Stroke and CPAP Outcome Study 3: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Stroke and CPAP Outcome Study 3 (NCT06029959), a na na study. The primary outcome is CPAP Adherence.

2. Clinical Question

SCOUTS3 addresses treatment use in a specific care context: inpatient stroke rehabilitation, followed by the period after CPAP initiation. Its primary measure describes how much CPAP participants used on a nightly basis over the stated follow-up period. It is an adherence measure, not a direct measure of sleep apnea severity, stroke recovery, or the effect of CPAP compared with no CPAP.

3. Trial Design

SCOUTS3 is registered as a completed, single-group study sponsored by the University of Washington. The record lists an enrollment of 36 and one arm, called the SCOUTS3 Optimization Arm. The start date is 2023-10-01, and the primary completion date is 2024-09-30. The phase is listed as NA. Allocation is listed as NA, masking as NONE, and the model as SINGLE GROUP.

The arm description says participants with acute ischemic stroke or intraparenchymal hemorrhage within the past 30 days would be tested for obstructive sleep apnea using a single-night portable test during inpatient rehabilitation. Eligible participants would then start CPAP. The registry also lists CPAP technical support, MET, and a Mobile Health intervention. How those behavioral components were combined with CPAP, or which participants received each component, is not reported in the registry record.

A single-group design describes outcomes in participants receiving the study approach, but it does not provide a concurrent control for distinguishing the approach from other influences. Changes over time could reflect the study intervention, the rehabilitation setting, participant characteristics, or other factors. Without a control group, the design does not estimate a between-group treatment effect.

The registry lists one primary outcome measure and zero analyses. A numerical primary outcome estimate, its variability, and an inferential analysis are not reported in the registry record. Completion status and enrollment describe the trial record, but do not establish what level of adherence participants achieved.

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.

Before assignment: A single-night portable sleep apnea test was performed at a mean of 16.0 days from stroke onset and 4.0 days from IPR admission.

Overall Study

Reasons for not completing this period:

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 CPAP Adherence, measured over From CPAP initiation after study enrollment and sleep apnea testing to 90 days from CPAP initiation.

The primary endpoint is CPAP adherence, measured as mean hours of CPAP use per night. The stated timeframe begins with CPAP initiation after study enrollment and sleep apnea testing and continues to 90 days from initiation. The description characterizes the measure as mean nightly use during and after inpatient rehabilitation over 3 months.

Mean nightly hours provide a continuous summary of the amount of device use over the measurement period. This can describe adherence in a way that accounts for the degree of use, rather than simply classifying a participant as using or not using CPAP. It is important, however, to know how nightly observations were collected, how nights without recorded use were treated, and how incomplete follow-up was handled. Those details are not reported in the registry record.

The endpoint measures device use, not whether CPAP improved sleep apnea, stroke outcomes, or any other clinical outcome. A mean also does not show how use varied among participants or across nights. Without a reported mean and measure of spread, the posted record does not establish the adherence level or its precision. The clinical rationale describes OSA as common after stroke and notes concern about outcomes, but that rationale is distinct from the endpoint actually registered.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered primary measure is a continuous outcome: mean nightly hours of CPAP use. For a continuous measure, the mean summarizes the center of the observed values. It is most informative when accompanied by a measure of variability and a clear account of how each participant contributes to the summary. The registry names standard deviation as the dispersion measure, but no numerical mean or standard deviation is reported in the registry record.

What does a mean describe?

In general, a mean combines observed values into one average. It can be useful for describing typical use across a group, but it can conceal substantial differences between participants. For example, a group average alone does not show whether use was similar across participants or whether it was concentrated among a subset. It also does not describe whether nightly use changed over time. The registry describes a mean over the follow-up period, but the exact calculation and the handling of night-level observations are not reported in the registry record.

Why report a standard deviation?

In general, a standard deviation describes how spread out measured values are around their mean. A small or large standard deviation has meaning only in relation to the measurement and the population being summarized. For nightly CPAP hours, it could help readers understand how much use varied, but it does not indicate the precision of the mean in the same way a confidence interval does. The registry names standard deviation for the endpoint, but gives no value.

What would a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimated quantity under a statistical model and its assumptions. A narrower interval indicates greater statistical precision than a wider interval, while neither interval alone determines clinical importance. A confidence interval for this study’s mean adherence would help assess how precisely the group average had been estimated. No interval is reported in the registry record, and no primary analysis is listed.

