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 Microvascular Blood Flow in Sickle Cell Anemia (NCT01566890), a non-randomized na study. The primary outcome is Microvascular Blood Flow Rate Change.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01566890 |
| Phase | NA |
| Condition | Sickle Cell Disease, Sickle Cell Anemia |
| Allocation | Non-Randomized |
| Design model | Sequential |
| Masking | None (open label) |
| Enrollment | 91 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Versiti Blood Health |
| Results posted | Yes |
2. Clinical Question
Population
The primary endpoint description identifies adults with sickle cell anemia who received regadenoson and a sickle cell control group. The endpoint population is reported as 20 participants in the Regadenoson arm and 6 participants in the Sickle Cell Controls arm. The registry also describes healthy control participants, but they are not part of the primary endpoint comparison described.
Intervention
Regadenoson infusion alongside contrast-enhanced ultrasound (CEUS). The study is concerned with whether CEUS can measure changes in skeletal muscle microvascular blood flow around the infusion.
Comparator
The Sickle Cell Controls arm received CEUS without the regadenoson infusion, according to its arm description. The study is non-randomized, so this is not a randomized comparison.
Primary question
How does the ratio of microvascular blood flow at 24 hours compared with baseline behave in participants receiving regadenoson, and how does it compare with the sickle cell control group? The registry describes a 40% increase as the stated primary outcome target, but the numerical endpoint result is not reported in the registry record.
The biological and measurement questions are related but distinct. Regadenoson is the intervention under study, while CEUS is the measurement technique used to assess blood flow. The registry’s background describes CEUS as a way to detect flow in small blood vessels and frames its feasibility for assessing blood-flow changes in sickle cell disease as a hypothesis. The primary outcome uses a ratio of change in skeletal muscle microvascular blood flow, defined as volume multiplied by velocity, between baseline and 24 hours.
The question is not whether the study establishes a clinical benefit. It is whether the posted endpoint data show a change in the measured blood-flow ratio in the regadenoson arm, and how that observation compares with the sickle cell controls. Because the endpoint estimate and its uncertainty are not reported in the registry record, the direction, size, and precision of any observed difference cannot be described from this record. The non-randomized design also means that the comparison cannot be interpreted as if participants had been assigned to groups at random.
3. Trial Design
This completed study, NCT01566890, is titled “Microvascular Blood Flow in Sickle Cell Anemia.” It is recorded as a non-randomized, unmasked, sequential study, with an enrollment of 91. The phase is recorded as NA. The registry lists a study start of 2012-07 and a primary completion date of 2019-07-05. The sponsor is Versiti Blood Health.
The record describes several arms: Regadenoson ARM, Sickle Cell Controls ARM, Sickle Cell CEU ARM, Healthy Control ARM, and Technique Optimization Controls. The Regadenoson arm description says adult subjects with sickle cell anemia received a regadenoson infusion with CEUS. The Sickle Cell Controls and Sickle Cell CEU descriptions say adult subjects with sickle cell anemia received CEUS. Healthy Control participants are described as healthy African American control subjects without sickle cell anemia, and Technique Optimization Controls as healthy volunteers undergoing CEUS. These groups have different stated roles; the record does not establish that they are interchangeable comparison groups.
For the primary endpoint, the registry identifies 20 participants in the Regadenoson arm and 6 participants as sickle cell controls. It explicitly excludes the Sickle Cell Crisis arm from that endpoint because it was not measured by CEUS in a similar timeframe. The registry describes measurements at baseline and 24 hours for the primary comparison. Further details about how participants entered each arm, the sequence of enrollment, or whether eligibility and measurement procedures differed by group are not reported in the registry record.
Non-random allocation and no masking are important features when interpreting the groups. Without random assignment, differences between groups may reflect participant characteristics or other factors as well as the intervention. The record does not report a protocol-level statistical plan, sample-size justification, interim analysis plan, or further detail about the sequential model.
