This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events (ACTIVE A) (NCT00249873), a randomized phase 3 study. The primary outcome is First Occurence of Any Component of the Composite of Stroke, Non-Central Nervous System (Non-CNS) Systemic Embolism, Myocardial Infarction or Vascular Death as Per Adjudication.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00249873 |
| Phase | Phase 3 |
| Condition | Atrial Fibrillation, Vascular Risk |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 7554 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sanofi |
| Results posted | Yes |
2. Clinical Question
Population
People with atrial fibrillation and at least one major vascular risk factor, including risk factors such as older age, increased blood pressure, a history of stroke or transient ischemic attack, or left ventricular dysfunction. The study also accepted people with atrial fibrillation who were unwilling to take oral anticoagulant therapy.
Intervention
Clopidogrel 75 mg once daily plus acetylsalicylic acid (ASA) 75 to 100 mg once daily, with the ASA dose at the investigators’ discretion.
Comparator
Matching placebo for clopidogrel plus ASA 75 to 100 mg once daily, with the ASA dose at the investigators’ discretion.
Primary question
Was assignment to clopidogrel plus ASA associated with a different time to the first occurrence of stroke, non-CNS systemic embolism, myocardial infarction, or vascular death than assignment to placebo plus ASA?
This is a question about the comparative occurrence of a composite outcome over follow-up, not about one isolated event type. The registry record describes the primary event as the first adjudicated occurrence of any component. Stroke and myocardial infarction include fatal and nonfatal events; systemic embolism is specified as non-CNS, and death is specified as vascular. A time-to-first-event question considers both whether a participant experiences an event and when the first event occurs.
The population definition matters to interpretation. The study concerns atrial fibrillation accompanied by vascular risk, and its summary also notes that people unwilling to take oral anticoagulant therapy could participate. The registry record does not report the proportions of participants with each listed risk factor or their reasons for not taking anticoagulant therapy. The findings therefore cannot be interpreted as applying equally to every clinical subgroup without subgroup results, which are not reported in the registry record.
3. Trial Design
ACTIVE A was a Phase 3, randomized, double-masked, parallel-group trial. The registry record reports enrollment of 7554 participants and a completed status. The listed study start is 2003-06 and the listed primary completion is 2009-03. The brief description anticipated a median follow-up of approximately 3 years; the actual median follow-up is not reported in the registry record.
Participants were assigned to clopidogrel plus ASA or matching placebo plus ASA. The clopidogrel dose was 75 mg once daily. The arm descriptions specify ASA 75 to 100 mg once daily, at investigators’ discretion; the brief summary describes 100 mg daily as the recommended dose. This dosing detail means the comparison is an add-on comparison of clopidogrel versus matching placebo in the presence of ASA, rather than a comparison of ASA with no antiplatelet treatment.
The official title also refers to factorial evaluation of irbesartan. However, the intervention and arm details in the registry record describe the clopidogrel-versus-placebo comparison, and the design details for an irbesartan component are not reported in the registry record. Its allocation, treatment groups, and results cannot be characterized from these details.
