Oxidative Stress in Asthma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Oxidative Stress in Asthma (NCT04512547), a non-randomized phase 2 study. The primary outcome is Percentage of Neutrophils in Peripheral Blood.

2. Clinical Question

The study concerns oxidative stress and regional airway remodeling and fibrosis in obese asthma. Its brief summary describes using 3D functional imaging with 129XeMRI and single cell RNA sequencing to investigate mechanisms in obese asthma participants and preclinical models. The named primary endpoint, however, is a blood measure: the percentage of neutrophils in peripheral blood. It is not itself a direct measure of regional airway remodeling or fibrosis.

The central statistical question is how this continuous measure was distributed in each group and whether the posted results estimate a difference between groups. The registry record does not report the values needed to answer that question. It therefore does not establish the size, direction, or precision of any group difference. Because participants were not randomly allocated, any observed group contrast would also need to be interpreted as an association between group membership and the endpoint, not automatically as an effect caused by an intervention.

3. Trial Design

The registry describes a phase 2, parallel study with nonrandomized allocation and single masking. It records an enrollment of 49 and a status of completed. The study start is listed as 2021-04-01 and primary completion as 2025-01-31. These are registry dates and do not, on their own, describe when individual participants were measured or how long they were followed.

The two groups are Obese Asthmatics and Obese Non-Asthmatics. The record describes the asthma group as obese patients diagnosed with asthma who would be approached at Duke. The non-asthma group is described as obese non-asthmatics collected from an IRB pre-approved Healthy Volunteer Data Repository. This recruitment description indicates that group membership was not assigned randomly by the study. The registry explicitly cautions that the arms are not a like-for-like control comparison.

Hyperpolarized 129XeMRI is listed as the intervention, with the registry categorizing its type as DRUG. The brief summary also describes 3D functional imaging and single cell RNA sequencing as tools for studying mechanisms. The record does not explain the masking arrangement, including who was masked, or give details of the intervention procedures. Further protocol details are not reported in the registry record.

The primary outcome is the percentage of neutrophils in peripheral blood, with a timeframe of up to 6 weeks. The registry lists seven outcome measures and two analyses, but the details of the other outcome measures and the analysis methods are not reported in the registry record. Although the study is marked completed, the numerical primary endpoint results are not reported in the registry record. Completion status does not by itself show whether a particular analysis was completed or what it found.

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

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.

Population: Participants who completed the study.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Neutrophils in Peripheral Blood, measured over Up to 6 weeks.

The primary endpoint measures the percentage of neutrophils in peripheral blood. It is recorded as a continuous measure, with the registry specifying a mean and standard deviation as the summary format and a timeframe of up to 6 weeks. A percentage expresses the neutrophil component of the blood measure; it does not directly quantify airway structure or fibrosis.

Continuous endpoints can describe a range of values rather than sorting participants only into categories. Reporting a mean gives a summary of the group’s values, while a standard deviation describes how spread out those values are around the mean. These summaries can help readers understand both the typical level of a measure and its variability. They do not show the full distribution, and they do not by themselves establish a difference between groups.

A peripheral blood neutrophil measure may be useful as a specified biological feature to compare across the study groups. The registry record does not state the endpoint’s biological rationale, define how the percentage was calculated, or explain how it relates to the imaging or sequencing measures. Those details are not reported in the registry record.

The registry record names the endpoint and its summary format but does not report group means, standard deviations, an estimated group contrast, a confidence interval, or a p value. Consequently, the magnitude and precision of the endpoint results cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

The endpoint is a continuous measure, and the registry specifies that it is summarized as a mean with a standard deviation. In general, a mean is a measure of the central level of the recorded values. A standard deviation describes their spread around that mean. The two summaries answer different questions: the mean locates the group’s values on the measurement scale, while the standard deviation indicates how much the individual observations vary.

These summaries are most informative when the distribution is also understood. A mean and standard deviation may not reveal skewness, outliers, or clusters in the data. The registry record does not report the endpoint’s distribution or individual observations, so those features cannot be assessed. Nor does it report the group-specific means and standard deviations needed to describe the endpoint numerically.

What would a group comparison mean?

A group comparison for a continuous endpoint generally estimates how the groups differ on the measurement scale. In a nonrandomized study, that contrast is descriptive unless the design and analysis support a stronger interpretation. Here, the two groups differ by asthma status and were not randomly assigned. Differences in their endpoint values could be associated with asthma status, but a raw contrast alone would not show that asthma status caused the difference. The registry record does not report an adjusted or unadjusted estimate for this endpoint.

