XIENCE 28 Global Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for XIENCE 28 Global Study (NCT03355742), a na na study. The primary outcome is Number of Participants With Composite of Net Adverse Clinical Endpoint (NACE), by Propensity Score Quintiles.

2. Clinical Question

3. Trial Design

XIENCE 28 Global Study was a prospective, multi-center, open-label, non-randomized, single-group study. It evaluated a 1-month course of dual antiplatelet therapy (DAPT), as short as 28 days, following PCI with an approved XIENCE family coronary drug-eluting stent in participants at high risk of bleeding. The registry lists XIENCE with short-duration DAPT as the study arm.

The enrollment was 963. The study is listed as completed. Its recorded start date is 2018-02-09, and its primary completion date is 2019-10-24. Abbott Medical Devices is listed as the sponsor. The phase is recorded as NA, allocation as NA, and masking as NONE.

Because the study had a single group and no randomized comparator, the design can describe events among participants treated under the study strategy, but it does not provide a like-for-like control group. The registry explicitly notes that the arms are not a like-for-like control comparison. This distinction matters when interpreting any event rate: an outcome observed in the study group alone does not show what would have occurred under a different treatment or duration of DAPT.

The primary endpoint was a participant count for NACE, reported by propensity score quintiles over the timeframe from 1 to 6 months. The registry lists 36 outcome measures, including secondary outcomes concerning NACE, stent thrombosis, and types of death. The statistical analysis details and numerical primary outcome estimates are not reported in the registry record. Further details of the study protocol, including how participants were selected and how follow-up was managed beyond the stated endpoint population rule, are also 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The number of participants analyzed includes subjects who completed follow up at the given time point. Subjects who were lost to follow-up or withdrew consent prior to that time point, without the endpoint of interest, are excluded from the denominator.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Composite of Net Adverse Clinical Endpoint (NACE), by Propensity Score Quintiles, measured over From 1 to 6 months.

The primary endpoint is the number of participants with a Net Adverse Clinical Endpoint (NACE), reported by propensity score quintiles. NACE is defined as a composite of all-cause death, all myocardial infarction under the modified Academic Research Consortium definition, stent thrombosis classified as ARC definite or probable, stroke, or major bleeding defined as Bleeding Academic Research Consortium (BARC) type 2-5. The timeframe is from 1 to 6 months.

A composite endpoint combines several event types into a single outcome. In general, this can summarize whether participants experienced any of a set of clinically important events, while also making the result less specific about which component occurred. The components can differ in nature and severity, so a composite count should not be interpreted as though every included event were interchangeable.

The outcome is expressed as a number of participants, not as a measure of event severity. The registry population rule says that participants analyzed at a time point completed follow-up at that time point; participants lost to follow-up or withdrawing consent before it, without the endpoint of interest, are excluded from that time point’s denominator. The numerical endpoint results and component-specific primary results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design tell us?

The study is described as prospective, open-label, non-randomized, and single-group. In a prospective study, participants are followed forward under the study plan. Open-label means masking is recorded as NONE. A single-group study can describe outcomes observed among participants receiving the study strategy, but it does not directly compare those outcomes with a concurrent randomized control group. In general, a treatment comparison needs a credible estimate of what would have happened to similar participants under the alternative strategy. This record does not include such a control arm.

Consequently, an observed event count in this group would be a description of participants in the study, not by itself an estimate of the difference caused by short-duration DAPT or the stent. Differences from outcomes in another study or in routine care would not automatically be valid treatment comparisons, because populations, follow-up, and methods may differ. The registry record does not report a comparative analysis plan.

How should the composite endpoint be understood?

NACE brings together all-cause death, myocardial infarction, stent thrombosis, stroke, and major bleeding. The registry specifies modified ARC criteria for myocardial infarction, ARC definite or probable for stent thrombosis, and BARC type 2-5 for major bleeding. The endpoint is a count of participants with the composite, rather than a count of all events. In general, a participant-level composite records whether a participant met at least one component definition; it does not indicate how many events that participant had unless that information is separately reported.

Composites can make an overall endpoint easier to summarize, but they combine distinct clinical events. An overall count cannot establish which component is most frequent or most influential. Component-specific results are important for interpreting what is behind a composite. The numerical primary results and component breakdown are not reported in the registry record.

What do the propensity score quintiles mean?

