Unrelated Umbilical Cord Blood (UBC)Transplantation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Unrelated Umbilical Cord Blood (UBC)Transplantation (NCT01768845), a na na study. The primary outcome is Number of Participants With Engraftment.

2. Clinical Question

The clinical context described in the registry summary is the use of umbilical cord blood as a source of hematopoietic progenitor cells for transplantation. The summary notes that donor availability can be an obstacle and describes cord blood as a readily available source, while also noting the limited cell quantity in a cord blood unit. These points explain the rationale for studying the transplant approach; they do not establish its outcomes in this study.

The record also lists overall survival at Day 180 post-transplant as a secondary outcome. A result for that outcome is not reported in the registry record. Neither the primary nor secondary endpoint can be compared with an alternative treatment using the information recorded.

3. Trial Design

This is a completed, single-group clinical study sponsored by West Virginia University. The registry record lists enrollment of 34 and a study start date of 2009-02-03. The primary completion date is 2019-05-14. The phase is recorded as not applicable, allocation as not applicable, and masking as none. These registry entries describe the design classification; they do not provide a detailed protocol or analysis plan.

The study intervention is unrelated umbilical cord blood transplantation. The arm description states that participants receive a preparative regimen followed by one or two umbilical cord blood units. The preparative regimen involves chemotherapy and radiation, and its selection is described as a physician decision. If two products are used, the registry description says they are administered sequentially on the same day. The available arm description is incomplete, so further treatment details are not reported in the registry record.

Because the design is single-group, participants are not assigned to a separate control arm in the registry record. There is no randomized allocation or masking. Consequently, the study record can describe outcomes among the treated group if those results are reported, but it cannot by itself provide a randomized estimate of how outcomes compare with another intervention or with no transplant.

The registry record lists a primary outcome of participants with engraftment within 60 days and a secondary outcome of overall survival at Day 180 post-transplant. It does not report a primary or secondary outcome result. The record lists no analyses. Details such as the intended analysis population, handling of missing observations, and any planned adjustment for differences among participants are not reported in the registry record.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Engraftment, measured over 60 days.

The primary endpoint is the number of participants with engraftment. The registry defines engraftment as neutrophil recovery associated with donor engraftment within the first 60 days after transplant. The timeframe is therefore an early post-transplant period, and the endpoint is recorded as a count of participants rather than as a continuous measurement.

In general, engraftment is used as an early biological outcome in transplantation studies because it captures whether donor-derived blood-forming cells have begun to restore a component of blood-cell production. Neutrophil recovery is the specific recovery feature named in this registry definition. The endpoint does not, on its own, describe longer-term survival, control of the underlying disease, or the full course of recovery.

The registry record does not report how many participants met the endpoint definition. Although enrollment is recorded as 34, the outcome count is not reported in the registry record, and a count or proportion meeting the endpoint cannot be read from the posted results. The record also does not report endpoint-specific missingness, the details of assessment, or how a participant who died or lacked an assessment would be handled in the analysis.

Overall survival at Day 180 post-transplant is listed separately as a secondary outcome, but its result is also not reported in the registry record. The primary endpoint and the secondary outcome address different aspects of the post-transplant course and should not be treated as interchangeable measures.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry record is limited. The design is listed as single-group, the primary endpoint is a participant count, and the record lists no analyses. The primary endpoint result is not reported in the registry record. The concepts below explain how such outcomes are generally analyzed; they do not describe an analysis documented for this study.

What does a participant count represent?

The primary endpoint is the number of participants who meet the stated engraftment definition within 60 days. In general, a count is a direct summary of how many people meet an outcome definition. A count is easier to interpret when its denominator and the rules for including participants are also clear. A count can be converted to a proportion only when the relevant denominator is specified and the numerator is available. Here, the enrollment is recorded as 34, but the engraftment count is not reported in the registry record. An observed proportion therefore cannot be interpreted from the posted results.

Counts also depend on clear outcome ascertainment. In general, the analysis should state how the endpoint is assessed, how the time window is applied, and what happens when an outcome is not assessed. The registry record defines engraftment in terms of neutrophil recovery associated with donor engraftment within 60 days, but details of assessment and missing-outcome handling are not reported in the registry record.

What would an uncertainty interval mean?

In general, a confidence interval expresses the range of values reasonably compatible with the observed data under a specified statistical model and procedure. It conveys precision as well as the point estimate: a narrower interval indicates greater precision under that method, while a wider interval indicates less precision. An interval does not guarantee that the true value lies within its limits, and it does not correct for bias in study design or measurement.

No confidence interval for engraftment is reported in the registry record. Because the primary outcome count is also absent, there is no posted estimate whose precision can be assessed. A confidence interval should not be inferred from enrollment alone.