Randomization is intended to make treatment groups comparable at baseline on average, while masking is intended to reduce the influence of treatment knowledge on care and outcome assessment. These are general design principles, not evidence about how successfully the procedures were carried out in this trial. The method used to generate the allocation sequence, conceal allocation, maintain masking, or adjudicate outcomes beyond the stated adjudication is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Clopidogrel + ASA | Placebo + ASA |
|---|---|---|
| STARTED | 3772 | 3782 |
| COMPLETED | 2442 | 2528 |
| NOT COMPLETED | 1330 | 1254 |
Reasons for not completing this period:
| Reason | Clopidogrel + ASA | Placebo + ASA |
|---|---|---|
| Not treated | 7 | 8 |
| Significant thrombocytopenia | 9 | 8 |
| Severe allergic reaction | 8 | 1 |
| Serious haemorrhagic Adverse Event | 74 | 30 |
| Other Serious Adverse Event | 86 | 97 |
| Qualifying condition not present | 20 | 23 |
| Contraindication to oral anticoagulant | 4 | 8 |
| Withdrawal by Subject | 504 | 466 |
| Lost to Follow-up | 4 | 7 |
| Minor bleeding | 99 | 37 |
| Non-compliance | 41 | 46 |
| Other non serious Adverse Event | 112 | 108 |
Analysis population for the primary outcome, as defined in the registry: The intent-to-treat (ITT) population was used for all analyses. This consisted of all randomized patients irrespective of whether or not the patient actually received study drug or the patient's compliance with the study protocol. All patients were included in the treatment group to which they were originally allocated.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Clopidogrel + ASA | Placebo + ASA | Total |
|---|---|---|---|---|
| Participants analysed | 3772 | 3782 | 7554 | |
| Age, Customized: 18 to <65 years | participants | 931 | 935 | 1866 |
| Age, Customized: 65 to <75 years | participants | 1291 | 1258 | 2549 |
| Age, Customized: >= 75 years | participants | 1550 | 1589 | 3139 |
| Age, Continuous | years | 70.9 (SD 10.2) | 71.1 (SD 10.2) | 71.0 (SD 10.2) |
| Sex: Female, Male: Female | Participants | 1560 | 1597 | 3157 |
| Sex: Female, Male: Male | Participants | 2212 | 2185 | 4397 |
| CHADS2 Score: 0 | participants | 105 | 101 | 206 |
| CHADS2 Score: 1 | participants | 1360 | 1338 | 2698 |
| CHADS2 Score: 2 | participants | 1263 | 1315 | 2578 |
| CHADS2 Score: >2 | participants | 1040 | 1028 | 2068 |
| CHADS2 Score: Missing | participants | 4 | 0 | 4 |
| Sitting Systolic Blood Pressure: <120 mmHg | participants | 603 | 620 | 1223 |
| Sitting Systolic Blood Pressure: >=120 mmHg | participants | 3166 | 3159 | 6325 |
| Sitting Systolic Blood Pressure: Missing | participants | 3 | 3 | 6 |
| Body Mass Index (BMI) | kg/m² | 28.370 (SD 5.575) | 28.459 (SD 6.022) | 28.415 (SD 5.803) |
6. Primary Endpoint
The registry lists the primary outcome as First Occurence of Any Component of the Composite of Stroke, Non-Central Nervous System (Non-CNS) Systemic Embolism, Myocardial Infarction or Vascular Death as Per Adjudication, measured over expected median follow-up of approximately 3 years.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the first occurrence of any of four adjudicated outcomes during follow-up: stroke, non-CNS systemic embolism, myocardial infarction, or vascular death. Stroke and myocardial infarction may be fatal or nonfatal. The endpoint is expressed as a time-to-event outcome: the primary efficacy analysis is described as the time from randomization to the first primary event. The registry record also describes counts of participants with the composite event by arm, but numerical arm counts are not reported in the registry record.
A composite endpoint combines several events into one outcome. In general, this can capture a broader range of clinically important events and can provide more events for analysis than any one component alone. A time-to-first-event analysis focuses on the first qualifying event for each participant; later events do not replace the first event as the endpoint occurrence. That approach makes the timing of the initial event central to the comparison.
There is an interpretive trade-off. A composite result would describe the combined endpoint, not necessarily each component separately. Components can differ in frequency and clinical meaning, so an overall composite estimate cannot establish that the treatment effect is the same for stroke, embolism, myocardial infarction, and vascular death. Component-specific results are not reported in the registry record in the available trial details. The registry record does not report a numerical estimate for the primary endpoint, so the magnitude and precision of the treatment comparison cannot be assessed from the endpoint information alone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary endpoint and states that its efficacy analysis uses time from randomization to the first qualifying event. It does not report a numerical estimate of the treatment comparison, a confidence interval, or a p-value for that endpoint. It also does not provide numerical primary-event counts by arm in the trial details. As a result, the direction, magnitude, and statistical precision of the primary comparison cannot be determined from the registry record information available for this analysis.
The event definition combines stroke, non-CNS systemic embolism, myocardial infarction, and vascular death. Any eventual result for that composite would answer a question about the combined endpoint. It would not, by itself, show that each component moved in the same direction or by a similar amount. Component-specific estimates and their precision are not reported in the registry record. This is important because a composite can be influenced more strongly by components that occur more often, while less frequent components may contribute little information to the overall estimate.
