Bottom Line

In patients with acute myocardial infarction without prior diabetes or heart failure, dapagliflozin significantly improved a hierarchical composite of cardiometabolic outcomes but did not significantly reduce the incidence of cardiovascular death or heart failure hospitalization.

Key Findings

1. The primary hierarchical composite cardiometabolic outcome resulted in 32.9% wins for dapagliflozin and 24.6% wins for placebo, yielding a significant win ratio of 1.34 (95% CI, 1.20 to 1.50; P<0.001).
2. There was no significant difference between groups in the original composite outcome of cardiovascular death or hospitalization for heart failure, which occurred at a lower-than-expected rate of 2.5% in the dapagliflozin group versus 2.6% in the placebo group (HR 0.95; 95% CI, 0.64 to 1.40).
3. The overall benefit in the hierarchical win-ratio analysis was primarily driven by improvements in 'soft' cardiometabolic endpoints, including a lower incidence of new-onset type 2 diabetes (HR 0.53; 95% CI, 0.36 to 0.77), a higher frequency of body weight decrease ≥5%, and improvements in NYHA functional classification.

Study Design

Design
Registry-based RCT
Double-Blind
Sample
4,017
Patients
Duration
11.6 mo
Median
Setting
Sweden and UK
Population Hemodynamically stable patients presenting within 10 days of an acute myocardial infarction (STEMI or NSTEMI) with impaired left ventricular systolic function or Q-wave MI, and without known diabetes or chronic symptomatic heart failure.
Intervention Dapagliflozin 10 mg once daily added to standard of care.
Comparator Placebo once daily added to standard of care.
Outcome A hierarchical composite outcome assessed via the win ratio method: death, hospitalization for heart failure, nonfatal MI, atrial fibrillation/flutter, type 2 diabetes mellitus, NYHA functional classification at last visit, and body weight decrease ≥5% at last visit.

Study Limitations

The trial's primary endpoint was modified mid-study due to lower-than-anticipated hard clinical event rates, switching from a traditional time-to-event cardiovascular endpoint to a win-ratio analysis heavily influenced by weight loss and functional class.
The median follow-up of just 11.6 months was likely too short to capture meaningful differences in hard cardiovascular events, especially given the low baseline event rate in this optimally medically treated cohort.
The study excluded patients with known diabetes or established chronic heart failure, which limits generalizability to higher-risk acute MI populations (though these excluded groups already have established class I indications for SGLT2 inhibitors).
The low absolute number of cardiovascular events restricted statistical power for the evaluation of individual cardiovascular mortality and morbidity endpoints.

Clinical Significance

DAPA-MI demonstrated that initiating dapagliflozin shortly after an acute MI in patients without diabetes or prior heart failure yields significant cardiometabolic benefits, most notably preventing new-onset diabetes and promoting weight loss. However, its lack of effect on hard cardiovascular endpoints like death or heart failure hospitalization suggests that routine immediate post-MI use may not provide an incremental mortality benefit in this specific, low-risk, well-treated phenotype. A major achievement of the trial was methodological: it successfully proved the viability and efficiency of a pragmatic, registry-based randomized clinical trial (R-RCT) design, leveraging national databases (SWEDEHEART and MINAP) to streamline patient recruitment and follow-up.

Historical Context

Following the paradigm-shifting success of SGLT2 inhibitors in the management of established heart failure (e.g., DAPA-HF, EMPEROR-Reduced), chronic kidney disease, and type 2 diabetes, researchers hypothesized that initiating these agents early after an acute myocardial infarction could prevent incident heart failure and improve survival—much like the introduction of ACE inhibitors in the 1990s. DAPA-MI (along with the contemporaneous EMPACT-MI trial) tested this 'upstream' intervention strategy. However, because contemporary post-MI standard of care—including rapid revascularization, potent antiplatelets, high-intensity statins, and neurohormonal blockade—is highly effective, background cardiovascular event rates have plummeted. This trial highlights the modern challenge of proving incremental mortality or heart failure benefits in contemporary post-MI trials, prompting the adaptive shift to cardiometabolic endpoints.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What are the proposed physiological mechanisms by which an SGLT2 inhibitor like dapagliflozin might theoretically benefit a patient immediately post-myocardial infarction, even if they do not have baseline diabetes or heart failure?

Key Response

Students should understand that SGLT2 inhibitors have pleiotropic cardiovascular effects beyond glucose lowering. These include reducing preload through osmotic diuresis, decreasing afterload via improved endothelial function, shifting myocardial metabolism toward more efficient ketone bodies, and directly inhibiting Na+/H+ exchange in the myocardium to reduce intracellular calcium overload, all of which could theoretically mitigate adverse ventricular remodeling post-MI.

Resident
Resident

The DAPA-MI trial used a hierarchical composite outcome analyzed via the win ratio. Given that dapagliflozin improved this composite but did not significantly reduce cardiovascular death or heart failure hospitalizations, how should this influence your decision to prescribe it for a normoglycemic patient post-MI?