Why does the single-group design matter?

In general, a single-group study can report outcomes observed after an intervention, but it lacks a concurrent comparison group for estimating a treatment contrast. Changes over time or outcomes after treatment may reflect the intervention, participant characteristics, the underlying condition, other care, or chance. Random allocation in a comparative study can help balance measured and unmeasured factors on average; this record does not describe random allocation or a comparison arm.

Accordingly, the record does not support a comparative effect estimate. It also does not document a statistical adjustment that could address differences between groups, since there is no second group listed and no analyses are recorded.

What do the planning assumptions describe?

The registry-associated sample-size assumptions describe planning illustrations, not the original trial design. They specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. For time-to-event illustrations, the assumptions describe a total event count; for other illustrations, they describe participants per arm.

These assumptions are hypothetical planning choices. They do not show that this single-group study used two arms, nor do they establish that the trial was designed around those assumptions. Planning sample sizes are not observed results and are not observed power. The registry record does not report a sample-size justification for the actual study or a statistical plan explaining a target effect and analysis.

In general, a planning calculation depends on its assumptions, including the outcome model, allocation, significance level, target power, and effect to detect. When the assumptions differ from the actual study design or outcome, a planning illustration cannot be read as a direct description of the study's evidential strength. No numerical planning result is interpreted because the registry record does not give a trial-specific statistical analysis to connect with such a calculation.

What can be inferred from the safety fields?

The safety fields list participants at risk, serious adverse events, other adverse events, deaths, and a serious adverse event term. Such summaries are generally descriptive. Their interpretation depends on the definitions of an event, the period of observation, event attribution, and the denominator used for each summary. Those details are not reported in the registry record. The recorded values should not be treated as a comparative safety estimate, because there is no separate control group.

In short, standard statistical tools could summarize an endpoint count and its uncertainty if the outcome data and analysis details were available. The registry record does not report the primary outcome count, an uncertainty interval, inferential analyses, or an analysis population. General statistical concepts therefore clarify what information would be needed, but they cannot fill in the missing study results.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Transplant")
n      <- c(34)
events <- c(29)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Transplant  34  29  85.3  68.9  95.0  69.9  93.6  69.7  93.4

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome, participants with engraftment within 60 days, and one secondary outcome, overall survival at Day 180 post-transplant. It lists no analyses. Results for either outcome are not reported in the registry record.

Multiplicity refers, in general, to the increased chance of at least one apparently unusual result when several hypotheses or outcomes are tested. Study protocols may address this by identifying a primary outcome, setting a hierarchy, or adjusting inference across tests. The registry record does not report a multiplicity strategy, a testing hierarchy beyond naming primary and secondary outcomes, or any inferential results. It is therefore not possible to determine how multiplicity was handled.

Missing data can affect an outcome estimate when some participants lack an assessment or when loss of follow-up is related to the outcome. In general, transparent reporting describes the amount and reasons for missingness and the method used to handle it. The registry record does not report missing outcome data, follow-up completeness, or a missing-data method. The absence of those details does not imply that all assessments were complete.

The record does not identify analysis populations, such as which participants were included in an endpoint analysis or whether inclusion depended on treatment received or outcome availability. Enrollment is recorded as 34, but the endpoint analysis denominator is not reported in the registry record. It is therefore not possible to determine whether the primary endpoint was analyzed in all enrolled participants or another population.

These omissions limit both reproducibility and interpretation. They leave uncertainty about the analysis choices that would be needed to connect the endpoint definition to an estimate. No specific missing-data or multiplicity procedure should be attributed to this study based on the registry record.

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 serious adverse event terms

Serious events with the highest arm-level rate: infection (2.9%).

The registry safety fields list a Transplant group with 34 participants at risk for serious adverse events and 1 affected. The corresponding fields for other adverse events list 34 at risk and 0 affected. Infection appears among the serious adverse event terms at 2.9%. These are the safety values recorded, not a comparative estimate against another group.

The death count is listed as 21. The registry record does not report the time period represented by this field, whether deaths were considered related to transplantation, or how deaths relate to the adverse event summaries. The denominator basis for the infection percentage is also not reported in the registry record. No timing or severity detail beyond the serious-event classification and listed term is posted by the record.

In general, adverse event summaries depend on consistent definitions, duration of observation, and clear attribution rules. A count or percentage alone does not establish cause, and a single-group summary cannot show how event frequency compares with another treatment. The listed safety figures should therefore be interpreted narrowly as registry-recorded descriptive information, not as a complete assessment of safety or a causal conclusion.

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

The registry record establishes that this was a completed, single-group study of unrelated umbilical cord blood transplantation, with enrollment recorded as 34. It specifies a primary endpoint based on engraftment within 60 days and lists overall survival at Day 180 post-transplant as a secondary outcome. These design details explain what outcomes the study was intended to address.

