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 Effects of Transfusion of Older Stored Red Cells (NCT01534676), a non-randomized na study. The primary outcome is Non-transferrin-bound Iron Level.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01534676 |
| Phase | NA |
| Condition | Sickle Cell Disease, Thalassemia |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Columbia University |
| Results posted | Yes |
2. Clinical Question
Population
The intended participants were recipients with sickle cell disease or thalassemia who were chronically transfused. The record describes transfusions as occurring according to each recipient’s chronic transfusion schedule. Three participants were enrolled, but the study closed due to poor enrollment; enrolled participants were never randomized or transfused on study.
Intervention
The planned transfusion conditions included fresh blood less than 14 days old, stored blood more than 28 days old, cryopreserved blood, and washed stored blood. The descriptions also distinguish whether recipients were on or off chelation therapy. These are descriptions of intended study conditions, not evidence that any of these transfusions occurred in the study.
Comparator
The planned conditions could have allowed observations across blood-storage and processing approaches, with chelation status also described. However, allocation was non-randomized, masking was absent, and the registry categorizes the model as single-group. It specifically notes that the arms are not a like-for-like control comparison. No completed comparison between transfusion conditions is reported.
Primary question
The primary endpoint was non-transferrin-bound iron measured 2 hours after transfusion. The intended question was whether transfusion conditions were associated with a change in this iron measure, in the context of the study’s interest in iron and inflammation. The registry also describes aims concerning chelation, washing, and cryopreservation. Because no study transfusion or outcome data were collected or analyzed, the record cannot answer whether these conditions differed.
3. Trial Design
This was a non-randomized study with no masking and a registry model designation of single group. The record lists planned transfusion conditions involving fresh, stored, cryopreserved, and washed blood, as well as chelation status. That list describes the intended study structure; it does not establish that participants received those interventions. The record states that enrolled participants were never randomized or transfused on study because the study closed due to poor enrollment.
Three participants were enrolled. The study status is terminated. The recorded start was 2012-02, and primary completion was 2013-03. The phase is listed as NA. The record identifies sickle cell disease and thalassemia as the conditions under study. Columbia University is listed as the sponsor.
The intended transfusion descriptions specify one or two units according to a chronic transfusion schedule. Fresh blood was described as less than 14 days old; stored blood was described as more than 28 days old. Cryopreserved blood could be fresh or old, and the washed-blood description refers to fresh or old stored blood more than 28 days old. Chelation status differs across the descriptions. These details belong to the planned intervention descriptions, not to a record of completed treatment.
Non-randomized allocation means that assignment was not by chance. In general, when groups are not randomized, differences between them can reflect participant characteristics or other factors as well as the intervention. Here, however, the central limitation is even more direct: there are no study transfusions, measurements, or analyses to compare. The record also cautions that the planned arms are not a like-for-like control comparison. The protocol details, including any further design rationale or allocation procedures, 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.
Before assignment: Enrolled participants (recipients) were never randomized or received transfusion on study because study closed due to poor enrollment.
Overall Study
| Stage | Recipients | Donors |
|---|---|---|
| STARTED | 2 | 1 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 2 | 1 |
Reasons for not completing this period:
| Reason | Recipients | Donors |
|---|---|---|
| Study closed due to poor enrollment | 2 | 1 |
Analysis population for the primary outcome, as defined in the registry: Enrolled participants (recipients) were never randomized or received transfusion on study because study closed due to poor enrollment. No data was collected or analyzed.
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 | Recipients | Donors | Total |
|---|---|---|---|---|
| Participants analysed | 2 | 1 | 3 | |
| Age, Categorical: <=18 years | Participants | 2 | 0 | 2 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 1 | 1 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 1 | 1 |
| Sex: Female, Male: Male | Participants | 2 | 0 | 2 |
| Region of Enrollment: United States | participants | 2 | 1 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Non-transferrin-bound Iron Level, measured over 2 hours after transfusion.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was non-transferrin-bound iron level, with measurement planned 2 hours after transfusion. Non-transferrin-bound iron refers to iron not carried by transferrin, the protein that transports iron in the blood. This measure is relevant to a study focused on iron and inflammation because it concerns circulating iron outside that usual transport binding.
