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 Pulmonary Function After Hyperbaric Oxygen Therapy (NCT05088772), a registered phase not stated study. The primary outcome is Change in Percentage Predicted Forced Expiratory Volume in One Second (FEV1%).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05088772 |
| Phase | Phase not stated |
| Condition | Oxygen Toxicity |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 86 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Toronto |
| Results posted | Yes |
2. Clinical Question
Population
Patients receiving hyperbaric oxygen therapy for any indication at the Hyperbaric Medicine Unit, University Health Network, Toronto, ON, Canada, from 2016-2021. The registry record lists 86 enrolled participants.
Intervention
Hyperbaric oxygen therapy. Treatment was delivered at 2.0-2.4 ATA, with 1-3 air breaks. Specific treatment details were determined case by case and directed by the clinical team.
Comparator
The registry record describes one group receiving hyperbaric oxygen therapy and does not describe a separate control group. It is a prospective cohort, not a randomized comparison.
Primary question
How does percentage predicted forced expiratory volume in one second (FEV1%) change from pre-treatment baseline through the stated treatment follow-up points?
The cohort was intended to characterize pulmonary-function measurements during a course of hyperbaric oxygen therapy. Testing was performed before treatment and repeated after each 20 completed treatment cycles. The stated primary outcome was change from baseline in FEV1%, assessed after four weeks (20 treatments), eight weeks (40 treatments), and twelve weeks (60 treatments).
This question concerns within-participant change over time in a treated cohort. It does not, by itself, estimate how pulmonary-function changes compare with what would have occurred without hyperbaric oxygen therapy. The registry record does not describe a like-for-like comparison group, and the indication for treatment could vary among participants. The numerical primary-outcome results, including the mean changes and their confidence intervals, are not reported in the registry record. Consequently, the stated question and assessment schedule can be described, but the direction, size, and precision of any observed change cannot be established from the registry entry.
3. Trial Design
This study is registered as a prospective cohort study of patients receiving hyperbaric oxygen therapy at the Hyperbaric Medicine Unit at University Health Network in Toronto. The registry lists an enrollment of 86 and a completed status. The study start is recorded as 2016-02, and primary completion is recorded as 2021-06. Participants were recruited while receiving treatment for any indication at that unit.
The intervention is hyperbaric oxygen therapy, described at 2.0-2.4 ATA with 1-3 air breaks. The specific treatment details were determined on a case-by-case basis and directed by the clinical team. This description does not establish that every participant received an identical regimen. Further detail on individual exposure, adherence, or treatment variation is not reported in the registry record.
Pulmonary-function testing was scheduled before treatment and serially after each 20 completed treatment cycles. For the primary outcome, the stated assessment points were baseline, after four weeks (20 treatments), after eight weeks (40 treatments), and after twelve weeks (60 treatments). The record describes a single hyperbaric oxygen therapy group rather than a randomized allocation to different treatments. No concurrent control group is described, so changes over time in this cohort should not be read as a controlled estimate of treatment effect.
The registry lists pulmonary complications following hyperbaric oxygen therapy as a secondary outcome and four outcome measures overall. It lists no analyses. The statistical analysis plan, including the model used for repeated measurements, handling of missing observations, and any prespecified adjustment for multiple outcomes, is not reported in the registry record. A sample-size justification is also not reported in the registry record. The registry entry gives the enrollment count, but that count alone does not explain how the study was planned or whether it was designed to detect a particular change.
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 | Hyperbaric Oxygen Therapy - Experimental Group |
|---|---|
| STARTED | 86 |
| COMPLETED | 86 |
| NOT COMPLETED | 0 |
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 | Hyperbaric Oxygen Therapy - Experimental Group |
|---|---|---|
| Participants analysed | 86 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 53 |
| Age, Categorical: >=65 years | Participants | 33 |
| Age, Continuous | years | 42.5 (SD 15.0) |
| Sex: Female, Male: Female | Participants | 33 |
| Sex: Female, Male: Male | Participants | 53 |
| Race and Ethnicity Not Collected | Participants | — |
| Body Mass Index | kg/m*m | 27.1 (SD 10.3) |
| Comorbidities | total comorbidities | 123 |
| Medications | total medications | 115 |
| Smoking Status: Current Smoker | Participants | 23 |
| Smoking Status: Former Smoker | Participants | 16 |
| Smoking Status: Never Smoker | Participants | 47 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Percentage Predicted Forced Expiratory Volume in One Second (FEV1%), measured over The outcome measure was evaluated at baseline (pre-HBOT) and after four weeks (20 treatments), eight weeks (40 treatments), and twelve weeks (60 treatments).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Percentage of FEV1 |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in percentage predicted forced expiratory volume in one second, abbreviated FEV1%. FEV1 describes the volume of air a person can exhale in the first second of a forced breath; expressing it as a percentage of a predicted value places the measurement in relation to a reference value. The registry identifies the unit as percentage of FEV1 and specifies the mean as the summary measure.