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 | Regadenoson ARM | Sickle Cell Controls ARM | Sickle Cell Crisis ARM | Healthy Controls | Technique Optimization Controls |
|---|---|---|---|---|---|
| STARTED | 32 | 10 | 21 | 21 | 7 |
| COMPLETED | 21 | 6 | 10 | 7 | 0 |
| NOT COMPLETED | 11 | 4 | 11 | 14 | 7 |
Reasons for not completing this period:
| Reason | Regadenoson ARM | Sickle Cell Controls ARM | Sickle Cell Crisis ARM | Healthy Controls | Technique Optimization Controls |
|---|---|---|---|---|---|
| Adverse Event | 1 | 0 | 0 | 0 | 0 |
| Withdrawal by Subject | 3 | 1 | 1 | 1 | 0 |
| Screen failure | 6 | 0 | 1 | 1 | 0 |
| Incomplete CEU data | 1 | 3 | 5 | 8 | 0 |
| Lost to Follow-up | 0 | 0 | 4 | 4 | 0 |
| Other | 0 | 0 | 0 | 0 | 7 |
Analysis population for the primary outcome, as defined in the registry: There were 20 participants in the Regadenoson arm, and 6 participants acted as sickle cell controls. Sickle Cell Crisis ARM is not included because arm was not measured by CEUS in a similar timeframe as Regadenoson ARM and Sickle Cell Controls ARM, as indicated in Results Baseline Characteristics Arm/Group Description for Sickle Cell Crisis ARM.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: For this study, baseline measures of heart rate and blood pressure were taken 5-10 minutes apart, prior to drug administration and/or (in control groups) a contrast enhanced ultrasound was performed. Baseline was defined as the subject doing well, reporting no more than baseline pain, and being at least 2 weeks from a hospitalization or emergency department visit. Healthy Controls and Technique Optimization Controls are not listed as these groups were intended to determine intravariability.
| Characteristic | Unit | Regadenoson ARM | Sickle Cell Controls ARM | Sickle Cell Crisis ARM | Healthy Controls | Technique Optimization Controls | Total |
|---|---|---|---|---|---|---|---|
| Participants analysed | 20 | 6 | 6 | 7 | 0 | 39 | |
| Age, Continuous | years | 25 (20 to 46) | 35 (27 to 48) | 26 (22 to 40) | 26 (20 to 46) | — | 26 (20 to 48) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 | 7 | — | 7 |
| Sex: Female, Male: Male | Participants | 20 | 6 | 6 | 0 | — | 32 |
| Race and Ethnicity Not Collected | Participants | — | — | — | — | — | 0 |
| Region of Enrollment: United States | participants | 20 | 6 | 6 | 7 | — | 39 |
6. Primary Endpoint
The registry lists the primary outcome as Microvascular Blood Flow Rate Change, measured over Between baseline and 24 hours.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | Ratio of change |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Microvascular Blood Flow Rate Change.” It is expressed as a ratio of change and summarized using the median and full range. The timeframe is between baseline and 24 hours. The measured quantity is skeletal muscle microvascular blood flow, described as volume multiplied by velocity. The registry says a change ratio greater than 1 indicates that flow rate increased at 24 hours, while a change ratio less than 1 indicates that it decreased. The stated primary outcome target is a 40% increase in participants receiving regadenoson; this is a description of the planned outcome, not a posted numerical finding.
Using a ratio can express follow-up flow relative to baseline rather than in the original measurement units. A median describes the middle of the observed values and is less sensitive than the mean to unusually high or low observations. The full range gives the lowest and highest observed values, but it does not by itself show how values are distributed between those extremes or how precisely the group estimate is known.
CEUS is relevant because the registry’s study rationale focuses on measuring blood flow in small vessels. The endpoint therefore addresses a measurement question alongside the intervention question: whether a change in flow can be assessed with CEUS over the specified timeframe. The registry record does not report the endpoint’s numerical median, range, or a confidence interval, so the observed change and its precision cannot be evaluated from the posted result details.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary endpoint and describes the comparison, but it does not report a numerical result for that endpoint. It is therefore not possible to state whether the median change ratio in the regadenoson group was above, below, or equal to 1, or to characterize its full range. The target of a 40% increase is part of the endpoint description and should not be read as an observed effect.