In general, an endpoint is a specified outcome used to assess a study question. A measurement at a defined time after an intervention can be used to examine whether the outcome is associated with the intervention over that interval. The selected timing makes the intended assessment an early post-transfusion measurement; it does not describe longer-term effects. The registry does not report a more detailed endpoint rationale, assay method, units, or a threshold for interpreting the value.
No endpoint values were collected or analyzed in this study. Consequently, there is no reported baseline level, post-transfusion level, change, group contrast, or estimate of precision. The endpoint’s selection explains what the study intended to measure, but it cannot establish an observed response or any association between transfusion conditions and iron levels.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record contains no primary-outcome results. Although non-transferrin-bound iron was designated as the primary endpoint and measurement was planned 2 hours after transfusion, no participant received a transfusion on study and no data were collected or analyzed. Therefore, there is no observed endpoint value or treatment-effect estimate to interpret.
The planned intervention descriptions refer to fresh blood less than 14 days old, stored blood more than 28 days old, cryopreserved blood, and washed blood, with chelation status described for the conditions. Those descriptions do not constitute findings. The record does not show whether any of the conditions changed non-transferrin-bound iron, whether changes differed by condition, or whether chelation, washing, or cryopreservation was associated with an outcome.
There is also no inferential result: the record lists zero analyses. No confidence interval, p-value, adjusted estimate, or unadjusted estimate is reported. A confidence interval would ordinarily indicate the range of effect sizes reasonably compatible with the observed data under the analysis assumptions. Without measured outcome data and an analysis, neither an estimate nor its precision can be assessed. The registry does not report a statistical analysis plan or explain what model would have been used.
The enrollment of three participants is a study-completion fact, not a basis for estimating an effect. Enrollment alone does not tell how an outcome would have varied, whether groups would have been comparable, or how precisely an effect could be estimated. In particular, the record states that no one was randomized or transfused on study, so the planned intervention conditions cannot be treated as observed exposure groups.
The adverse-event figures are limited to the recorded event-group counts and should not be mistaken for the primary endpoint results. They report no affected participants in the listed serious or other adverse-event categories, but the record does not provide study transfusion exposure or primary outcome data. Thus, the registry supports a description of an incomplete study and its intended question, not a conclusion about the effects of any transfusion approach.
9. Statistical Methods Explained
What the design labels mean. The registry classifies allocation as non-randomized, masking as none, and the model as single group. In general, randomization assigns participants by chance and can help balance measured and unmeasured characteristics across comparison groups. Non-randomized allocation does not provide that protection. Masking means keeping some people involved in a study unaware of assigned treatment; the record lists no masking. These design labels describe the planned study, but they do not imply that the planned treatments or measurements were completed.
The record also lists multiple planned transfusion descriptions while identifying the model as single group. It cautions that the arms are not a like-for-like control comparison. A statistical comparison of groups is most interpretable when the groups represent comparable participants and differ in the exposure of interest. Non-randomized groups may differ in other ways, so even completed comparisons could require careful interpretation. In this study, no such comparison can be made because no on-study transfusions or endpoint data were recorded.
Endpoint and timing. The endpoint was non-transferrin-bound iron level measured 2 hours after transfusion. In general, a prespecified endpoint gives a study a defined outcome to assess, and a defined measurement time clarifies when that outcome is evaluated. Here, the record identifies the intended endpoint and timing but reports no measured values, units, assay details, or data analysis. The detailed measurement procedures are not reported in the registry record.
Estimation and uncertainty. An effect estimate describes the size and direction of an outcome contrast or change. A confidence interval communicates uncertainty around an estimate: narrower intervals indicate greater precision under the assumptions of the method, while wider intervals indicate less precision. A p-value, when used, summarizes how unusual data would be under a specified null hypothesis and analysis model; it is not itself a measure of effect size or clinical importance. None of these results is reported because the registry states that no data were collected or analyzed. The analysis method and any inferential procedure are not reported in the registry record.