The endpoint title says that NACE is reported by propensity score quintiles. A propensity score is generally a score used to summarize the likelihood of a particular assignment or exposure based on measured characteristics. Dividing a score into quintiles creates ordered groups. However, the registry record does not explain the score’s target, included variables, construction, or analytical purpose in this study. It would be speculative to say that these groups represent risk levels, treatment assignments, or adjustment strata. The single-group design does not change simply because results are described across quintiles.

To assess such an analysis, readers would ordinarily want to know which covariates were used, how missing covariates were handled, whether the score was specified in advance, and how estimates across groups were calculated. Those details are not reported in the registry record. No numerical estimates by quintile are included in the information.

What does the planning illustration represent?

The sample-size material is described as a planning illustration based on the observed effect, not as the trial’s own design justification. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. For time-to-event tables, the stated quantity is the total number of events; for other tables, it is participants per arm.

These are hypothetical planning assumptions and should not be confused with the actual single-group study design. The illustration does not mean the study randomized participants equally between two arms, and a planning sample size is not observed power. The registry record does not report the trial’s own sample-size justification. The observed effect and the numerical planning outputs are not included in the record details, so no particular planning estimate can be interpreted from this discussion.

What would uncertainty estimates add?

In general, a confidence interval describes a range of values compatible with the data and the method used, and it communicates precision alongside a point estimate. A narrow interval indicates greater precision than a wide interval under the same method, but it does not remove concerns about design or bias. The registry record does not report confidence intervals or other uncertainty estimates for the primary endpoint. Without counts, denominators, and an analysis method, the precision of the primary result cannot be assessed.

For participant counts, interpretation also depends on the population included at each time point and on how incomplete follow-up is handled. The registry gives a denominator rule for the primary endpoint, but not the actual time-point denominators or a fuller missing-data analysis. These details are needed to understand how much information supports any reported estimate.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 36 outcome measures, and several secondary outcome descriptions concern composites, stent thrombosis, and categories of death. When a study reports many outcomes or repeated analyses, there can be multiple opportunities to observe an apparently notable result. In general, a prespecified multiplicity approach can help explain how multiple statistical tests were handled. The record details do not report a multiplicity adjustment, a hierarchy among endpoints, or which outcomes were designated for confirmatory testing. The number of analyses is listed as 0, and no statistical analysis details are included.

The primary endpoint population rule is specific: participants analyzed at a given time point completed follow-up at that time point; those lost to follow-up or who withdrew consent before that time point, without the endpoint of interest, are excluded from the denominator. This means the denominator may depend on follow-up completion at each time point. The registry does not report the actual denominators, the numbers excluded, or how missing follow-up was otherwise assessed.

In general, excluding participants with incomplete follow-up can affect interpretation if their outcome experience differs from that of participants who remain under observation. That possibility cannot be evaluated from the population rule alone. The record does not report imputation, sensitivity analyses, or assumptions about missing outcomes. It also does not describe whether analyses used an intention-to-treat population or another named analysis population. These methods are not reported in the registry record, so they should not be inferred.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: angina pectoris (5.7%), haemorrhage (5.6%), cardiac failure (3.1%), atrial fibrillation (2.8%), pneumonia (2.3%).

The registry adverse-event summary lists 963 participants at risk in the serious-event field and 374 participants affected. In the separate other-event fields, it lists 963 at risk and 357 affected. The summary also lists 55 deaths. These figures are reported as separate registry fields; they should not be combined or treated as a comparison between groups, because the study had one group and the fields have different labels.

The serious-event terms listed with percentages are Angina Pectoris, 5.7%; Haemorrhage, 5.6%; Cardiac Failure, 3.1%; Atrial Fibrillation, 2.8%; Pneumonia, 2.3%; and Myocardial Infarction, 1.9%. The registry entries do not state the denominator or follow-up period used for each listed percentage, nor do they provide an event-by-event assessment of relationship to the device or DAPT. The term list is a safety summary, not an estimate of the treatment’s comparative effect.

These adverse-event figures should also be kept distinct from the primary NACE endpoint. The record does not say which adverse-event entries overlap with NACE cases or how the death count relates to the primary endpoint analysis. The listed counts alone do not establish causation.

12. What the Result Does, and Does Not, Mean

This study documents a prospective evaluation of a XIENCE stent strategy with short-duration DAPT in participants described as being at high risk of bleeding and undergoing PCI. The registry lists an enrollment of 963 and identifies NACE from 1 to 6 months as the primary endpoint. It also records selected adverse-event counts and terms. These details show the focus and structure of the investigation, but they do not supply the numerical primary endpoint results in the record.