A time-to-event comparison uses timing as well as event occurrence. General statistical explanation: participants who have not experienced the endpoint by the end of observed follow-up may contribute information up to that point, but interpretation depends on how follow-up and censoring are handled. The registry record does not report the censoring rules, losses to follow-up, or an observed follow-up distribution. The expected median follow-up of approximately 3 years is a description of expectation, not a reported observed median.
Enrollment of 7554 describes the trial size, not the number of participants who experienced the primary event and not the precision of an effect estimate. The registry record states that the intent-to-treat population was used for all analyses, including randomized participants irrespective of whether they received study drug or complied with the protocol. That analysis population helps define the comparison, but it cannot substitute for the missing outcome estimate.
The sample-size material is described as a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It is not the trial’s own design justification and should not be read as observed power. No numerical planning outputs or detected-effect fractions are reported in the registry record details. Without a primary estimate and its uncertainty, neither statistical significance nor clinical importance can be assessed. The posted information supports describing the question and design, but not a conclusion that either regimen performed better or worse on the primary outcome.
9. Statistical Methods Explained
The registry record describes a randomized, double-masked, parallel comparison and a primary efficacy analysis based on time from randomization to the first composite event. These features determine what the analysis is intended to compare. They do not reveal the actual treatment-effect estimate, the specific statistical model, or the results. Those details are not reported in the registry record.
What randomization contributes
General statistical explanation: randomization assigns treatment by chance, which is intended to balance both measured and unmeasured baseline characteristics across groups on average. This supports a causal comparison of assignment, provided the trial is conducted and analyzed appropriately. Randomization does not guarantee that groups will be identical in a particular trial, and it does not remove the need to report baseline characteristics, follow-up, adherence, and outcome results. The allocation-generation and concealment methods are not reported in the registry record.
The parallel design means each participant is assigned to one treatment group for the comparison, rather than crossing between the groups as part of the stated design. Double masking means the registry record labels the study as masked for two parties, but it does not identify those parties or describe procedures for preserving masking. The clopidogrel group received clopidogrel plus ASA, while the comparison group received matching placebo plus ASA. Thus, the treatment contrast is the addition of clopidogrel to an ASA regimen, with ASA dose at investigators’ discretion.
Why the primary analysis is time-to-event
General statistical explanation: a time-to-event analysis uses information about how long it takes for an event to occur, rather than reducing follow-up to a simple yes-or-no status at one common time. Participants may have different amounts of observed follow-up. Those who have not had an event by the end of their observed period can still contribute information up to that point, subject to the analysis’s assumptions and censoring rules. The registry record says the primary analysis uses time from randomization to the primary event, but does not identify the model, censoring rules, or assumptions used.
A time-to-event result is often expressed as a comparison of event rates over time, such as a hazard ratio, alongside an uncertainty interval. That is a general description of common reporting, not a claim about the method or result used in this trial. A hazard ratio, confidence interval, p-value, and analysis model are not reported in the registry record details. A count of participants with events, even if available, would not alone convey event timing or the full time-to-event estimate.
How to read the composite outcome
The endpoint counts the first occurrence of stroke, non-CNS systemic embolism, myocardial infarction, or vascular death, as adjudicated. General statistical explanation: an adjudication process applies defined criteria to decide whether a suspected event qualifies. Such processes can improve consistency, but the criteria, adjudication committee procedures, and blinding of adjudicators are not reported in the registry record. Because the endpoint is composite, a single treatment estimate would summarize the combined outcome. It would not prove that all components have equal effects or that any one component accounts for the result.
The registry record states that the intent-to-treat population was used for all analyses. In general, this means participants are analyzed according to their randomized treatment assignment, regardless of whether they received study drug or adhered to the protocol. This preserves the comparison created by randomization and estimates the effect of assignment under the trial’s conditions. It is distinct from an analysis limited to participants who followed treatment as planned. The record does not report supplementary per-protocol or as-treated analyses.