The primary outcome description identifies measurements in the Regadenoson arm and Sickle Cell Controls arm. It states that 20 participants were in the Regadenoson arm and 6 acted as sickle cell controls. The crisis arm was excluded from this endpoint because its CEUS measurements were not taken in a similar timeframe. These details define the population described for the primary endpoint; they do not supply the group-level outcome values.
The registry lists 3 outcome measures and 0 analyses. The secondary outcomes are named as “MVBF Ratio of Change During a Pain Crisis” and “Microvascular Blood Flow in Sickle Cell Anemia Subjects Versus Control Subjects.” Their presence indicates that the record includes additional measurement questions, but numerical results for them are not reported in the registry record. With no analysis entries, the record also does not provide analysis-level estimates or inferential statistics for these outcomes.
Even if a group difference were reported, the design would require cautious interpretation. This was a non-randomized study, so participants were not assigned to the arms at random according to the registry record. Group characteristics, the reasons for group membership, or other differences could be related to the outcome. The registry’s skip note explicitly says the arms are not a like-for-like control comparison. The comparison can therefore describe the posted groups, but it cannot isolate the effect of regadenoson in the way a randomized comparison is intended to do.
Precision is also not assessable from the available endpoint information. A median and full range are named as the summary format, but their values are not reported. No confidence interval or p-value for the primary endpoint is reported in the registry record. A confidence interval, in general, describes uncertainty around an estimate under the assumptions of the analysis; without an estimate and interval, the degree of uncertainty cannot be quantified.
The safety record provides separate counts of serious and other adverse events across the listed groups. Those counts should not be used to infer efficacy or to substitute for the missing primary endpoint result. The adverse event groups also have different numbers at risk, and the registry does not provide a randomized safety comparison. The posted data support describing the registered design, endpoint definition, and recorded safety counts, but not a conclusion about the size or direction of a blood-flow effect.
9. Statistical Methods Explained
The registry describes the primary endpoint using a ratio of change between baseline and 24 hours. A ratio compares a quantity at one measurement point with a reference quantity. In this study’s endpoint description, a value greater than 1 is interpreted as increased flow at 24 hours, while a value less than 1 is interpreted as decreased flow. The record does not provide the actual ratio values, so those definitions explain how to read a value if reported; they do not indicate which direction the observed data took.
Why summarize with a median and full range?
The registry specifies the median and full range. The median is the central observation after values are ordered, and it can be useful when measurements are skewed or include extreme values. The full range reports the span from the smallest to the largest observation. It communicates the extremes but does not show the distribution’s shape, the frequency of values within the range, or the precision of the median. Neither summary replaces an uncertainty estimate such as a confidence interval.
Microvascular blood flow is described as volume multiplied by velocity. That is the endpoint’s definition in the registry. The record does not report the measurement units for those components, instrument settings, image-processing details, or quality-control procedures. It also does not give the endpoint’s numerical median or full range. Those omissions limit how fully an independent reader can assess the measurement and its variability.
What does the non-randomized design imply?
In a randomized study, allocation is designed to make treatment groups comparable on average with respect to measured and unmeasured characteristics. This record instead lists allocation as non-randomized. General statistical interpretation therefore treats the arm contrast as observational rather than as a randomized treatment effect. Differences in baseline characteristics, clinical status, timing, or other factors could contribute to outcome differences. The record does not provide sufficient detail to determine which such factors were measured or adjusted for, and no adjustment method is reported.
The record also labels the model sequential. That label alone does not establish the order or rules by which participants entered the arms, nor whether the study used sequential statistical monitoring. Details of those procedures and any interim analyses are not reported in the registry record. It would be inappropriate to infer them from the model label.
How should uncertainty and statistical tests be read?
A confidence interval, in general, gives a range of values compatible with an estimate under the analysis assumptions. Its width conveys statistical precision, while its location indicates the range of effect sizes that remain plausible. A p-value, in general, measures how surprising data at least as extreme as those observed would be under a specified null model; it is not a measure of clinical importance. The registry record does not report a confidence interval, p-value, or analysis estimate for the primary endpoint. Statistical significance and precision therefore cannot be assessed from this record.