Why comparison structure matters. A treatment contrast requires defined observations under the conditions being compared. The planned descriptions include fresh blood less than 14 days old, stored blood more than 28 days old, cryopreserved blood, and washed blood, with chelation status also described. But a planned intervention is not an observed intervention. Since participants were never transfused on study, there are no outcome records under these conditions to contrast. The non-randomized allocation and lack of a like-for-like control comparison would also have required caution in interpreting any hypothetical group differences.
Sample-size illustrations. The registry describes a planning illustration based on a stated fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such a calculation is a planning exercise, not a measure of the probability that a completed study found an effect. Participants per arm for a chosen power are not observed sample sizes or evidence of an observed result. No observed primary endpoint effect is reported in this study, and no numerical planning estimate is stated in the registry record. The calculation’s inputs and output values therefore cannot establish what the study would have detected.
Over-dispersion and model choice. General statistical note: over-dispersion occurs when outcome variability exceeds what a chosen model expects. When present, it can make standard errors and confidence intervals too optimistic unless the analysis accounts for the extra variability. The registry record does not report a fitted model, a variance assessment, or any finding of over-dispersion; therefore, this concept cannot be applied as a study result. More broadly, model choice depends on the outcome’s form and the design, and the analysis plan is not reported in the registry record.
What can be concluded from the statistical record. The record lists one primary outcome measure and zero analyses. It reports no effect estimate, uncertainty interval, hypothesis test, or model diagnostics. These absences are consistent with the explicit statement that no data were collected or analyzed after the study closed due to poor enrollment. Statistical interpretation should therefore remain descriptive: the study registered a question and planned measurements, but it generated no reported estimate addressing that question.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity concerns the risk of misleading results when multiple outcomes, time points, subgroups, or comparisons are tested. In general, performing many tests can increase the chance of finding an apparently unusual result even when there is no true effect. Study plans may address this by defining a primary outcome, setting a testing hierarchy, or adjusting inference. The registry identifies one primary outcome measure, non-transferrin-bound iron level at 2 hours after transfusion. A multiplicity adjustment or testing hierarchy is not reported in the registry record. Since there were no analyses, the record contains no actual set of tests for which multiplicity can be assessed.
Missing data are also central to interpretation. The primary outcome was not merely partially observed: the record says no data were collected or analyzed because no participants received a transfusion on study. Thus, there are no endpoint values from which to estimate an effect, and no reported missing-data method can recover such an estimate. The reason for the absence of outcome data is described as study closure due to poor enrollment, rather than a reported pattern of missed measurements after treatment.
The registry does not report analysis populations such as an intention-to-treat or per-protocol population, nor does it describe participant flow beyond enrollment and the statement that no one was randomized or transfused on study. Any further definition of an analysis set, handling of incomplete records, or sensitivity analysis is not reported in the registry record. With no outcome observations or analyses, there is no basis for judging whether exclusions or missing-data assumptions affected a treatment estimate.
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 |
|---|---|---|---|
| Recipients | 0 | 2 | 0.0% |
| Donors | 0 | 1 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Recipients | 0 of 2 |
| Donors | 0 of 1 |
The registry lists recipients and donors as separate event groups. For recipients, 2 were listed as at risk for serious adverse events and 0 as affected; 2 were listed as at risk for other adverse events and 0 as affected. For donors, 1 was listed as at risk for serious adverse events and 0 as affected; 1 was listed as at risk for other adverse events and 0 as affected. Death counts are not reported in the registry record.
These figures should be read as the adverse-event counts recorded for those groups, not as evidence that transfusion-related risk was absent. The record says that participants were never transfused on study, and the study collected no primary outcome data. It does not explain the relationship between the event-group counts and the enrolled participant count, nor does it report event definitions, event types, follow-up duration, or detailed ascertainment procedures. The listed zero affected counts indicate that no affected participants are recorded in these categories; they do not establish safety under the planned transfusion conditions.
No serious adverse-event terms are listed. The figures are descriptive registry entries and cannot support a comparative safety analysis because no completed treatment comparison or study transfusion exposure is reported.
12. What the Result Does, and Does Not, Mean
The main result is the absence of an analyzable primary endpoint, not a measured difference between transfusion conditions. The study intended to assess non-transferrin-bound iron 2 hours after transfusion, but the registry states that no participants received a transfusion on study and no data were collected or analyzed. There is therefore no estimate of what happened to the endpoint.