Multiplicity and uncertainty
Several outcomes and analyses can create multiplicity: when multiple statistical tests are conducted, the chance of at least one apparently unusual result can increase. General statistical explanation: an analysis plan may address this by prioritizing an endpoint, adjusting significance thresholds, or interpreting secondary outcomes as exploratory. The registry record lists one primary outcome and three secondary outcomes, but does not report a multiplicity adjustment, a hierarchy for testing, or whether secondary outcomes were confirmatory or exploratory. The primary outcome details also indicate that the result was not reduced to one comparison because it has several categories or time points. No specific single-comparison statistic can be inferred from that statement.
A confidence interval, in general, describes the range of effect values compatible with the data and the statistical method at a stated confidence level. Its width conveys precision: a wider interval indicates more uncertainty than a narrower interval. A p-value, in general, measures how unusual data at least as incompatible with a null hypothesis would be under that hypothesis and the model; it does not measure the probability that a treatment works. Neither a confidence interval nor a p-value for the primary treatment effect is reported in the registry record, so statistical precision and evidence against a null comparison cannot be assessed.
Planning calculations are not trial results
The registry record characterizes its sample-size assumptions as a planning illustration computed from the observed effect, not as the trial’s own design. The described assumptions include a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event calculations, the record describes total events, using the Schoenfeld approach; other calculations are described as participants per arm. No calculated planning values or effect fractions are reported in the registry record details. Such planning illustrations are not observed power and do not establish the probability that the trial detected an effect. The original sample-size justification and its assumptions are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies a primary outcome and lists three secondary outcomes: occurrence of stroke, death from any cause (cardiovascular and noncardiovascular), and adjudicated major bleedings. It also reports four outcome measures and four analyses. The primary endpoint is itself a composite, and the record notes that it has several categories or time points and was not reduced to one comparison in the analysis information summarized in the registry record.
When a study assesses several outcomes or makes repeated comparisons, multiplicity can increase the chance of a false-positive finding if each test is treated as an independent opportunity to declare a result. General statistical explanation: a prespecified testing hierarchy or adjustment can help control that issue, while clearly labeling secondary analyses as exploratory can guide interpretation. The registry record does not report whether any adjustment, hierarchy, or other multiplicity strategy was used. It is therefore not possible to determine how the reported analyses, if any, were protected against multiplicity.
The registry record states that all analyses used the intent-to-treat population: all randomized participants were included irrespective of study-drug receipt or protocol compliance, and participants remained in their assigned treatment group. This is the stated analysis-population approach. The actual number analyzed for each outcome, the handling of missing endpoint data, loss to follow-up, withdrawal, and censoring are not reported in the registry record. No imputation method or sensitivity analysis for missing data is described.
These omissions matter because analysis populations and missing-data procedures can affect what a treatment comparison estimates and how robust it is to incomplete observation. The stated intent-to-treat approach is informative, but it does not answer how incomplete outcome information was handled or whether other analysis sets were examined.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Clopidogrel + ASA | 1154 | 3772 | 30.6% |
| Placebo + ASA | 1069 | 3782 | 28.3% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Clopidogrel + ASA | 2542 of 3772 |
| Placebo + ASA | 2502 of 3782 |
Most frequent serious adverse event terms
| Event term | Organ system | Clopidogrel + ASA | Placebo + ASA |
|---|---|---|---|
| Pneumonia | Infections and infestations | 139 of 3772 | 128 of 3782 |
| Osteoarthritis | Musculoskeletal and connective tissue disorders | 28 of 3772 | 36 of 3782 |
| Chronic obstructive pulmonary disease | Respiratory, thoracic and mediastinal disorders | 28 of 3772 | 27 of 3782 |
| Urinary tract infection | Infections and infestations | 23 of 3772 | 28 of 3782 |
| Sepsis | Infections and infestations | 27 of 3772 | 19 of 3782 |
| Renal failure acute | Renal and urinary disorders | 22 of 3772 | 23 of 3782 |
| Fall | Injury, poisoning and procedural complications | 24 of 3772 | 19 of 3782 |