Repeated measurements at baseline and 24 hours may be related within a participant. In general, analyses of repeated measurements should account for that dependence rather than treat observations from the same person as unrelated. The record describes measurements at both times but does not report the specific statistical method used to analyze them. No model specification, adjustment variables, distributional assumptions, or approach to within-participant dependence is reported.
What do the planning illustrations represent?
The registry’s planning assumptions describe illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These are planning illustrations, not observed power. The time-to-event convention is not relevant to this primary blood-flow endpoint as described. For other outcomes, the planning convention is participants per arm. These assumptions do not establish the trial’s original design rationale or its own sample-size justification; that justification is not reported in the registry record.
Power is a property of a proposed design under specified assumptions, not a retrospective measure of whether a study “had enough power” after its results are known. Planning values depend on the effect and variability assumed. Since the primary numerical effect is not reported in the registry record, the planning illustrations should not be treated as proof that the study detected or failed to detect a clinically meaningful change. The registry does not report the original assumptions used to plan enrollment.
Finally, absence of analysis entries should be distinguished from evidence that no analysis was conducted. The registry lists 0 analyses, but that entry does not explain why analysis information is absent or whether analyses were conducted outside the registry record. The estimand, handling of missing measurements, analysis population, and inferential procedure are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry names 3 outcome measures, including the primary blood-flow endpoint and secondary outcomes concerning blood-flow change during a pain crisis and blood flow in sickle cell anemia subjects versus control subjects. When a study examines multiple outcomes, time points, or group comparisons, the chance of a false-positive finding can increase if each is tested separately without a plan for multiplicity. Statistical methods can address this in different ways, but the appropriate approach depends on the prespecified questions and analysis plan.
A multiplicity strategy is not reported in the registry record. The record does not identify a hierarchy among secondary outcomes, specify whether any analyses were exploratory, or state whether statistical testing was adjusted for multiple comparisons. It also lists 0 analyses, so there are no registry analysis entries to clarify which comparisons were performed or how results were handled.
Missing-data methods and analysis populations are also not described. The registry does not report how unavailable baseline or 24-hour measurements were handled, whether all enrolled participants were included in each analysis, or how exclusions after enrollment were treated. The primary endpoint description gives the numbers in the two endpoint groups and explains why the Sickle Cell Crisis arm was excluded from that comparison, but it does not provide a general missing-data policy or participant-level accounting.
These gaps matter because the choice of outcome, comparison, and analysis population can affect both the estimate and its uncertainty. They do not prove that the study lacked a prespecified plan; they mean that the plan and its implementation are not reported in the registry record. Any interpretation should remain limited to the information that the record documents.
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 |
|---|---|---|---|
| Regadenoson ARM | 5 | 32 | 15.6% |
| Sickle Cell Controls ARM | 0 | 10 | 0.0% |
| Sickle Cell CEU ARM | 3 | 21 | 14.3% |
| Healthy Control ARM | 0 | 21 | 0.0% |
| Technique Optimization Controls | 0 | 7 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Regadenoson ARM | 0 of 32 |
| Sickle Cell Controls ARM | 0 of 10 |
| Sickle Cell CEU ARM | 0 of 21 |
| Healthy Control ARM | 0 of 21 |
| Technique Optimization Controls | 0 of 7 |
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 |
|---|---|
| Regadenoson ARM | 16 of 32 |
| Sickle Cell Controls ARM | 3 of 10 |
| Sickle Cell CEU ARM | 4 of 21 |
| Healthy Control ARM | 1 of 21 |
| Technique Optimization Controls | 0 of 7 |
Most frequent serious adverse event terms