The outcome was evaluated before hyperbaric oxygen therapy and after four weeks (20 treatments), eight weeks (40 treatments), and twelve weeks (60 treatments). At each timepoint, the value was defined as the highest result selected from at least three satisfactory pulmonary-function tests. This rule describes how the endpoint value was chosen at each assessment; it does not provide the observed values or explain how within-person change was analyzed.
FEV1% is a continuous measure, allowing pulmonary function to be described along a scale rather than only as a complication present or absent. Repeated measurements can describe how that measure varies across treatment follow-up. In general, a mean summarizes the central level of a continuous outcome, while a confidence interval conveys uncertainty around an estimated mean or change under the analysis used. Neither measure alone establishes that treatment caused a change, especially in a cohort without a described comparison group.
The registry record does not report the numerical baseline or follow-up means, mean changes, or confidence intervals for this endpoint. The size and precision of the pulmonary-function changes therefore cannot be interpreted from the registry entry.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a prospective cohort of 86 patients receiving hyperbaric oxygen therapy and specifies serial pulmonary-function assessment. It does not report numerical results for the primary outcome. In particular, it contains no reported mean FEV1% values, mean changes from baseline, or 95% confidence intervals at the stated follow-up points. The direction and magnitude of pulmonary-function change, and the precision of any estimate, are therefore not reported in the registry record.
The study design matters when interpreting the question. The record describes one group receiving treatment, without a concurrent comparator. A change observed between baseline and follow-up in a cohort would describe the participants' measurements over time; it would not, on its own, distinguish the contribution of treatment from other influences or the natural course of participants' underlying conditions. The cohort included patients receiving therapy for any indication, so the clinical context was not necessarily uniform.
The endpoint was assessed at baseline and after four, eight, and twelve weeks, corresponding to 20, 40, and 60 treatments. The registry defines each timepoint's value using the highest result selected from at least three satisfactory pulmonary-function tests. That endpoint rule is reported, but the registry does not specify the statistical model used to account for repeated measurements or explain how participants with incomplete follow-up were handled.
There are four outcome measures listed, including pulmonary complications following therapy, but the registry lists no analyses. No inferential results, such as p-values or confidence intervals for the primary outcome, are reported. It is therefore not possible to assess statistical evidence for change, compare the precision of estimates across assessment points, or determine whether any reported finding met a prespecified decision threshold.
The adverse-event entries list 86 participants at risk for serious adverse events, with zero affected, and 86 at risk for other adverse events, with 53 affected. The death count is zero. These counts describe what the registry reports; without further definitions, event-level details, or an analysis plan, they do not establish the completeness of event ascertainment or characterize the types and severity of the other events.
Overall, the registry record is informative about the cohort, treatment setting, assessment schedule, and how the primary endpoint was defined. It does not provide the outcome estimates needed to judge the observed pulmonary-function pattern or its statistical precision. Any conclusion about treatment-related effects would also require caution because the record does not describe a concurrent control group.
9. Statistical Methods Explained
The registry describes a continuous primary outcome summarized as a mean, with dispersion specified as a 95% confidence interval. It does not provide the numerical estimates or identify the analysis method used to produce them. The explanations below describe general statistical concepts relevant to this kind of outcome; they are not claims about analyses carried out in this cohort.
What does a mean change describe?
For a continuous outcome, a mean change summarizes the average difference between measurements at a follow-up assessment and baseline among the participants included in the analysis. It is a group-level summary, not a statement that every participant changed by the same amount. Individual changes may vary around the mean. The registry specifies change from baseline in FEV1%, but does not report the mean changes at the assessment points.
Repeated measurements from the same participant are related: a person's follow-up value is not independent of that person's baseline value in the way measurements from unrelated participants might be. General methods for longitudinal data can account for this within-person relationship. The choice of method can affect estimates and their uncertainty, particularly when follow-up is incomplete or measurements are uneven. The statistical method used for the repeated FEV1% measurements is not reported in the registry record.
How should a confidence interval be read?
In general, a confidence interval expresses the uncertainty around an estimate under the assumptions of the method used. A narrower interval indicates greater precision than a wider interval for the same type of estimate. It does not show the range of individual participant outcomes, and it does not by itself establish that an observed change was caused by treatment. The registry specifies 95% confidence intervals for the primary measure but reports no interval values.
