This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
MASTER DAPT is a completed randomized parallel-group clinical trial in patients with high bleeding risk, coronary artery disease, and PCI. The registry describes management after bioresorbable polymer coated stent implantation with an abbreviated versus prolonged DAPT regimen and identifies three primary endpoints assessed at 11 months.
| Feature | MASTER DAPT |
|---|---|
| Study name | Management of High Bleeding Risk Patients Post Bioresorbable Polymer Coated Stent Implantation With an Abbreviated Versus Prolonged DAPT Regimen |
| NCT ID | NCT03023020 |
| Phase | NA |
| Status | COMPLETED |
| Allocation | RANDOMIZED |
| Design model | PARALLEL |
| Masking | NONE |
| Primary purpose | TREATMENT |
| Enrollment | 4579 |
| Number of arms | 2 |
| Lead sponsor | ECRI bv |
| Sponsor type | INDUSTRY |
| Conditions | High Bleeding Risk; Coronary Artery Disease; PCI |
2. Clinical Question
The clinical question is whether an abbreviated DAPT regimen differs from a prolonged DAPT regimen with respect to a composite of ischemic and bleeding outcomes in patients with high bleeding risk after bioresorbable polymer coated stent implantation.
Population
Patients with high bleeding risk, coronary artery disease, and PCI.
Interventions
Aspirin and a P2Y12 inhibitor are identified as the trial interventions in the registry.
Comparison
The study title specifies an abbreviated versus prolonged DAPT regimen after bioresorbable polymer coated stent implantation.
Primary question
How do the randomized DAPT strategies compare on NACE, MACCE, and major or clinically relevant non-major bleeding at 11 months?
3. Trial Design
The registry classifies MASTER DAPT as a randomized, parallel-group, unmasked treatment trial with two arms. The primary purpose is treatment. Enrollment was 4579 participants.
Abbreviated DAPT regimen
- Aspirin
- P2Y12 inhibitor
- Abbreviated DAPT strategy as specified by the study title
Prolonged DAPT regimen
- Aspirin
- P2Y12 inhibitor
- Prolonged DAPT strategy as specified by the study title
4. Trial Timeline
Study start
The registry lists 2017-04-04 as the study start date.
Primary completion
The registry lists 2021-04-30 as the primary completion date.
Registry status
The study status is recorded as COMPLETED.
5. Endpoints
MASTER DAPT has three registered primary endpoints. Each is assessed over an 11-month time frame.
| Primary endpoint | Registry definition | Time frame |
|---|---|---|
| Net adverse clinical endpoints (NACE) | Composite of all-cause death, myocardial infarction, stroke and bleeding events defined as BARC 3 or 5 | 11 months |
| Major adverse cardiac and cerebral events (MACCE) | Composite of all-cause death, myocardial infarction and stroke | 11 months |
| Major or clinically relevant non-major bleeding (MCB) | Composite of type 2, 3 and 5 BARC bleeding events | 11 months |
NACE
NACE is a composite endpoint that combines ischemic and bleeding components. Its components are all-cause death, myocardial infarction, stroke, and bleeding events defined as BARC 3 or 5.
MACCE
MACCE is a composite restricted to three clinical events: all-cause death, myocardial infarction, and stroke. It therefore represents the ischemic and mortality component of the broader NACE definition without the specified bleeding component.
MCB
MCB is a bleeding composite consisting of type 2, 3 and 5 BARC bleeding events. It is distinct from NACE because NACE includes death, myocardial infarction, stroke, and BARC 3 or 5 bleeding.
6. Statistical Methodology
The registry identifies three primary composite endpoints, all measured at 11 months, but the available registry record does not report posted statistical analyses or numerical endpoint results.
Time-to-event framework
For an endpoint evaluated over follow-up, a time-to-event analysis is commonly used when the timing of events and censoring are available. Kaplan-Meier methods can describe the estimated event-free probability over time, while a log-rank test can compare event-time distributions between randomized groups.
Here, T represents the time to the event of interest. The corresponding event-free probability can be evaluated over the prespecified follow-up period.
Hazard ratios
If the analysis uses a Cox proportional-hazards model, the hazard ratio summarizes the relative instantaneous event rate between randomized groups over the modeled follow-up. A hazard ratio below 1 would indicate a lower estimated hazard in the numerator group; a hazard ratio above 1 would indicate a higher estimated hazard.