| Event term | Organ system | Regadenoson ARM | Sickle Cell Controls ARM | Sickle Cell CEU ARM | Healthy Control ARM | Technique Optimization Controls |
|---|---|---|---|---|---|---|
| Vaso Occlusive Crisis | Vascular disorders | 4 of 32 | 0 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
| Severe Pain | Vascular disorders | 1 of 32 | 0 of 10 | 3 of 21 | 0 of 21 | 0 of 7 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Regadenoson ARM | Sickle Cell Controls ARM | Sickle Cell CEU ARM | Healthy Control ARM | Technique Optimization Controls |
|---|---|---|---|---|---|---|
| Pain | General disorders | 13 of 32 | 1 of 10 | 3 of 21 | 0 of 21 | 0 of 7 |
| Nausea and/or Vomiting | Gastrointestinal disorders | 3 of 32 | 0 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
| Cough | Respiratory, thoracic and mediastinal disorders | 3 of 32 | 0 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 3 of 32 | 0 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
| Cheilitis | Skin and subcutaneous tissue disorders | 0 of 32 | 0 of 10 | 1 of 21 | 0 of 21 | 0 of 7 |
| Dysguesia | Nervous system disorders | 0 of 32 | 0 of 10 | 0 of 21 | 1 of 21 | 0 of 7 |
| Blurred Vision | Eye disorders | 0 of 32 | 0 of 10 | 1 of 21 | 0 of 21 | 0 of 7 |
| Hypotension | Cardiac disorders | 0 of 32 | 1 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
| Hot flash | Blood and lymphatic system disorders | 0 of 32 | 1 of 10 | 0 of 21 | 0 of 21 | 0 of 7 |
Serious events with the highest arm-level rate: severe pain (14.3%), vaso occlusive crisis (12.5%).
The adverse-event record lists serious adverse events, other adverse events, and deaths separately for each group. In the Regadenoson ARM, 5 of 32 participants at risk are listed with serious adverse events, and 16 of 32 with other adverse events. In the Sickle Cell Controls ARM, the corresponding counts are 0 of 10 and 3 of 10. In the Sickle Cell CEU ARM, they are 3 of 21 and 4 of 21. In the Healthy Control ARM, they are 0 of 21 and 1 of 21. In Technique Optimization Controls, they are 0 of 7 and 0 of 7. The record lists 0 deaths in each group.
The registry identifies “Severe Pain” at 14.3% and “Vaso Occlusive Crisis” at 12.5% among the leading serious adverse-event terms. It does not attribute those percentages to a specific arm in the information available for this summary, so they should not be assigned to a group. The record does not provide event timing, duration, relatedness assessment, or a randomized safety comparison.
Counts across groups should be read in light of their different numbers at risk and the non-randomized design. They describe the adverse events recorded for these groups; they do not establish that an intervention caused an event or that groups are directly comparable. These safety counts also do not answer the primary blood-flow question.
12. What the Result Does, and Does Not, Mean
The study addresses a measurement problem described in its background: whether CEUS can be used to assess changes in blood flow in people with sickle cell disease. Its primary endpoint focuses on skeletal muscle microvascular blood flow at baseline and 24 hours, with a ratio intended to express whether measured flow increased or decreased. The endpoint definition and the group composition are reported, but the numerical primary outcome is not reported in the registry record.
As a result, the record does not establish the observed direction or magnitude of the blood-flow change, how variable the measurements were, or how precisely any group estimate was known. The stated 40% increase is the endpoint’s target description, not evidence that the increase occurred. Without numerical estimates and uncertainty measures, statistical evidence for or against a change cannot be assessed.
The study’s non-randomized allocation further limits causal interpretation. The primary endpoint comparison concerns participants in the regadenoson and sickle cell control arms, but the registry warns that the arms are not a like-for-like control comparison. Differences between groups could reflect factors other than the intervention. The findings, if numerical results were available, would need interpretation in the context of that design rather than as a randomized treatment effect.
The record does describe a broad set of participants and procedures, including CEUS arms involving people with sickle cell anemia and healthy controls. Those groups have different stated purposes and should not be combined into a single comparison without an analysis rationale. The crisis arm is specifically excluded from the primary endpoint because its CEUS measurement timing was not similar to that of the primary comparison arms.