A confidence interval should be interpreted alongside the estimate it surrounds, the study design, and the analysis population. Without the numerical mean change and its interval, readers cannot assess the estimated direction, magnitude, or precision. Without a comparison group, even a precisely estimated within-cohort change would not isolate the effect of treatment from other explanations.
What does the endpoint selection rule imply?
The record says that the endpoint at each timepoint was the highest value selected from at least three satisfactory pulmonary-function tests. This selection rule is part of the outcome definition. It does not reveal the distribution of test results, the number of tests actually completed by each participant, or how satisfactory tests were judged. Those details are not reported in the registry record. General interpretation should distinguish the defined endpoint from other possible ways of summarizing repeated test attempts, such as using all acceptable values.
What can over-dispersion mean in general?
For count outcomes, over-dispersion means that observed variability is greater than a model assumes. A model that does not allow for this extra variability may produce uncertainty estimates that are too small. This is a general consideration for count data and is not a reported finding about this primary continuous endpoint. The registry's listed secondary outcome concerns pulmonary complications, but its numerical results and analysis method are not reported.
What can a planning illustration tell readers?
A sample-size illustration based on an observed effect is a hypothetical planning calculation, not a measure of the study's achieved power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. Since the registry record does not report the observed primary effect, no such illustration can be tied to an interpretable numerical effect in this cohort. Also, the cohort description has one treatment group rather than two comparison arms, so a two-arm planning scenario is not the study's observed design.
The registry record does not report a sample-size justification, a prespecified statistical analysis plan, or the methods used to handle missing data. Those omissions prevent readers from assessing whether the analyses followed a prespecified approach, how the available data contributed to estimates, or whether the planned design was tied to a particular target effect. These are distinct questions from the enrollment count and the completion status.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, including the primary FEV1% outcome and a secondary outcome concerning pulmonary complications following hyperbaric oxygen therapy. The primary outcome is assessed at multiple follow-up points. Looking at more than one outcome or timepoint can raise multiplicity concerns: in general, making many statistical comparisons can increase the chance of at least one apparently unusual result when there is no underlying effect. Whether and how this issue was addressed depends on the prespecified analysis plan.
The statistical analysis plan and any multiplicity adjustment are not reported in the registry record. The record lists no analyses, so it does not provide p-values or confidence intervals with which to evaluate separate comparisons or an adjustment strategy. It would be inappropriate to assume that an adjustment was or was not performed.
Missing-data handling is also not reported in the registry record. Although assessments were scheduled at baseline and after 20, 40, and 60 treatments, the registry does not state how many participants contributed measurements at each point, whether participants missed visits, or how incomplete measurements entered the analysis. The number enrolled cannot establish the number analyzed at each follow-up.
The analysis populations are not described. It is not reported whether analyses included all enrolled participants, only those with measurements at a given timepoint, or another defined group. The registry also does not report how withdrawals, treatment completion, or unsuccessful testing were handled. These details are important because estimates based on different available participant groups may not represent the same cohort over time. No assumptions about missingness or sensitivity analyses are reported.
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 |
|---|---|---|---|
| Hyperbaric Oxygen Therapy - Experimental Group | 0 | 86 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Hyperbaric Oxygen Therapy - Experimental Group | 0 of 86 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Hyperbaric Oxygen Therapy - Experimental Group | 53 of 86 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hyperbaric Oxygen Therapy - Experimental Group |
|---|---|---|
| Anxiety | Psychiatric disorders | 18 of 86 |
| Ear Barotrauma | Ear and labyrinth disorders | 17 of 86 |
| Ocular Changes | Eye disorders | 16 of 86 |
| Seizure | Nervous system disorders | 2 of 86 |
| Congestive Heart Failure | Cardiac disorders | 1 of 86 |
The registry lists 86 participants at risk for serious adverse events and zero participants affected. It lists 86 at risk for other adverse events and 53 affected. The death count is zero. These are counts for the hyperbaric oxygen therapy group as recorded in the registry.
The serious-event count and other-event count refer to different categories, so they should not be treated as interchangeable. The registry does not list serious adverse-event terms, and the event descriptions, severity, timing, relationship to treatment, and method of collection are not reported in the registry record. It is also not reported whether the other-adverse-event count represents participants with at least one event or another counting convention, beyond the registry's affected-participant field.
Zero recorded serious adverse events does not establish that serious events were impossible or that event ascertainment was complete. Likewise, the other-event count does not, without event-level information and a comparison group, show whether events were attributable to therapy. These figures describe the registry entries and should not be read as a comparative safety estimate.
