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 Hyperbaric Oxygen Therapy in Sickle Cell Pain (NCT03412045), a na na study. The primary outcome is Analgesic Received in MME (Morphine Milligram Equivalents).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03412045 |
| Phase | NA |
| Condition | Vaso-occlusive Crisis, Sickle Cell Anemia Crisis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Nebraska |
| Results posted | Yes |
2. Clinical Question
Population
Adults admitted to hospital with an uncomplicated acute sickle cell pain crisis were the intended participants. The registry summary identifies vaso-occlusive crisis and sickle cell anemia crisis as conditions of interest. It describes excluding acute chest syndrome, acute myocardial infarction, and stroke from the eligible presentation. The recorded enrollment is 8. The registry record does not report further participant characteristics, such as baseline pain severity or the distribution of sickle cell diagnoses.
Intervention
The intervention was hyperbaric oxygen therapy. The registry summary describes 1-3 sessions, depending on response to therapy, with each session lasting approximately two hours. This describes the planned treatment approach; the record does not report how many sessions participants actually received or other details of treatment delivery.
Comparator
The primary outcome description says each patient serves as their own control. Analgesic use during the intervention admission was to be compared with use during the participant’s previous hospital admission. This is not a randomized concurrent control group: the registry identifies the study model as single group and states that the comparison is not a like-for-like control comparison. The record does not report details about the previous admissions or how comparable they were to the intervention admissions.
Primary question
The primary question concerns the total analgesic administered from admission to discharge, expressed in morphine milligram equivalents (MME). The intended comparison is whether a participant’s recorded analgesic amount during an admission involving hyperbaric oxygen differs from the amount during that participant’s previous hospital admission. The registry lists the median and inter-quartile range as the outcome summary, but does not report the observed values or an analysis result.
3. Trial Design
The registry describes a completed, single-group study sponsored by the University of Nebraska. Its title is “Hyperbaric Oxygen Therapy in Sickle Cell Pain.” The recorded enrollment is 8, and the study status is completed. The recorded start date is 2022-09-01 and the primary completion date is 2025-06-05. The phase is recorded as NA. Allocation is recorded as NA, and masking is listed as none.
The study is described as a preliminary convenience sample of patients admitted to hospital for vaso-occlusive sickle cell crisis. Participants were to receive hyperbaric oxygen therapy during one hospital admission. The registry describes the intervention as 1-3 treatment sessions, depending on response, with each session approximately two hours long. It describes the primary outcome comparison as each participant’s analgesic use during the intervention admission versus use during the participant’s previous admission.
This design differs from a randomized trial with concurrent treatment and control groups. A participant’s earlier admission is a historical comparator, not an admission assigned under the same study conditions at the same time. Changes between admissions could reflect differences in the crisis, care, or other circumstances; the registry record does not report information that would allow those possibilities to be assessed. The single-group model and absence of masking also matter when interpreting outcomes that involve clinical decisions or participant self-assessment.
The registry summary says pain was to be assessed by participants using a visual analog scale before and after treatment, and hospital length of stay was to be tracked. Hospital length of stay is listed as a secondary outcome. The registry record does not report the actual number of treatment sessions, details of the scale measurements, or outcome results. It lists 2 outcome measures and 0 analyses.
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 | Patients Experiencing Acute Sickle Cell Crisis |
|---|---|
| STARTED | 8 |
| COMPLETED | 8 |
| 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 | Patients Experiencing Acute Sickle Cell Crisis |
|---|---|---|
| Participants analysed | 8 | |
| Age, Customized: 19 years and older | Participants | 8 |
| Sex: Female, Male: Female | Participants | 3 |
| Sex: Female, Male: Male | Participants | 5 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Analgesic Received in MME (Morphine Milligram Equivalents), measured over admission to discharge.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | MME (morphine milligram equivalents) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is total analgesic administered to a participant during the hospital stay, expressed in morphine milligram equivalents (MME), from admission to discharge. Expressing different analgesic medications in a common unit is intended to make their total amounts comparable on a shared scale. The registry specifies a median and inter-quartile range for describing this endpoint. The median represents the middle of an ordered set of observations, while the inter-quartile range describes the spread of the middle portion of those observations. These summaries can be useful when measurements are skewed or when unusually high or low values make a mean less representative.