Why does the single-group design matter?

A study with one group can describe outcomes among participants receiving the study approach. It cannot, without additional assumptions or external comparison data, isolate the effect of that approach from other explanations. In general, a concurrent control helps account for factors that affect both groups over the same period. SCOUTS3 is identified as single-group and does not have a like-for-like control comparison. As a result, the registered design is descriptive rather than a randomized test of intervention versus control.

What can be said about sample-size planning?

The planning illustration described for the analyses uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a fraction of the observed effect. That is a planning framework, not a description of the SCOUTS3 design: the registry identifies a single group, not two randomized arms. A planning calculation based on an observed effect is not observed power, and any illustrative sample size should not be interpreted as the number actually analyzed or as evidence that the study had a particular probability of detecting an effect. The observed primary outcome estimate needed to understand such an illustration is not reported in the registry record.

In general, power calculations depend on assumptions about the target effect, variability, significance level, allocation, and analysis. They can illustrate how required sample size changes under different assumptions, but they do not replace an estimate with uncertainty from the completed study. The registry record does not report the trial’s own sample-size justification. Its enrollment of 36 should therefore be read as the registered enrollment, not as evidence about the assumptions used to plan the study.

For repeated nightly measurements, observations within a participant may be related rather than independent. In general, analysis methods need to account for such clustering when the outcome is built from repeated observations. Over-dispersion, in general, means that observed variation is greater than a model assumes; ignoring it can make uncertainty estimates too small. The registry does not report whether nightly observations were analyzed individually, aggregated by participant, or handled with a model that accounts for within-participant dependence. No such method should be assumed.

Interpretation also depends on the analysis population. In general, an enrolled participant may not contribute complete endpoint data, and the number analyzed can differ from enrollment. The registry does not state the population used for the primary analysis, the amount of missing adherence data, or the approach to incomplete follow-up. Those omissions prevent assessment of how representative the endpoint estimate would be, even if a summary were available.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("SCOUTS3 Optimization Arm")
n   <- c(30)
m   <- c(3.1)
sp  <- c(2.6)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  SCOUTS3 Optimization Arm  30  3.100  2.600  2.129  4.071

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure, CPAP adherence, and zero analyses. No primary analysis result, hypothesis test, confidence interval, or secondary outcome analysis is reported in the registry record. The record does not describe a multiplicity adjustment or a hierarchy of statistical tests. With no reported analyses, it is not possible to determine whether multiple comparisons were made or how they were handled.

In general, multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. If many tests are considered, the chance of at least one apparently notable result can increase unless the analysis plan accounts for that process. A registered primary outcome helps identify the main question, but it does not by itself show which analyses were performed or whether any multiplicity procedures were used. Those analysis details are not reported in the registry record.

The registry does not state how missing nightly CPAP observations or incomplete follow-up were handled. It also does not report the number of participants contributing endpoint data, the definition of an analyzable observation, or any imputation or sensitivity analysis. In general, missing data can affect both the estimated mean and the uncertainty around it, especially if the probability of missingness is related to use. Without the relevant counts and methods, the direction or extent of any such influence cannot be assessed.

The analysis population is not reported in the registry record. It is therefore unclear whether the primary endpoint was intended to include all enrolled participants, only participants who initiated CPAP, or another defined group. No inference about the completeness or representativeness of the analyzed group is possible from the enrollment figure alone.

12. 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.

The adverse-event record lists the SCOUTS3 Optimization Arm with 36 participants at risk for serious adverse events and 0 affected. It also lists 36 at risk for other adverse events and 0 affected, with 0 deaths. No serious adverse-event terms are listed.

These figures are counts in the registry record. They do not establish that no adverse events occurred outside the recorded categories, nor do they show how events were defined, collected, or reviewed. The record does not report the duration or completeness of safety follow-up, the criteria used to classify seriousness, or whether the listed categories capture every event of interest. Zero recorded events should therefore be read as a registry count, not as proof of absence of risk.

The single-group design also limits comparative safety interpretation. Without a concurrent control group, the counts cannot estimate whether event frequency differs from another care approach. The registry does not provide further safety analyses or event descriptions that would support a more detailed assessment.

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

The registry record establishes that SCOUTS3 studied a strategy for improving CPAP use when treatment begins during inpatient stroke rehabilitation. It identifies a single-group design, an enrollment of 36, and a primary endpoint of mean nightly CPAP hours from initiation through 90 days. It also identifies behavioral components in addition to CPAP. These details define the study’s focus and the setting in which the question was asked.