The hazard ratio is not an absolute risk difference and does not directly state how many patients experience or avoid an event.
Fixed-time event comparison
Because each registered primary endpoint has an 11-month time frame, a complementary analysis can compare the proportion of participants experiencing the specified endpoint by that time point. The appropriate analysis depends on the prespecified statistical analysis plan, censoring rules, and how the registry defines the estimand.
Composite endpoint analysis
For a composite endpoint, the statistical analysis generally treats the first qualifying component event as the endpoint event when a time-to-first-event strategy is prespecified. Interpretation should then be supplemented by component-specific event counts because a treatment difference may be driven disproportionately by one component.
Randomization and causal comparison
Randomization is central to the treatment comparison because it creates the basis for comparing outcomes between the assigned strategies without relying on baseline prognostic adjustment to create treatment groups. The registry identifies MASTER DAPT as randomized and parallel-group.
7. Planned Analysis
The ClinicalTrials.gov record defines three primary outcomes to be evaluated at 11 months but does not post formal statistical analyses or numerical endpoint results. The appropriate analysis therefore centers on the prespecified endpoint definitions and the statistical framework normally used for these types of clinical outcomes.
NACE
A composite of all-cause death, myocardial infarction, stroke, and BARC 3 or 5 bleeding. A time-to-first-event approach can compare the event experience between randomized groups if timing and censoring information are available.
MACCE
A composite of all-cause death, myocardial infarction, and stroke. Time-to-event methods can compare the distribution of time to the first qualifying component.
MCB
A composite of BARC type 2, 3 and 5 bleeding. The analysis should preserve the distinction between bleeding-specific outcomes and the broader NACE composite.
11-month assessment
The registered time frame is 11 months for all three primary endpoints. Any formal estimate should follow the prespecified censoring and analysis rules.
8. Statistical Methods Explained
Why use a composite endpoint?
A composite combines multiple clinically relevant events into one outcome. This can increase the number of observed endpoint events and provide a broader measure of clinical outcomes, but interpretation depends on the importance, frequency, and treatment sensitivity of its individual components.
Why are NACE and MACCE different?
NACE includes all-cause death, myocardial infarction, stroke, and specified BARC 3 or 5 bleeding. MACCE includes all-cause death, myocardial infarction, and stroke. Thus, the definitions overlap but are not identical.
Why is MCB a separate primary endpoint?
MCB focuses specifically on bleeding, using BARC type 2, 3 and 5 events. Separating this endpoint from NACE allows the bleeding dimension of the DAPT comparison to be examined independently of the ischemic and mortality components.
Why does the 11-month time frame matter?
A prespecified time frame defines the period over which the registered primary endpoint is evaluated. It prevents an analysis from silently changing the target follow-up period after looking at the accumulated data.
What does a hazard ratio measure?
A hazard ratio compares estimated instantaneous event rates between two groups over time. It does not equal a ratio of cumulative risks at 11 months and does not directly describe the absolute number of events prevented or caused.
Why inspect the individual components of a composite?
A statistically different composite can arise because of one component while other components show little difference. Component-level reporting therefore helps determine what aspect of the clinical outcome is contributing to the overall composite.
9. Confidence Intervals and P-Values
No confidence intervals or p-values for the three primary endpoints are posted in the statistical-analysis fields represented here.
In a conventional inferential analysis, a confidence interval would quantify statistical uncertainty around an estimated treatment effect. For example, a confidence interval around a hazard ratio describes uncertainty in the estimated relative hazard under the chosen model and sampling framework.
A p-value addresses the compatibility of the observed data with a specified null hypothesis under the statistical model. It does not measure the magnitude of an effect, the probability that a treatment is effective, or the clinical importance of a finding.
For each primary endpoint, the most informative presentation would place the effect estimate, its confidence interval, and the corresponding hypothesis-test result together. The estimate describes the observed direction and magnitude; the confidence interval describes precision; and the p-value addresses the specified statistical test.
10. Non-Inferiority and Superiority Considerations
The study title describes an abbreviated versus prolonged DAPT regimen, but the registry information represented here does not specify a non-inferiority margin, superiority margin, or the formal hypothesis-testing hierarchy for the three primary endpoints.
These details matter because a non-inferiority analysis is not interpreted in the same way as an ordinary superiority test. A non-inferiority conclusion depends on whether the confidence interval for the treatment difference remains within a prespecified margin representing the largest clinically acceptable loss of efficacy.