Key Response

Residents must recognize that the 'positive' primary outcome was driven by lower-priority metabolic endpoints such as weight loss and prevention of incident diabetes. Because it failed to reduce hard clinical outcomes like mortality or heart failure admissions in this specific population, it should not be routinely prescribed as a primary secondary-prevention cardiovascular drug post-MI in the absence of diabetes or established heart failure.

Fellow
Fellow

How do the results of the DAPA-MI trial contextualize the findings of the EMPACT-MI trial, and what do these data collectively suggest about the timing and efficacy of initiating SGLT2 inhibitors in the post-myocardial infarction setting?

Key Response

Fellows should synthesize recent literature: EMPACT-MI (empagliflozin post-MI with high risk for HF) similarly failed to show a significant reduction in its primary composite of all-cause mortality or HF hospitalization. Collectively, these trials demonstrate that routine initiation of SGLT2 inhibitors immediately post-MI in patients without established chronic heart failure does not yield the rapid, definitive cardiovascular benefits seen in trials of established HFrEF (like DAPA-HF), indicating a narrower therapeutic window for these agents.

Attending
Attending

When counseling a patient post-MI (without diabetes or heart failure) about the potential use of dapagliflozin based on DAPA-MI, how do you balance the proven 'soft' benefits against the lack of mortality benefit when engaging in shared decision-making regarding polypharmacy?

Key Response

Attendings must weigh pill burden, financial cost, and side effects against clinical utility. The teaching point is to transparently communicate that while the drug may prevent future diabetes and aid weight loss (metabolic benefits), it has not been proven to prolong life or prevent heart failure post-MI in their specific clinical scenario. This contrasts with proven mainstays like beta-blockers or statins, guiding a more individualized, patient-centered approach to prescribing.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The DAPA-MI trial utilized the win ratio method to evaluate a hierarchical composite endpoint. What are the statistical advantages of this approach, and what are the major methodological pitfalls when highly prevalent, continuous variables like a 5% weight loss are included in the hierarchy?

Key Response

The win ratio increases statistical power by evaluating a hierarchy of events, preventing less severe 'first events' from masking subsequent fatal events. However, the critical pitfall is that if high-tier hard events (like CV death) are rare, the overall win ratio becomes mathematically dominated by the lowest-tier, highly prevalent outcomes (like weight loss). This can yield a statistically significant 'win' that creates a misleading impression of broad clinical efficacy despite null effects on mortality.

Journal Editor
Journal Editor

From a critical editorial perspective, does the inclusion of non-cardiovascular endpoints like 'weight loss greater than 5%' and 'new onset diabetes' in a primary cardiometabolic win ratio for a cardiology trial threaten the validity of the study's conclusions, and how should a journal frame these findings to prevent misinterpretation?

Key Response

A seasoned reviewer would flag that combining traditional hard endpoints with metabolic surrogate markers in a single win ratio obscures the lack of direct cardiovascular benefit. Editorially, it is crucial to ensure the title, abstract, and conclusion explicitly clarify that the 'positive' primary outcome was driven entirely by metabolic factors, preventing readers and clinicians from misinterpreting the drug as life-saving or cardioprotective in this specific cohort.

Guideline Committee
Guideline Committee

Based on the findings of DAPA-MI, should current ACC/AHA guidelines for the management of acute myocardial infarction be updated to recommend SGLT2 inhibitors for patients regardless of left ventricular ejection fraction or diabetes status?

Key Response

Current ACC/AHA and ESC guidelines strongly recommend SGLT2 inhibitors for patients with established HFrEF or type 2 diabetes. Given the lack of benefit on CV death or HF hospitalization in DAPA-MI, the committee would conclude there is insufficient evidence (Level of Evidence B-R) to expand a Class I or IIa recommendation for routine SGLT2 inhibitor use in post-MI patients without these comorbidities, reinforcing the current practice of reserving these agents for those with established HF or DM.

Clinical Landscape

Noteworthy Related Trials

2015

EMPA-REG OUTCOME Trial

n = 7,020 · NEJM

Tested

Empagliflozin 10 mg or 25 mg daily

Population

Patients with type 2 diabetes and established cardiovascular disease

Comparator

Placebo

Endpoint

3-point MACE (cardiovascular death, nonfatal MI, or nonfatal stroke)

Key result: Empagliflozin significantly reduced the risk of the primary composite cardiovascular outcome and death from any cause.
2019

DAPA-HF Trial

n = 4,744 · NEJM

Tested

Dapagliflozin 10 mg daily

Population

Patients with heart failure and reduced ejection fraction, with or without type 2 diabetes

Comparator

Placebo

Endpoint

Composite of worsening heart failure or cardiovascular death

Key result: Dapagliflozin significantly reduced the risk of worsening heart failure or cardiovascular death compared to placebo, regardless of diabetes status.
2024

EMPACT-MI Trial

n = 6,522 · NEJM

Tested

Empagliflozin 10 mg daily

Population

Patients hospitalized for acute MI with a high risk of heart failure

Comparator

Placebo

Endpoint

Composite of first hospitalization for heart failure or death from any cause

Key result: Empagliflozin did not significantly lower the risk of the primary composite outcome of heart failure hospitalization or death from any cause compared to placebo.

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