| Prostate cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 24 of 3772 | 16 of 3782 |
| Cataract | Eye disorders | 20 of 3772 | 18 of 3782 |
| Anaemia | Blood and lymphatic system disorders | 18 of 3772 | 19 of 3782 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Clopidogrel + ASA | Placebo + ASA |
|---|---|---|---|
| Any Infections and infestations | Infections and infestations | 994 of 3772 | 961 of 3782 |
| Any Gastrointestinal disorders | Gastrointestinal disorders | 806 of 3772 | 763 of 3782 |
| Any Nervous system disorders | Nervous system disorders | 661 of 3772 | 682 of 3782 |
| Any Musculoskeletal and connective tissue disorders | Musculoskeletal and connective tissue disorders | 532 of 3772 | 623 of 3782 |
| Any General disorders and administration site conditions | General disorders | 582 of 3772 | 541 of 3782 |
| Any Respiratory, thoracic and mediastinal disorders | Respiratory, thoracic and mediastinal disorders | 538 of 3772 | 510 of 3782 |
| Any Vascular disorders | Vascular disorders | 440 of 3772 | 414 of 3782 |
| Any Injury, poisoning and procedural complications | Injury, poisoning and procedural complications | 433 of 3772 | 353 of 3782 |
| Any Skin and subcutaneous tissue disorders | Skin and subcutaneous tissue disorders | 337 of 3772 | 289 of 3782 |
| Any Cardiac disorders | Cardiac disorders | 301 of 3772 | 314 of 3782 |
Serious events with the highest arm-level rate: pneumonia (3.7%), osteoarthritis (1.0%), upper gastrointestinal haemorrhage (0.7%), chronic obstructive pulmonary disease (0.7%), urinary tract infection (0.7%).
The registry record lists 3772 participants at risk in the Clopidogrel + ASA group and 3782 in the Placebo + ASA group. It lists 1154 serious adverse event affected participants and 1069 in the respective groups, and 2542 and 2502 affected participants for other adverse events. These are reported counts; they are not recalculated rates. The record does not provide the timing, duration, severity distribution, or event-level detail needed to interpret the counts fully. Death counts are not reported in the registry record.
The most frequent serious adverse event terms listed are pneumonia, 3.7%; osteoarthritis, 1.0%; upper gastrointestinal haemorrhage, 0.7%; chronic obstructive pulmonary disease, 0.7%; urinary tract infection, 0.7%; and sepsis, 0.7%. The registry record does not specify the denominator or arm-specific distribution for these percentages in the trial details. They should therefore be read as listed term frequencies, not as a treatment-group comparison or evidence that a treatment caused an event.
General statistical explanation: adverse-event counts and percentages describe events recorded during observation; they do not establish causation on their own. Interpretation depends on definitions, exposure time, ascertainment, baseline risk, and comparative analyses. The registry record does not provide enough detail on these elements to draw a comparative safety conclusion from the listed counts alone.
12. What the Result Does, and Does Not, Mean
The registry record establishes the clinical question and broad design: a randomized, double-masked, parallel comparison of clopidogrel plus ASA against matching placebo plus ASA in participants with atrial fibrillation and vascular risk. It defines the primary endpoint as time from randomization to the first adjudicated occurrence of a composite vascular event. It also states that analyses used the intent-to-treat population. These details explain what the trial was designed to compare and which participants were intended to be included in the analysis.
The available record details do not report a numerical primary treatment-effect estimate, confidence interval, or p-value. Therefore, they do not establish the direction or size of the primary comparison, how precisely it was estimated, or whether it met a statistical significance criterion. They also do not support a statement that clopidogrel plus ASA did or did not reduce the composite outcome. Such claims would require results not reported in the registry record.
Even if a numerical composite result were available, its scope would be the combined endpoint. It would not automatically establish a similar result for each component or for every subgroup in the study population. The registry record does not report component-specific effects or subgroup estimates in the trial details. The expected median follow-up of approximately 3 years also should not be treated as the observed follow-up duration; the observed median is not reported in the registry record.
General statistical explanation: an estimate and its confidence interval help distinguish the size of an observed difference from the uncertainty around it. Statistical significance, clinical importance, and causal interpretation are related but distinct questions. Enrollment alone cannot answer them. The result is also not equivalent to a comparison of clopidogrel against no background therapy, because both groups received ASA, with the dose selected within the stated range at investigators’ discretion.