Accordingly, the defensible conclusion from the registry record is about what was studied and how the primary outcome was defined, not whether regadenoson changed blood flow or whether CEUS proved feasible. The study’s central hypothesis is stated, but a numerical result addressing it is not reported in the registry record.
13. Why This Trial Matters Statistically
This study brings together an intervention question and a measurement question. The intervention is regadenoson, while CEUS is the technique used to assess microvascular blood flow. Distinguishing those roles is important: a study can investigate whether a measurement approach captures change without establishing that the intervention causes a beneficial clinical effect. The registry frames CEUS feasibility as a hypothesis and defines a blood-flow endpoint for assessment.
For biostatistical interpretation, the record illustrates why design labels and endpoint definitions do not replace results. The non-randomized allocation, absence of masking, sequential model label, and distinct arm descriptions all affect the questions that can be answered. In particular, comparisons among groups may be influenced by how participants came to be in each group. The record itself cautions that the arms are not a like-for-like control comparison.
The endpoint also illustrates the value and limits of a clear summary measure. A ratio and its direction-of-change interpretation make the target quantity understandable, while the median and full range describe a planned way to summarize it. Yet without the actual summaries and uncertainty estimates, readers cannot assess the observed effect or its precision. A well-defined endpoint is necessary for interpretation, but it is not a substitute for a posted result.
Finally, the difference between an outcome list and an analysis record matters. Several outcomes are named, but 0 analyses are listed. The registry therefore does not document how the endpoint data were analyzed, how multiplicity was handled, or how missing measurements were treated. These details are central to judging the robustness and reproducibility of a clinical analysis. The record is informative about study structure and the intended measurement question, while leaving key statistical results and methods unreported.
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 primary limitation for statistical interpretation is that the registry record does not report numerical results for the primary endpoint. Although it specifies the summary type, timeframe, direction-of-change rule, and endpoint population, it gives no median change ratio or full range. The result’s precision is also not reported; there is no confidence interval or p-value for the endpoint in the record.
The non-randomized design and the registry’s warning that the arms are not a like-for-like control comparison restrict interpretation of group contrasts. The arm descriptions include participants with sickle cell anemia and healthy controls with different stated roles. Details about participant selection, baseline comparability, and any adjustment for differences between groups are not reported in the registry record. No masking was used.
Measurement and analysis details are limited. The registry defines microvascular blood flow as volume multiplied by velocity and identifies CEUS as the measurement procedure, but does not report technical measurement procedures, reliability information, or quality-control methods. It lists 0 analyses. The statistical model, handling of repeated measurements, missing-data approach, analysis populations, multiplicity strategy, and interim analysis plan are not reported in the registry record.
The primary endpoint population is described as 20 participants in the Regadenoson arm and 6 sickle cell controls, while total enrollment is 91. The record explains that the Sickle Cell Crisis arm is excluded from the primary endpoint because its measurement timing differed, but it does not give a full account of how all enrolled participants contribute to each outcome. These limitations mean that the registry record supports a description of the design and endpoint, but not an independent assessment of the estimated blood-flow effect.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Microvascular Blood Flow in Sickle Cell Anemia — NCT01566890.
- Registry record last updated 2024-06-26; status last verified 2024-06.
- Results first posted 2024-06-26.
- 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
NCT01566890, “Microvascular Blood Flow in Sickle Cell Anemia,” is recorded as completed, with enrollment of 91. It is a non-randomized, unmasked, sequential study sponsored by Versiti Blood Health. The study start is recorded as 2012-07, and primary completion as 2019-07-05.
The primary endpoint is the ratio of skeletal muscle microvascular blood flow change between baseline and 24 hours, summarized by the median and full range. The primary comparison description identifies 20 participants in the Regadenoson arm and 6 sickle cell controls. The numerical endpoint result is not reported in the registry record, and 0 analyses are listed.
The record lists 3 outcome measures and five study arms, including regadenoson, sickle cell CEUS, sickle cell control, healthy control, and technique optimization groups. Safety counts are recorded by group, with 0 deaths listed in each. Because allocation was non-randomized and the record cautions that the arms are not a like-for-like control comparison, group differences cannot be interpreted as a randomized treatment effect.