The stated comparison is within participant: analgesic use during the hyperbaric oxygen admission is compared with use during the participant’s previous hospital admission. This approach can account for characteristics that remain stable within an individual, but it does not ensure that the circumstances of the admissions are comparable. The registry record does not report the median, inter-quartile range, participant-level values, or a statistical test for the primary endpoint. Therefore, the direction and magnitude of any observed difference, and its precision, are not reported in the registry record.
The registry summary also describes self-assessed pain using a visual analog scale before and after treatment, and lists hospital length of stay as a secondary outcome. The record does not provide results for these measures.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s intended question and design, but it does not report a result for the primary endpoint. It identifies analgesic use in MME from admission to discharge as the primary outcome and describes comparing treatment-admission use with use during a participant’s previous admission. No median, inter-quartile range, effect estimate, confidence interval, or hypothesis-test result is reported in the registry record. Accordingly, the posted information does not establish the size, direction, or precision of a difference in analgesic use.
The design calls for caution even if outcome values are considered elsewhere. A previous admission is a historical comparator, not a randomized concurrent control. The circumstances of the earlier and intervention admissions may differ, and the registry record does not report details to assess comparability. A within-participant comparison can reduce the influence of characteristics that are stable over time, but it cannot by itself separate an intervention-associated change from other changes between admissions. The record also states that masking was none, and that the study was a convenience sample.
The registry describes hyperbaric oxygen therapy as 1-3 sessions depending on response. Thus, treatment exposure could vary according to the registry’s description. The record does not report the number of sessions actually received, or results by exposure. It also does not report the values from the visual analog pain assessments or the hospital length-of-stay outcome. The listed study status is completed, but completion status does not supply the missing outcome estimates.
The safety record lists 8 participants at risk for serious adverse events, 0 with a serious adverse event, and 0 deaths. These are observed counts in the registry record. They do not establish that serious events cannot occur, and the record does not report an uncertainty interval or further safety analysis. The terms listed for serious adverse events are empty.
In general, an estimate describes the observed size and direction of a contrast, while a confidence interval describes the range of values compatible with the data under a stated statistical procedure. Neither an estimate nor its precision can be evaluated for the primary outcome from the registry information because those results are not reported. The findings should therefore be read as an incomplete statistical record of a completed preliminary study, not as a quantified comparison of treatment and prior-admission outcomes.
9. Statistical Methods Explained
The registry identifies the study as single group, with allocation recorded as NA and masking listed as none. It describes a convenience sample and a comparison between an intervention admission and a previous hospital admission for each participant. This is a within-participant historical comparison, not a randomized comparison between concurrent arms. The distinction matters because the observed contrast can reflect differences between admissions as well as any change associated with the intervention. The registry record does not report an analysis plan that addresses those possible differences.
What does a within-participant comparison estimate?
In general, a within-participant comparison examines how an outcome differs between observations from the same person. This can reduce the effect of personal characteristics that are relatively stable across the observations. It does not control automatically for characteristics or circumstances that change over time. In this study, the primary outcome description compares analgesic use during a hyperbaric oxygen admission with use during a previous admission. The record does not report the interval between admissions, whether the admissions were similar in severity, or how differences in care were handled. The comparison should therefore be understood as the registry describes it, without assuming that prior and intervention admissions are exchangeable.
Why report a median and inter-quartile range?
In general, the median is a measure of location based on the ordered observations, and the inter-quartile range describes the spread of the central portion of those observations. These summaries can be informative for measurements with skewed distributions or influential extreme values. The registry specifies these summaries for analgesic use in MME. It does not report the observed median or inter-quartile range, nor does it describe a test or model used to compare the admission measurements.
What is over-dispersion, in general?
In general, over-dispersion occurs when observed variability is greater than a statistical model expects. When a model fails to account for excess variability, its uncertainty estimates can be too small, making results appear more precise than warranted. Whether this issue applies depends on the outcome and the analysis. The registry record does not report a statistical model for the primary endpoint, a dispersion assessment, or an adjustment for over-dispersion. No claim about its presence or absence can be made for this study from the registry record.
How should an estimate and confidence interval be read?
In general, an estimate gives the observed value of a quantity, such as a difference between outcomes. A confidence interval expresses uncertainty around an estimate under the assumptions of a specified method. A narrow interval indicates greater precision than a wide interval, but neither the interval nor the estimate alone resolves design limitations such as a historical comparator. The registry record does not report an effect estimate or confidence interval for the primary endpoint. A statistical significance result is also not reported in the registry record.
