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
SCAST was a phase 3 randomized, parallel-group trial evaluating candesartan cilexetil compared with placebo in patients with stroke.
| Feature | SCAST |
|---|---|
| NCT ID | NCT00120003 |
| Title | Scandinavian Candesartan Acute Stroke Trial (SCAST) |
| Status | Completed |
| Start date | 2005-06 |
| Primary completion date | 2010-09 |
| Lead sponsor | Ullevaal University Hospital |
| Condition | Stroke |
| Design | Randomized, parallel, quadruple masked |
| Primary purpose | Treatment |
2. Clinical Question
Population
Patients with stroke enrolled in the Scandinavian Candesartan Acute Stroke Trial.
Intervention
Candesartan cilexetil.
Comparator
Placebo.
Primary question
The trial evaluated whether candesartan cilexetil affected clinical outcomes after acute stroke compared with placebo.
3. Trial Design
Randomized
Quadruple masked
Parallel assignment
Two intervention groups
| Arm | Intervention |
|---|---|
| Candesartan arm | Candesartan Cilexetil (drug) |
| Control arm | Placebo (drug) |
4. Endpoints
| Endpoint | Definition | Time frame |
|---|---|---|
| Primary endpoint | Death or major disability (defined by the modified Rankin scale) | 6 months |
| Primary endpoint | The composite event "vascular" death, myocardial infarction, or stroke | During the first 6 months |
5. Planned Analysis
The ClinicalTrials.gov record identifies the primary outcomes but does not report posted statistical analyses or outcome estimates.
For a time-framed clinical endpoint such as death or major disability assessed using the modified Rankin scale, statistical analysis would typically compare outcome distributions between randomized groups using methods appropriate for ordinal or binary clinical outcomes, depending on the prespecified analysis plan.
For a composite vascular endpoint consisting of vascular death, myocardial infarction, or stroke during the first 6 months, analysis would typically focus on comparison of time-to-first-event or cumulative event rates between randomized groups.
No formal statistical analyses were posted to ClinicalTrials.gov for the listed primary endpoints.
6. Statistical Methodology
Randomization
Randomization is the foundation of the treatment comparison because it balances measured and unmeasured prognostic factors, allowing differences in outcomes between groups to be attributed to the randomized intervention under appropriate assumptions.
Modified Rankin scale outcomes
The modified Rankin scale is an ordinal measure of disability. Statistical approaches for ordinal outcomes must account for the ordered nature of categories rather than treating every category difference as identical.
Composite endpoints
A composite endpoint combines multiple clinical events into a single outcome measure. Interpretation requires understanding which components contribute most strongly to the overall result because individual components may differ in frequency and clinical importance.
Time-to-event analysis
When outcomes occur over follow-up time, survival analysis methods account for varying follow-up duration and censoring. These methods estimate event patterns while incorporating patients whose complete outcome status is not observed.
7. Statistical Methods Explained
Why use randomization?
Randomization creates comparable treatment groups at the start of a trial and reduces the influence of confounding variables.
Why is the modified Rankin scale statistically challenging?
The scale represents ordered categories. A move from one category to another reflects a change in disability status, but the distance between categories is not necessarily equal.
Why use a composite vascular endpoint?
Composite endpoints can increase the number of observed events, but interpretation depends on the contribution and clinical relevance of each component.
Why does follow-up time matter?
Patients may experience events at different times, and survival methods incorporate this timing rather than only counting whether an event occurred.
8. Limitations
- No posted analyses: The registry does not report statistical estimates, confidence intervals, or p-values for the listed primary endpoints.
- Composite interpretation: Composite outcomes require careful evaluation of their individual components.
- Endpoint structure: Disability outcomes and vascular events require methods aligned with their measurement scale and clinical interpretation.
- Follow-up considerations: Time-dependent outcomes require appropriate handling of censoring and variable follow-up.
9. Why This Trial Matters Statistically
SCAST is a useful statistical teaching example because it combines randomized trial design, disability measurement, and composite clinical outcomes in an acute disease setting.
| Concept | Application |
|---|---|
| Randomized controlled trial | Comparison of candesartan cilexetil and placebo |
| Masked design | Quadruple masking |
| Ordinal outcomes | Modified Rankin scale disability assessment |
| Composite endpoints | Vascular death, myocardial infarction, or stroke |
| Time-to-event analysis | Events assessed during follow-up |
10. Sources
- ClinicalTrials.gov record: NCT00120003