The exact direction and scale depend on the chosen effect measure. The margin must be specified before interpreting the observed estimate.
11. Multiplicity
MASTER DAPT has three registered primary endpoints: NACE, MACCE, and MCB. When multiple primary endpoints are evaluated, the statistical interpretation depends on the prespecified multiplicity strategy.
| Endpoint | Clinical domain | Time frame | Multiplicity question |
|---|---|---|---|
| NACE | Composite ischemic, mortality, and bleeding outcome | 11 months | How the endpoint fits into the family of primary hypotheses |
| MACCE | Death, myocardial infarction, and stroke | 11 months | Whether it is tested jointly, sequentially, or under another prespecified strategy |
| MCB | Bleeding | 11 months | How type I error is controlled across the primary endpoint family |
Without the applicable statistical-analysis plan or posted results, the registry record alone does not establish the exact multiplicity adjustment or testing hierarchy for these three endpoints.
12. Censoring and Missing Data
Time-to-event analysis requires rules for participants who do not experience an endpoint during observed follow-up. Such participants may contribute information until the point at which their outcome status is no longer observed, after which they are censored according to the prespecified analysis rules.
The quality of a time-to-event estimate depends on the appropriateness of the censoring assumptions. If loss to follow-up is related to future event risk, simple non-informative censoring assumptions may be questionable.
Censoring
A participant without an observed endpoint by the end of available follow-up may contribute event-free follow-up up to the censoring time.
Missing outcome information
The statistical analysis plan should specify how incomplete outcome ascertainment is handled and which sensitivity analyses are appropriate.
13. Analysis Population
The registry identifies MASTER DAPT as randomized but does not provide posted analysis-population definitions for the primary endpoints in the information considered here.
For randomized treatment comparisons, an intention-to-treat analysis generally evaluates participants according to randomized assignment. Depending on the estimand and trial objective, additional per-protocol or as-treated analyses may be informative, particularly when treatment exposure differs between groups.
14. Safety and Bleeding Outcomes
Bleeding is directly incorporated into two of the three registered primary endpoint definitions. NACE includes bleeding events defined as BARC 3 or 5, while MCB includes BARC type 2, 3 and 5 bleeding events.
| Safety-related outcome | Definition in the registry |
|---|---|
| NACE bleeding component | BARC 3 or 5 bleeding events |
| MCB | Composite of type 2, 3 and 5 BARC bleeding events |
| Serious adverse events by arm | Not reported in the available registry data |
The distinction between BARC categories is important because the NACE and MCB definitions do not use the same bleeding threshold. Consequently, a result for MCB should not be substituted for the bleeding component of NACE.
15. Why Composite Endpoint Definitions Matter
The three primary endpoints create a useful statistical contrast. NACE combines mortality, ischemic events, and selected major bleeding. MACCE removes bleeding from that composite. MCB focuses on bleeding and includes BARC type 2 as well as types 3 and 5.
| Feature | NACE | MACCE | MCB |
|---|---|---|---|
| All-cause death | Yes | Yes | No |
| Myocardial infarction | Yes | Yes | No |
| Stroke | Yes | Yes | No |
| BARC 3 or 5 bleeding | Yes | No | Yes, as part of type 2, 3 and 5 |
| BARC type 2 bleeding | No | No | Yes |
This structure means that the same participant could contribute to different endpoint definitions depending on the event experienced. Statistical interpretation should therefore remain anchored to the precise registry definition rather than using the endpoint acronyms as interchangeable shorthand.
16. Statistical Interpretation of the Trial Design
Randomization provides the foundation for comparing the two DAPT strategies. It aims to balance measured and unmeasured prognostic factors in expectation, allowing differences in subsequent outcomes to be attributed to randomized treatment assignment under the trial's assumptions.
The registry classifies the study as having no masking. That design characteristic can matter particularly for outcomes whose ascertainment or management may be influenced by knowledge of treatment assignment. Objective event definitions and prespecified adjudication procedures can therefore be important components of endpoint integrity when available.
Each randomized participant belongs to one treatment strategy rather than sequentially receiving both strategies. The primary comparison therefore concerns outcomes between parallel randomized groups.