In general, a confidence interval gives a range of values compatible with an estimate under the analysis assumptions. A narrow interval indicates greater statistical precision than a wide interval, while neither width nor location alone establishes clinical importance. A p value is a measure of how compatible the data are with a specified statistical null model. It does not measure the probability that a hypothesis is true, and it does not communicate the size of an effect. The registry record does not report a confidence interval or p value for the primary endpoint.

What role does variability play?

Variation among participants affects how precisely a group mean or contrast can be estimated. In general, greater variability makes it harder to distinguish a group contrast from the background spread of observations, all else being equal. This is why the endpoint’s standard deviation and the number of participants contributing endpoint data matter. The registry record does not report endpoint-specific participant counts or standard deviations, so the precision of a primary endpoint estimate cannot be judged.

When data are more variable than an analysis model expects, the model may understate uncertainty. This is called over-dispersion in settings where the assumed variability is too small. General responses include using a model that accommodates extra variability or reporting uncertainty robustly, but the appropriate approach depends on the data and design. The registry record does not describe the primary endpoint model or report evidence about over-dispersion; no particular method can be attributed to this study.

How should the planning illustrations be read?

The stated planning assumptions describe an illustration based on the observed effect, rather than the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. For time-to-event illustrations, the stated quantity is the total number of events using the Schoenfeld approach; other illustrations are expressed as participants per arm.

These assumptions do not establish that the study used those conditions when it was planned, and they do not describe the actual analysis. Sample-size illustrations based on an observed effect are planning scenarios, not observed power. Observed power is not a substitute for examining the estimated effect and its uncertainty. The numerical illustration results and the observed primary endpoint effect are not reported in the registry record, so no planning quantity can be interpreted from the record alone.

What analysis details remain unknown?

The record lists two analyses but does not describe the statistical tests, model specifications, covariates, handling of missing observations, or analysis populations. It also does not report whether any interim analyses were planned or conducted, or how the sample size was justified for the study’s own design. These details are not reported in the registry record. General statistical principles cannot fill in those study-specific choices.

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("Obese Asthmatics", "Obese Non-Asthmatics")
n   <- c(26, 8)
m   <- c(57.3, 55.4)
sp  <- c(7.4, 10.2)
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  Obese Asthmatics  26  57.300  7.400  54.311  60.289
CARM  Obese Non-Asthmatics  8  55.400  10.200  46.873  63.927

11. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures and two analyses. It does not report how those outcomes and analyses were organized, which outcomes were treated as primary or secondary beyond the named primary endpoint, or whether any adjustment for multiple comparisons was planned or used. The multiplicity strategy is not reported in the registry record.

In general, testing multiple outcomes or contrasts can increase the chance of at least one apparently unusual result under a collection of null hypotheses. A prespecified strategy can help readers understand which tests were confirmatory and how uncertainty was handled. Without the study’s analysis plan or a multiplicity statement, the registry record does not show whether such a strategy was used. This does not imply that an adjustment was necessary or absent; it means the approach is unknown.

The registry record does not report the number of participants with primary endpoint data, the number excluded from analysis, or the reasons for missing measurements. It also does not describe imputation, complete-case analysis, or sensitivity analyses for missing data. These details are not reported in the registry record. Missingness matters because the participants with recorded measurements may differ from those without measurements; the direction and effect of any such difference cannot be determined without information.

The analysis populations are also not specified. The enrollment is 49, while the safety entries give group-specific numbers at risk for the adverse-event summaries. Those safety denominators do not establish how many participants contributed to the primary endpoint analysis. The registry record does not identify an intention-to-treat, per-protocol, or other analysis population, and no such population should be inferred.

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.

Most frequent non-serious adverse event terms

The safety summary lists serious adverse events, other adverse events, and deaths separately for Obese Asthmatics and Obese Non-Asthmatics. For serious adverse events, 0 participants were affected among 26 at risk in the Obese Asthmatics group, and 0 were affected among 8 at risk in the Obese Non-Asthmatics group. For other adverse events, 6 participants were affected among 26 at risk in the Obese Asthmatics group, and 1 was affected among 8 at risk in the Obese Non-Asthmatics group. The record separately lists 6 deaths and 1 death, respectively.

These are descriptive counts. The registry record does not report the causes, timing, severity details for the other events, or whether events or deaths were judged related to the intervention or study participation. The death entries should not be interpreted as deaths caused by the intervention. The serious-event terms are not listed in the record.

The groups are nonrandomized and differ in asthma status, and their safety counts are not a controlled causal comparison. The at-risk counts in this summary should not be assumed to be the number analyzed for the primary endpoint. The registry record does not provide further detail that would connect the safety entries to endpoint participation or explain follow-up completeness.