The appropriate conclusion from the registry entries is limited: the trial was designed to evaluate an add-on clopidogrel comparison on an ASA background, using a time-to-first-event composite and an intent-to-treat analysis. The numerical efficacy and comparative safety conclusions are not reported in the registry record information.
13. Why This Trial Matters Statistically
This trial is statistically notable for combining a randomized, double-masked, parallel design with a time-to-event composite endpoint. Each feature shapes interpretation. Random assignment defines the treatment comparison, masking is intended to limit bias related to treatment knowledge, and the time-to-event endpoint incorporates when the first qualifying event occurs. The endpoint is not simply one disease event: it combines stroke, non-CNS systemic embolism, myocardial infarction, and vascular death.
Composite endpoints can be useful when several related outcomes are of interest, but their interpretation requires attention to the components. A combined result does not necessarily represent a consistent effect across all components. The endpoint’s first-event definition also differs from a count of all events over follow-up. Those distinctions are central to understanding what a trial estimate would mean, even when the primary estimate is not reported in the registry record.
The intent-to-treat population is another important statistical feature. Including randomized participants in their assigned groups, regardless of treatment receipt or compliance, retains the comparison based on assignment. It provides a different estimand from an analysis restricted to participants who adhered to treatment. However, the registry record does not describe missing-data handling, follow-up completeness, or additional analysis populations, so the robustness of the analysis cannot be evaluated from these details alone.
Finally, the record’s planning assumptions are explicitly described as an illustration rather than the trial’s design justification. This distinction helps prevent planning calculations from being mistaken for observed evidence or power. Enrollment of 7554 and an expected median follow-up of approximately 3 years describe the study’s scale and anticipated observation period, but neither substitutes for an effect estimate with uncertainty. The statistical question is clear; the numerical result needed to answer it is not reported in the registry record.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most important limitation of the registry entries is that they do not report the numerical primary treatment effect, its confidence interval, or its p-value. Primary-event counts by arm are also not reported in the trial details. Consequently, the direction, magnitude, and precision of the primary comparison cannot be evaluated. The record’s note that the primary outcome has several categories or time points and was not reduced to one comparison further limits a single-statistic interpretation.
The composite endpoint combines four event types. Without component-specific estimates, it is not possible to determine which components contributed most or whether the effect differed among them. The endpoint is described as adjudicated, but the criteria and adjudication procedures are not reported in the registry record. The registry record also does not report observed median follow-up, censoring rules, losses to follow-up, or how missing outcome information was handled.
ASA dosing was 75 to 100 mg once daily at investigators’ discretion, while the brief summary describes 100 mg daily as the recommended dose. The registry record does not report how participants were distributed across ASA doses or whether outcomes differed by dose. The official title refers to factorial evaluation of irbesartan, but the intervention and arm descriptions available for this comparison do not provide details of that component.
The record lists secondary outcomes and numbers of outcome measures and analyses, but a multiplicity strategy is not reported. It also does not report the trial’s own sample-size justification; the sample-size assumptions described are planning illustrations based on the observed effect. These limitations concern what can be interpreted from the registry record and do not establish that the underlying trial lacked such procedures or analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events (ACTIVE A) — NCT00249873.
- Registry record last updated 2015-06-15; status last verified 2015-05.
- Results first posted 2010-03-26.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
ACTIVE A is listed as a completed Phase 3 randomized, double-masked, parallel trial with enrollment of 7554. The listed study start is 2003-06 and primary completion is 2009-03. It compared clopidogrel 75 mg once daily plus ASA 75 to 100 mg once daily with matching placebo plus ASA in participants with atrial fibrillation and vascular risk. ASA dosing was at investigators’ discretion.
The primary endpoint was time from randomization to the first adjudicated occurrence of stroke, non-CNS systemic embolism, myocardial infarction, or vascular death. The registry record states that analyses used the intent-to-treat population. It lists secondary outcomes of stroke, death from any cause, and adjudicated major bleedings.
A numerical primary treatment effect, confidence interval, and p-value are not reported in the registry record details. Observed median follow-up, missing-data methods, multiplicity procedures, and the original sample-size justification are also not reported in the registry record.