17. What a Formal Analysis Would Need to Establish
A complete statistical analysis of the three primary endpoints would need to specify more than the endpoint names and time frame. The statistical analysis plan would normally establish the estimand, analysis population, event definition, censoring rules, treatment-effect measure, hypothesis-testing framework, multiplicity procedure, and handling of missing information.
Estimand
Defines the treatment effect being targeted, including the population, treatment conditions, outcome, and relevant intercurrent events.
Effect measure
Could include a hazard ratio, risk difference, risk ratio, odds ratio, or another prespecified measure depending on the analysis.
Event handling
Composite definitions require explicit rules for identifying qualifying events and determining which event constitutes the endpoint event.
Error control
Three primary endpoints require a prespecified approach to the family of statistical hypotheses if formal confirmatory inference is intended.
18. Statistical Questions Raised by MASTER DAPT
- What is the primary estimand? The clinically relevant treatment effect must be defined before choosing the statistical estimator.
- How should competing clinical events be handled? Death, myocardial infarction, stroke, and bleeding can interact in ways that matter for time-to-event analyses.
- How should composite components be interpreted? The overall composite should be accompanied by component-level descriptions when available.
- How should multiple primary endpoints be handled? The confirmatory interpretation depends on the prespecified multiplicity strategy.
- What constitutes non-inferiority? If non-inferiority is an objective, the prespecified margin and direction of the effect measure determine the decision rule.
- How should missing follow-up be treated? Censoring and missing-data assumptions can affect estimated event probabilities and treatment comparisons.
19. Limitations
- No posted numerical endpoint results: the registry record considered here does not provide estimates, confidence intervals, or p-values for the three primary endpoints.
- No arm-specific enrollment counts: the total enrollment is 4579, but the available record does not provide the number randomized to each arm.
- No detailed regimen duration: the study title identifies abbreviated versus prolonged DAPT, while the intervention fields identify aspirin and a P2Y12 inhibitor without providing the arm-specific treatment durations.
- No posted statistical-analysis details: the available record does not establish the exact model, estimand, multiplicity procedure, or censoring rules used for the primary endpoints.
- Composite endpoints: NACE, MACCE, and MCB contain different event components and therefore answer different clinical questions.
- Unmasked design: the registry identifies the study as NONE for masking, which can be relevant to outcome ascertainment and management.
- Generalizability: the registry population is defined by high bleeding risk, coronary artery disease, and PCI, so applicability to populations outside those characteristics requires separate consideration.
20. Why This Trial Matters Statistically
MASTER DAPT provides a useful teaching example of how a randomized cardiovascular trial can frame several related but distinct statistical questions around ischemic outcomes, mortality, and bleeding.
| Concept | How it appears in MASTER DAPT |
|---|---|
| Randomization | The registry classifies the allocation as RANDOMIZED. |
| Parallel-group design | The design model is PARALLEL with 2 arms. |
| Unmasked treatment | The registry classifies masking as NONE. |
| Composite endpoint | NACE combines death, myocardial infarction, stroke, and specified bleeding. |
| Ischemic composite | MACCE combines death, myocardial infarction, and stroke. |
| Bleeding composite | MCB combines BARC type 2, 3 and 5 bleeding events. |
| Fixed follow-up | All three registered primary endpoints have an 11-month time frame. |
| Multiplicity | Three primary endpoints create a multiple-hypothesis testing question. |
| Non-inferiority logic | The abbreviated-versus-prolonged framing makes the prespecified margin and hypothesis framework important to interpretation if non-inferiority is part of the formal analysis. |
21. Record Summary
MASTER DAPT is a completed randomized parallel-group trial enrolling 4579 participants with high bleeding risk, coronary artery disease, and PCI. The registry describes a comparison of abbreviated versus prolonged DAPT after bioresorbable polymer coated stent implantation, with aspirin and a P2Y12 inhibitor identified as the trial interventions.
The three registered primary endpoints are NACE, MACCE, and MCB, all evaluated at 11 months. Their definitions deliberately separate a broad composite of mortality, ischemic events, and major bleeding from an ischemic composite and a bleeding-specific composite.
Statistically, the central issues are therefore not limited to a single treatment-effect estimate. They include the interpretation of composite endpoints, the choice of time-to-event versus fixed-time analysis, the role of censoring, the analysis population, the handling of multiple primary endpoints, and—if applicable to the formal hypothesis framework—the distinction between non-inferiority and superiority.
22. Sources
- ClinicalTrials.gov: NCT03023020 — MASTER DAPT.
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