The record does not report the mean adherence result, its standard deviation, a confidence interval, or an analysis. It therefore does not show how many hours participants used CPAP on average or how much adherence varied. The recorded completion status does not fill that gap. Without endpoint results, the central descriptive question remains unanswered in the registry record.

Even a reported mean from this design would have a limited interpretation. It could describe use among participants in the study, but there is no concurrent control group for estimating the effect of the support approach. The record cannot establish whether CPAP technical support, MET, or Mobile Health changed adherence relative to another strategy. It also cannot establish effects on stroke recovery or other clinical outcomes from the primary adherence endpoint.

The adverse-event counts are likewise bounded: the record reports zero serious events, zero other events, and zero deaths in the listed group, but does not provide detailed event definitions or further safety analyses. Those counts do not demonstrate that the interventions are free of risk.

Thus, the registered aim and design are clear, but the posted results are insufficient to assess the observed adherence level, precision, or intervention effect. The record supports description of what the study set out to measure, not a conclusion about the success or failure of its approach.

14. Why This Trial Matters Statistically

SCOUTS3 raises a measurement question with practical statistical importance: how to characterize use of a device across nights when treatment starts during inpatient rehabilitation and continues afterward. A mean nightly-hours endpoint gives a direct summary of use, while the stated follow-up connects the rehabilitation period to use after discharge. The endpoint is distinct from a clinical outcome and should be interpreted as a measure of adherence.

The design also makes the distinction between description and causal comparison especially important. A single-group study can report how participants used CPAP under the study approach. It cannot, by itself, determine what would have happened under another support strategy. This distinction matters when interpreting any future summary: an observed group mean is not the same as an estimated intervention effect.

Reporting the mean alongside variability, uncertainty, analyzed sample size, and missing-data handling would be important for assessing the strength of the descriptive evidence. Repeated nightly measurements may also call for clear explanation of how individual observations are summarized and whether within-participant dependence is considered. Those methods and results are not reported in the registry record.

The registry identifies an enrollment of 36 and a completed status, but the absence of primary outcome analyses means that readers cannot judge the level or precision of adherence. The record is useful for defining the intended clinical setting and outcome, while the missing numerical results limit statistical interpretation.

15. 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 consequential limitation for interpreting this record is that the primary outcome result is not reported in the registry record. There is no numerical mean, standard deviation, confidence interval, or analysis listed. The registered enrollment of 36 does not indicate how many participants contributed usable adherence observations or how complete follow-up was.

The study is single-group, with no randomized or concurrent control comparison. This means that outcomes cannot be contrasted against a control condition to estimate the effect of the study approach. The intervention list names CPAP technical support, MET, and a Mobile Health intervention, but details of their content, timing, and use are not reported in the registry record. The contribution of any individual component therefore cannot be separated.

The endpoint is defined as mean nightly hours of CPAP use across a period spanning inpatient rehabilitation and the time after initiation through 90 days. However, the record does not describe the adherence data source, the exact calculation of the mean, how nights without recorded use were handled, or how participants with incomplete observations were treated. The analysis population and missing-data approach are also not reported.

The safety information is limited to aggregate counts. Event definitions, ascertainment procedures, follow-up completeness, and detailed event descriptions are not reported in the registry record. The zero counts therefore have limited interpretive scope.

Finally, the registry does not report the trial’s sample-size justification or a detailed statistical analysis plan. The design and outcome are identifiable, but the available record does not allow readers to assess the planning assumptions, analysis choices, or precision of the primary finding.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Stroke and CPAP Outcome Study 3 — NCT06029959.
• Registry record last updated 2025-10-08; status last verified 2025-09.
• Results first posted 2025-10-08.
• 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.

19. Record Summary

SCOUTS3 (NCT06029959) is a completed, single-group study sponsored by the University of Washington. The registry lists an enrollment of 36, one SCOUTS3 Optimization Arm, no masking, and a primary completion date of 2024-09-30. The study concerns CPAP use among people with stroke and obstructive sleep apnea in inpatient rehabilitation and afterward.

The primary endpoint is mean nightly hours of CPAP use from initiation through 90 days. The registry lists CPAP, CPAP technical support, MET, and a Mobile Health intervention. A numerical primary outcome result and analysis are not reported in the registry record. The adverse-event record lists 0 serious events, 0 other events, and 0 deaths among 36 at risk.