12. What the Result Does, and Does Not, Mean
The registry record supports a description of a prospective cohort in which patients receiving hyperbaric oxygen therapy underwent pulmonary-function testing before treatment and at specified treatment follow-up points. It also gives the primary endpoint definition, the enrollment count, and adverse-event counts. Those details clarify what was intended to be measured and the setting in which the cohort was assembled.
The record does not report the primary endpoint estimates. Without baseline and follow-up means, mean changes, and confidence intervals, it is not possible to say whether FEV1% increased, decreased, or remained similar in the cohort, or how precisely any change was estimated. The absence of reported analyses also means that no statistical significance or other inferential conclusion can be established from the registry entry.
Even if within-person change estimates were available, this cohort design would not by itself show what would have happened in the absence of treatment. The registry describes a single group rather than a concurrent control group, and participants received treatment for any indication. Changes over time could reflect multiple influences, and the registry does not report an analysis that separates these possibilities.
The adverse-event counts are descriptive registry entries. They do not provide event-level details or a controlled comparison, and they cannot alone establish treatment causality or fully characterize safety. The record is therefore most useful for understanding the planned measurement schedule and how the primary measure was defined, rather than for drawing conclusions about the magnitude or cause of pulmonary-function changes.
13. Why This Trial Matters Statistically
This cohort raises a useful statistical question about how to describe continuous pulmonary-function measurements collected repeatedly during treatment. The registry defines assessments at baseline and after 20, 40, and 60 treatments, and it specifies a mean change in FEV1% as the primary outcome. Repeated observations can show patterns across time, but interpreting those patterns requires clarity about the participant-level analysis and the uncertainty around each estimate.
The record also illustrates the distinction between a within-cohort trajectory and a comparative treatment effect. A longitudinal description can characterize observed measurements among treated participants. Without a concurrent comparator, that description cannot by itself isolate treatment effects from other influences. This distinction is especially relevant in a cohort recruited among patients receiving treatment for any indication, where clinical context may vary.
Endpoint construction matters as well. Selecting the highest result from at least three satisfactory tests at each timepoint is a specific rule, and readers need to understand that rule when interpreting the outcome. The registry provides the definition but not numerical results or further information about test acceptance, participant-level data, or analysis choices.
Finally, transparent reporting of estimates, confidence intervals, analysis populations, missing-data methods, and multiplicity handling would be needed to assess the strength and precision of findings. Those elements are not reported in the registry record. The study description remains informative about design and measurement, while the absence of posted outcome analyses limits statistical interpretation.
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 interpreting the registry entry is that numerical results for the primary outcome are not reported. The record specifies the mean and 95% confidence interval as the summary approach, but provides no values for baseline FEV1%, follow-up FEV1%, changes, or intervals. The magnitude, direction, and precision of any observed change therefore cannot be assessed.
The registry describes one treatment group and no concurrent comparator. The cohort includes people receiving hyperbaric oxygen therapy for any indication, so clinical reasons for treatment may differ. Without comparative data and relevant adjustment details, changes over time cannot be attributed specifically to the therapy. The registry does not report the statistical model, covariate adjustment, or analysis populations.
The primary endpoint is based on the highest value selected from at least three satisfactory pulmonary-function tests at each timepoint. Further details about the test-selection process, the number of tests completed, and the handling of unsatisfactory or unavailable tests are not reported. Participant counts at each follow-up, missing-data methods, and sensitivity analyses are also not reported in the registry record.
The treatment description permits case-by-case variation directed by the clinical team. The registry does not provide participant-level treatment details or explain how variation in treatment exposure was incorporated into analysis. It also lists four outcome measures but no analyses, and does not report how multiplicity was handled. These reporting gaps limit assessment of both the endpoint estimates and their uncertainty.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pulmonary Function After Hyperbaric Oxygen Therapy — NCT05088772.
- Registry record last updated 2024-05-16; status last verified 2024-05.
- Results first posted 2024-05-16.
- 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
The registry record describes a completed prospective cohort study of 86 patients receiving hyperbaric oxygen therapy for any indication at the Hyperbaric Medicine Unit, University Health Network, Toronto. Treatment was described at 2.0-2.4 ATA with 1-3 air breaks, with details determined case by case by the clinical team.
The primary outcome was change from baseline in percentage predicted FEV1%, assessed before treatment and after 20, 40, and 60 treatments. At each timepoint, the endpoint was defined as the highest result from at least three satisfactory pulmonary-function tests. Numerical primary-outcome estimates and analyses are not reported in the registry record.
The registry lists pulmonary complications following therapy as a secondary outcome and four outcome measures overall. It records zero serious adverse events among 86 at risk, 53 participants with other adverse events among 86 at risk, and zero deaths. Further event details and the statistical analysis plan are not reported.