What can planning calculations say?
In general, sample-size calculations illustrate how many participants might be needed under stated assumptions about an effect, variability, significance level, allocation, and analysis method. Such calculations are planning illustrations, not observed results and not evidence that a completed study had a particular probability of detecting an effect. The registry description of the planning assumptions refers to an assumed fraction of an observed effect, equal allocation between arms, a two-sided significance level of 0.05, and a normal approximation. It distinguishes participants per arm for non-time-to-event outcomes from total events for time-to-event outcomes. The registry record does not report an actual sample-size justification for this trial, and the study itself is identified as single group. Any planning illustration should not be confused with the trial’s observed enrollment or an analysis result.
The registry lists 2 outcome measures and 0 analyses. It does not report how the primary endpoint was analyzed, how repeated or paired measurements were handled, or what statistical method was used for the secondary outcome. The record also does not report a prespecified multiplicity procedure, missing-data method, or analysis population definition. Without those details and without outcome estimates, the statistical evidence cannot be reconstructed from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 2 outcome measures and 0 analyses. It identifies analgesic use in MME as the primary outcome and hospital length of stay as a secondary outcome; the summary also describes participant self-assessment of pain using a visual analog scale before and after treatment. The record does not report how these measures were organized into the listed outcome-measure count, which results were analyzed, or whether any multiplicity adjustment was planned or used. A multiplicity procedure is not reported in the registry record.
In general, when several outcomes or comparisons are examined, the chance of finding at least one apparently notable result can increase. Statistical approaches can address this issue, but the appropriate approach depends on the analysis plan and the questions being tested. No inferential results are reported, so the impact of multiplicity cannot be evaluated.
The record does not report missing-data counts, reasons for missingness, or a method for handling missing observations. It also does not define analysis populations, such as which participants were included in each outcome analysis. Although enrollment is recorded as 8, that figure alone does not establish how many participants contributed data to any particular endpoint. The registry record does not report endpoint-specific denominators or participant-level completeness. It would therefore be inappropriate to assume that all enrolled participants had complete outcome data or were included in an analysis.
The record also does not report a statistical analysis plan, a missing-data sensitivity analysis, or details about how the previous-admission comparison would be constructed if one of the paired observations were unavailable. These omissions limit assessment of both the analysis population and the robustness of any potential result.
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 |
|---|---|---|---|
| Treatment | 0 | 8 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment | 0 of 8 |
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 |
|---|---|
| Treatment | 0 of 8 |
The serious adverse event record lists the Treatment group with 8 participants at risk, 0 participants affected by a serious adverse event, and 0 deaths. No serious adverse event terms are listed. These figures describe the safety entries in the registry record; they do not provide a comparative estimate against a concurrent control group. The study is identified as single group, and no control-group safety results are listed.
In general, an observed count of zero means that no event was recorded in the observed group during the period captured by the record. It does not show that the underlying risk is zero. With a small group, uncommon events may not appear in the observed data, and a zero count does not by itself quantify the uncertainty about event risk. No confidence interval or further safety analysis is reported in the registry record.
The registry summary does not specify the observation period or additional details about how adverse events were collected. The recorded absence of listed serious events should therefore be interpreted narrowly: the registry reports 0 serious adverse events and 0 deaths among the 8 listed as at risk. It is not a general conclusion about safety, nor a comparison of risk between treatment and control.
12. What the Result Does, and Does Not, Mean
The registry record describes a completed preliminary study of hyperbaric oxygen therapy in adults presenting with an uncomplicated acute sickle cell pain crisis. It records enrollment of 8 and identifies analgesic use in MME during admission to discharge as the primary outcome. The intended comparison is between an intervention admission and each participant’s previous hospital admission. The record also describes self-assessed pain and lists hospital length of stay as a secondary outcome.
What the record does not provide is the primary outcome result. There is no reported median, inter-quartile range, effect estimate, confidence interval, or statistical test for analgesic use. Results for pain and hospital length of stay are also not reported in the registry record. Consequently, the posted information cannot quantify whether the outcomes differed between the intervention admission and the prior admission, or how precise such a comparison would be.