The record does not report the result for either outcome. It therefore does not provide an observed engraftment count or rate, a Day 180 survival estimate, or statistical uncertainty around either outcome. It is not possible to use the posted results to judge how frequently engraftment occurred in the study group or to quantify the precision of that outcome.

The single-group design also sets a boundary on interpretation. Without a separate comparison group, outcomes cannot be attributed to transplantation by comparing participants with a control group in this record. Even a reported outcome would be descriptive of the observed group rather than a randomized estimate of a treatment difference.

The safety fields report one serious adverse event, no other adverse event in the listed group fields, infection among serious terms at 2.9%, and 21 deaths. The observation window, attribution, and denominator basis for some fields are not reported in the registry record. These figures cannot establish the cause of events or provide a comparison with another intervention.

These limitations do not show that the intervention had no effect, nor do they show that it had a particular effect. They describe what can and cannot be concluded from the registry information: the study question and endpoint definitions are recorded, while key outcome results and analysis details are absent. Any conclusion about effectiveness, comparative benefit, or comparative safety would go beyond the information reported.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between a clinical question and the evidence needed to answer it. The registry specifies a treatment approach, a single-group design, and a clearly framed early outcome: engraftment within 60 days. These features tell readers what was studied and what the primary endpoint was meant to capture.

For interpretation, however, an endpoint definition is not an outcome result. The record does not report the number of participants who met the engraftment definition, an uncertainty interval, or an analysis. Without those elements, readers cannot assess the observed frequency or its precision. An enrollment figure does not substitute for an endpoint estimate.

The single-group structure is also important. It makes the distinction between describing outcomes and estimating comparative effects especially clear. A control group and suitable allocation would be needed to make a direct randomized comparison; neither is listed in this record. Statistical methods cannot create a comparison that the design does not contain.

The record further illustrates why outcome reporting needs context. Safety counts and a listed infection percentage are difficult to interpret fully without follow-up duration, event definitions, attribution, and denominator details. Similarly, a secondary outcome label does not convey its result. Transparent reporting of estimates, uncertainty, analysis populations, and missing data would make the findings more reproducible and useful for statistical interpretation.

The main statistical lesson is therefore about evidence boundaries. Registry descriptions can establish the intended question and design, but absent results cannot be reconstructed from enrollment or safety entries. Clear separation of reported results, missing information, and general statistical principles helps prevent unsupported comparative or causal conclusions.

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.

A central limitation is that the registry record does not report the primary endpoint result. The number of participants with engraftment within 60 days is not stated, so the outcome cannot be quantified from the posted results. A result for overall survival at Day 180 post-transplant is also not reported.

The single-group design provides no concurrent control comparison. The record therefore cannot support a randomized treatment contrast, and its design does not isolate treatment effects from other influences on outcomes. Allocation is listed as not applicable and masking as none.

Important analysis details are not reported in the registry record. These include the statistical analysis plan, analysis population, endpoint-specific denominator, missing-data handling, and any multiplicity approach. The record lists no analyses. It also does not report a sample-size justification for the study, so the planning assumptions associated with sample-size illustrations should not be mistaken for the original design rationale.

The safety entries are limited by unreported context. The time period and attribution for the death count are not stated, and the denominator basis for the infection percentage is not reported in the registry record. The available fields do not provide the timing or detailed course of adverse events.

The registry summary and arm description are incomplete, and detailed eligibility criteria, participant characteristics, and full treatment procedures are not reported in the registry record. These omissions limit assessment of who was studied, how consistently the intervention was delivered, and how the recorded outcomes should be interpreted. The limitations concern the available registry information and should not be taken as proof that details were not collected elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Unrelated Umbilical Cord Blood (UBC)Transplantation — NCT01768845.
• Registry record last updated 2021-06-14; status last verified 2021-06.
• Results first posted 2021-06-08.
• 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

The registry record describes a completed, single-group study sponsored by West Virginia University, with enrollment recorded as 34. The study start date is 2009-02-03, and the primary completion date is 2019-05-14. Phase and allocation are listed as not applicable, and masking is listed as none.

The intervention is unrelated umbilical cord blood transplantation following a physician-selected preparative regimen. The primary outcome is the number of participants with engraftment within 60 days, defined by neutrophil recovery associated with donor engraftment. Overall survival at Day 180 post-transplant is listed as a secondary outcome.

Neither outcome result is reported in the registry record, and no analyses are listed. Safety fields record one serious adverse event, no other adverse events in the group fields, infection at 2.9% among listed serious terms, and 21 deaths. Context for the death count and infection percentage is not reported in the registry record.