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

The registry record documents a completed, nonrandomized phase 2 study involving obese participants with asthma and obese participants without asthma. Its named primary endpoint is the percentage of neutrophils in peripheral blood, measured over a timeframe of up to 6 weeks. These details establish the study question and design features, but they do not establish a numerical result for the endpoint.

The group means, standard deviations, and any estimate of a contrast are not reported in the registry record. As a result, the posted information does not indicate whether the groups differed on this endpoint, in which direction a difference might lie, or how precisely it could be estimated. It is not possible to draw a conclusion about statistical significance or magnitude from the registry record’s primary endpoint information.

Even if a group difference were reported, the nonrandomized design would require careful interpretation. The groups were defined by asthma status and are not a like-for-like control comparison. A difference could be associated with group membership without showing that the intervention caused it. The record does not report an adjusted analysis that would address other group differences.

The study’s topic includes oxidative stress, airway remodeling, and fibrosis, and its brief summary describes imaging and single cell RNA sequencing as ways to investigate mechanisms. The blood endpoint is not itself a direct measure of those structural or imaging outcomes. The registry record does not provide results linking the primary endpoint to those mechanisms.

The safety counts are also descriptive, with no reported attribution of events or deaths to the intervention. Overall, the registry record defines the study setting and endpoint but does not provide enough numerical primary outcome information to characterize the observed endpoint results.

14. Why This Trial Matters Statistically

This study illustrates why design details are essential when reading a clinical comparison. The groups are both obese, but one group has asthma and the other does not. Because allocation is nonrandomized, the contrast is not equivalent to a randomized treatment comparison. Group differences could reflect asthma status or other differences that the registry record does not describe.

The endpoint also highlights the importance of matching the scientific question to the measurement. The stated primary outcome is a peripheral blood neutrophil percentage. The study’s broader topic concerns oxidative stress and regional airway remodeling and fibrosis, but a blood measure is not a direct structural assessment of the airways. Readers need endpoint results and a clear explanation of how different measurements relate before drawing conclusions across them.

Statistically, an endpoint name and a study status do not replace an estimate. Means, variability, analysis population, and uncertainty would be needed to characterize the primary result. The registry record does not report those numerical endpoint results or the analysis details needed to evaluate them.

The record also demonstrates why safety counts need context. Counts by group describe what was recorded, but without event definitions, timing, and attribution they do not establish whether the study intervention caused an event. In a nonrandomized study, that caution applies to both outcome and safety comparisons.

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 direct limitation for interpreting the primary endpoint is that its numerical results are not reported in the registry record. Group means, standard deviations, a group contrast, and measures of uncertainty are absent. The endpoint’s observed direction, size, and precision therefore cannot be evaluated.

The registry identifies a nonrandomized comparison and explicitly cautions that the groups are not a like-for-like control comparison. Participants in the two groups differ in asthma status, and the record does not report methods for adjusting for other group differences. Causal interpretation of any contrast would therefore be unwarranted on the registry information alone.

The registry describes the primary endpoint timeframe as up to 6 weeks but does not report the exact measurement schedule or how many participants contributed data at each time. It does not specify missing-data handling, analysis populations, endpoint model, or multiplicity approach. These omissions make it difficult to assess the analysis plan and the representativeness of any endpoint result.

The brief summary describes imaging and single cell RNA sequencing, while the primary endpoint is a peripheral blood measure. The registry record does not explain how these measures were linked analytically or report whether the imaging and sequencing findings support an interpretation of the blood endpoint.

The safety summary lists events and deaths but does not describe causes, timing, or attribution. The record does not explain the masking arrangement or offer the study’s sample-size justification. These matters limit assessment of study conduct and interpretation beyond what the registry entries directly state.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Oxidative Stress in Asthma — NCT04512547.
• Registry record last updated 2026-03-23; status last verified 2025-03.
• Results first posted 2026-03-23.
• 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

The registry record describes NCT04512547, titled “Oxidative Stress in Asthma,” as a completed phase 2, parallel, nonrandomized, single-masked study with enrollment of 49. It concerns obese participants with asthma and obese participants without asthma. Hyperpolarized 129XeMRI is listed as the intervention. The brief summary describes imaging and single cell RNA sequencing to investigate mechanisms related to obese asthma.

The primary endpoint is the percentage of neutrophils in peripheral blood, summarized as a mean with standard deviation over a timeframe of up to 6 weeks. The registry lists seven outcome measures and two analyses. Numerical results for the primary endpoint and details of its statistical analysis are not reported in the registry record.

Safety entries report serious events, other events, and deaths by group, but do not state causality. The nonrandomized groups should not be interpreted as a like-for-like control comparison.