The design matters to what can be concluded. Because the study was single-group and non-randomized, it does not directly compare short-duration DAPT with a control strategy. Even if the study reports event counts, those counts describe outcomes within the study group. They cannot by themselves determine how outcomes would have differed under another treatment duration or strategy. The record itself notes that the arms are not a like-for-like control comparison.

The primary endpoint is a composite. A reported composite result would need to be read alongside its components, because death, myocardial infarction, stent thrombosis, stroke, and major bleeding are distinct outcomes. The registry defines these components but does not give the numerical primary estimates or component breakdown. It also does not explain the propensity score quintiles named in the endpoint title.

The safety summary is likewise descriptive. Counts and listed percentages do not establish whether an event was caused by the stent or DAPT, and the available information does not give the relevant attribution or follow-up details. The 55 deaths listed in the adverse-event summary should not be treated as the primary endpoint’s death component without a stated link between those records.

Accordingly, the record supports a description of the research question, study design, endpoint definitions, and selected safety reporting. It does not, in this summary, support a numerical assessment of NACE precision or a causal comparison with another treatment strategy. Any broader interpretation would require outcome estimates and analysis details not reported in the registry record.

13. Why This Trial Matters Statistically

Statistically, the study illustrates the difference between describing outcomes and estimating a comparative treatment effect. Its prospective follow-up can organize observations over time, but the single-group, non-randomized design has no concurrent randomized control arm. That means the study’s outcome counts, even when available, answer a descriptive question about the enrolled group rather than directly estimating the contrast between alternative strategies.

The primary endpoint also illustrates a common trade-off in composite outcomes. Combining death, myocardial infarction, stent thrombosis, stroke, and major bleeding can yield an overall summary, but the combined result does not reveal which event type drives it. Component-specific reporting is needed for a fuller statistical interpretation. Here, the endpoint definition is available, while its numerical results are not reported in the registry record.

The reference to propensity score quintiles raises another important issue: analytical labels alone do not explain an analysis. Interpretation depends on the score’s purpose, variables, construction, and use. Those details are not reported in the registry record. Without them, the quintiles cannot be assigned a clear statistical meaning beyond the fact that the endpoint is titled as being reported across them.

Finally, the denominator rule makes follow-up completion relevant to the outcome count. Excluding participants who are lost or withdraw before a time point, when they have not experienced the endpoint, may affect the analyzed population. The record gives the rule but not the resulting denominators or a fuller missing-data assessment. Together, these features show why endpoint definitions, analysis populations, uncertainty, and design must be read alongside headline counts.

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 for interpretation is the absence of a randomized control group. The study is single-group and non-randomized, so it does not provide a direct within-trial comparison against another DAPT duration or treatment strategy. Results from this design cannot be treated as if they came from a like-for-like randomized comparison.

The primary endpoint is defined, but its numerical estimates are not reported in the registry record details. Counts by propensity score quintile, time-point denominators, component results, and uncertainty estimates are also not reported. The title references propensity score quintiles, but the score’s construction and analytical role are not described. This prevents an assessment of what the quintile analysis represents.

The endpoint population rule excludes participants lost to follow-up or withdrawing consent before a time point if they had not experienced the endpoint. The record does not provide the number excluded at each time point, the denominators used, or sensitivity analyses for missing outcomes. The effect of incomplete follow-up on the reported results therefore cannot be assessed.

The registry lists multiple outcome measures but does not report a multiplicity strategy or a detailed statistical analysis plan in the information. The serious and other adverse-event summaries also lack, in these details, a stated event attribution and follow-up period. Finally, the registry record does not report the study’s sample-size justification or further protocol details needed to assess how the design and analysis were set in advance.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: XIENCE 28 Global Study — NCT03355742.
• Registry record last updated 2021-03-04; status last verified 2021-02.
• Results first posted 2021-02-08.
• 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.

18. Record Summary

XIENCE 28 Global Study (NCT03355742) is listed as a completed, prospective, multi-center, open-label, non-randomized, single-group study sponsored by Abbott Medical Devices. The recorded enrollment is 963. The start date is 2018-02-09, and the primary completion date is 2019-10-24.

The study evaluated XIENCE coronary drug-eluting stents with short-duration DAPT in participants at high risk of bleeding undergoing PCI. The primary endpoint was the number of participants with NACE, reported by propensity score quintiles, from 1 to 6 months. NACE combined all-cause death, myocardial infarction, stent thrombosis, stroke, or major bleeding.

The registry entries do not report numerical primary endpoint estimates or the methods behind the propensity score analysis. The study has no separate randomized control group, so its design supports description of the study group rather than a direct randomized treatment comparison.