The design also constrains what any observed change could mean. A historical admission is not a randomized concurrent control, and differences in admission circumstances could influence the comparison. The registry record does not describe a method for addressing such differences. The intervention is described as 1-3 sessions depending on response, but actual treatment exposure is not reported. These features are relevant when interpreting a comparison, even if outcome estimates become available elsewhere.
The safety listing records 0 serious adverse events and 0 deaths among 8 participants at risk. These observed counts do not establish that serious harms are impossible, and the record contains no precision estimate for safety outcomes.
In general, a study’s completion status indicates that its recorded study period has ended; it does not imply that results have been reported. The available registry information supports describing the question, design, and recorded safety counts, but not a numerical conclusion about the primary endpoint or the effects of the intervention.
13. Why This Trial Matters Statistically
This study illustrates why a clear distinction between a study question and a study result is essential. The registry specifies an intended comparison of analgesic use in MME during an intervention admission and a participant’s previous admission. Yet it does not report the values needed to quantify that comparison. Knowing the endpoint and the design is not a substitute for an estimate, its uncertainty, and a description of the analysis.
The single-group, within-participant structure also highlights an important design issue. Repeated observations from the same person can be informative, but a previous admission is not automatically a suitable control for a later admission. The design can reduce some stable between-person differences, while leaving time-varying differences between admissions unresolved. Interpreting such a comparison requires attention to both its paired structure and its historical nature.
The record further demonstrates that outcome descriptions and analysis reporting are distinct. It describes analgesic use, pain self-assessment, and hospital length of stay, but lists 0 analyses and reports no outcome estimates. Without the analysis methods, missing-data information, and participant-level outcome completeness, readers cannot assess how the intended endpoints were converted into statistical evidence.
Finally, the serious adverse event listing shows why zero observed events must be described as a count rather than as proof of no risk. The record reports 0 serious events and 0 deaths among 8 at risk, but does not provide an uncertainty analysis or a concurrent comparison. Statistically careful interpretation preserves these distinctions: the study’s aim, its recorded design, its observed safety counts, and the absence of reported efficacy outcome estimates are separate parts of the evidence.
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 registry record identifies a convenience sample and records enrollment of 8. The small enrollment limits the amount of information available for characterizing outcomes, but the record does not report a sample-size justification or the assumptions used to choose the enrollment target. The planning assumptions described in the record are not an explanation of the study’s own design and should not be treated as evidence of observed power.
The comparison uses each participant’s previous hospital admission as a control. This historical comparison may be affected by changes between admissions, including differences in the crisis or care. The record does not report details about the prior admissions, their comparability, or adjustment for possible differences. The study is not a randomized comparison, and masking is listed as none.
The registry describes treatment as 1-3 hyperbaric oxygen sessions depending on response, but does not report actual exposure or how response determined the number of sessions. The summary describes pain self-assessment and hospital length of stay, but does not report results for either measure. Primary outcome results are likewise not reported in the registry record.
The record does not report endpoint-specific participant counts, missing-data handling, analysis populations, a statistical analysis plan, multiplicity procedures, or inferential methods. It lists 2 outcome measures and 0 analyses. These gaps prevent assessment of how complete the outcome data were, how comparisons were calculated, and how uncertainty was quantified. The safety listing contains no serious adverse event entries, but no safety confidence interval or detailed observation period is reported. These limitations restrict interpretation of both the intended comparison and the recorded safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Hyperbaric Oxygen Therapy in Sickle Cell Pain — NCT03412045.
- Registry record last updated 2026-07-28; status last verified 2025-06.
- Results first posted 2026-07-28.
- 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 identifies NCT03412045, “Hyperbaric Oxygen Therapy in Sickle Cell Pain,” as a completed, single-group study sponsored by the University of Nebraska. Enrollment is recorded as 8. The start date is 2022-09-01 and the primary completion date is 2025-06-05. Phase and allocation are recorded as NA, and masking is listed as none.
The intervention was hyperbaric oxygen therapy, described as 1-3 sessions depending on response. The primary outcome was total analgesic administered in MME from admission to discharge, summarized by median and inter-quartile range. The stated comparison was with each participant’s previous hospital admission. Hospital length of stay is listed as a secondary outcome, and the summary describes visual analog pain assessment before and after treatment.
The record lists 2 outcome measures and 0 analyses. It does not report primary or secondary outcome results. The serious adverse event listing records 0 affected participants and 0 deaths among 8 at risk.