This record does not show that fresh blood, stored blood, cryopreserved blood, washed blood, or chelation was associated with a particular iron response. It also does not establish that the conditions were equivalent. Equivalence requires data and an analysis capable of evaluating whether differences are sufficiently small under a defined criterion; neither is reported. Likewise, the lack of an observed result is not evidence for or against a treatment effect.
The study’s non-randomized allocation and the registry’s warning that the arms are not like-for-like comparisons would have constrained causal interpretation even if outcome data had been collected. Differences between groups in a non-randomized study may reflect factors other than the intervention. But the immediate limitation is that there were no study exposures or measurements to analyze.
Enrollment of three participants and termination due to poor enrollment describe the study’s progress, not its efficacy or safety. The record’s adverse-event counts also do not establish the safety of a transfusion condition, since the record reports no study transfusions and does not provide a comparative safety analysis. The appropriate interpretation is that the registered research question remains unanswered by the posted results.
13. Why This Trial Matters Statistically
This study is statistically instructive because it distinguishes a registered research question from evidence addressing that question. The record defines a primary endpoint and describes several planned transfusion conditions, but enrollment and completion details show that the study did not proceed to on-study transfusion or outcome analysis. A well-specified outcome is useful for planning, yet it cannot substitute for observed data.
The design labels also illustrate why the comparison structure matters. Non-randomized allocation does not ensure comparable groups, and the record explicitly cautions that the planned arms are not a like-for-like control comparison. If comparisons had been completed, interpretation would have needed to account for that design limitation. Here, there is no comparison at all because the planned exposures and measurements were not carried out on study.
The absence of an effect estimate is different from a null finding. A null finding would still arise from observed data analyzed under a defined method; this record reports no data collected or analyzed. As a result, it cannot tell readers whether the estimated effect would have been large or small, or whether it would have been precise or uncertain.
The record also emphasizes the importance of reading safety counts in context. Event counts without study transfusion exposure, detailed follow-up, and a completed comparison do not answer whether one transfusion approach is safer than another. Overall, this is a case where the registry documents aims and planned methods, while the terminated study leaves the statistical question unresolved.
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 is that the study closed due to poor enrollment before any on-study transfusions occurred. The registry reports three enrolled participants but states that none were randomized or received a transfusion on study. No data were collected or analyzed, so the primary endpoint has no reported observations.
The intended comparisons also have design constraints. Allocation was non-randomized, masking was absent, and the record classifies the model as single group. It further cautions that the listed arms are not a like-for-like control comparison. These features would complicate interpretation of any between-condition differences; in the actual record, no such differences can be estimated.
The registry lists planned conditions involving blood storage age, cryopreservation, washing, and chelation status, but none is reported as an administered study intervention. Thus, the intervention descriptions should not be treated as completed exposure data. The record does not report the assay method, outcome units, detailed statistical plan, analysis populations, missing-data procedures, or multiplicity approach. These details are not reported in the registry record.
The adverse-event entries are limited. The record gives at-risk and affected counts for recipients and donors, but does not report deaths, event terms, follow-up duration, event definitions, or an analysis of safety by transfusion condition. With no on-study transfusions, those entries cannot establish comparative safety. Finally, no numeric treatment-effect or precision estimate is reported; the registry therefore offers no basis for assessing the magnitude or uncertainty of an effect on non-transferrin-bound iron.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Transfusion of Older Stored Red Cells — NCT01534676.
- Registry record last updated 2016-10-05; status last verified 2016-08.
- Results first posted 2016-10-05.
- 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
NCT01534676, “Effects of Transfusion of Older Stored Red Cells,” was a non-randomized study with no masking and a single-group model designation. It enrolled three participants and was terminated after closure due to poor enrollment. The listed conditions were sickle cell disease and thalassemia.
The planned study concerned transfusion of fresh, stored, cryopreserved, or washed blood, with chelation status described in the intervention plans. The primary endpoint was non-transferrin-bound iron level 2 hours after transfusion. The registry states that participants were never randomized or transfused on study and that no data were collected or analyzed. It lists zero analyses and no primary endpoint results. The record therefore documents the intended question but does not provide an estimate of the effect of any transfusion condition.