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 A Pilot Study of Hemin Therapy for Gastroparesis (Diabetes Mellitus) (NCT01206582), a randomized phase 2 study. The primary outcome is Venous Plasma Heme-oxygenase 1 (HO1) Protein Concentration.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01206582 |
| Phase | Phase 2 |
| Condition | Gastroparesis, Diabetes Mellitus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
People with diabetes mellitus and gastroparesis, described in the registry as having slow gastric emptying. The registry record does not report further eligibility details, such as age range, disease duration, or the criteria used to confirm gastroparesis.
Intervention
Hemin was administered by intravenous infusion. The registry describes hemin diluted in 25% albumin to a concentration of 2.4 mg/mL, at a dose of 1.25 mL/Kg and an infusion rate of 60 mL/hour. The schedule was 10 infusions over 8 weeks.
Comparator
The comparator was albumin, administered in 10 intravenous infusions over 8 weeks. The registry record identifies this arm as Albumin but does not give further details about its preparation or infusion rate.
Primary question
The primary outcome was venous plasma heme-oxygenase 1 (HO1) protein concentration, measured at baseline, day 3, day 7, and day 56. The study was designed to examine whether hemin could increase HO1 production and improve gastric emptying and symptoms. The registry record does not report numerical primary-outcome results, so the measured difference between the groups and its precision cannot be described.
These elements define the clinical comparison, but they do not establish what the trial found. In particular, the primary outcome is a plasma protein concentration rather than a direct measure of gastric emptying or symptoms. Gastrointestinal symptoms and autonomic functions were among the secondary outcomes, but numerical results for those measures are not reported in the registry record. The record also does not report the eligibility criteria or explain how participants were assigned to the two arms. The clinical question is therefore identifiable, while important details about the enrolled population and the results remain unavailable.
3. Trial Design
This was a randomized, quadruple-masked, parallel-group phase 2 study sponsored by Mayo Clinic. The registry record lists enrollment as 20 and the status as completed. The recorded study start is 2010-05, and primary completion is recorded as 2014-12. These dates describe the registry entry; they do not establish the duration of follow-up for each participant.
The intervention arm received hemin, and the comparator arm received albumin. The hemin description specifies dilution in 25% albumin, a concentration of 2.4 mg/mL, a dose of 1.25 mL/Kg, and an infusion rate of 60 mL/hour. Both arms are described as receiving 10 intravenous infusions over 8 weeks. The record does not explain how the masking was maintained, who was masked, or whether the infusion procedures were otherwise matched.
Randomized allocation is intended to make treatment groups comparable on average, including for characteristics that are not measured. It does not guarantee that groups will be identical, particularly in a small pilot study. The registry record does not report the randomization sequence, allocation concealment procedures, or the specific implementation of the parallel design.
The registered primary outcome was venous plasma HO1 protein concentration. It was assessed at baseline, day 3, day 7, and day 56 using a human HO1 enzyme-linked immunosorbent assay. The record lists gastrointestinal symptoms, autonomic functions, and several blood and laboratory measures as secondary outcomes. It also identifies 11 outcome measures and 6 analyses, without describing the full analysis plan. The available record does not provide numerical outcome estimates or detail whether all registered outcomes were analyzed as planned.
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 | Hemin | Albumin |
|---|---|---|
| STARTED | 11 | 9 |
| COMPLETED | 9 | 7 |
| NOT COMPLETED | 2 | 2 |
Reasons for not completing this period:
| Reason | Hemin | Albumin |
|---|---|---|
| Withdrew prior to study | 1 | 0 |
| Discontinued intervention before week 8 | 1 | 2 |
Analysis population for the primary outcome, as defined in the registry: Total number of subjects analyzed varied per time period due to discontinuations, subject and data availability. Subjects analyzed are presented per category as (n=hemin, albumin arms).
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 | Hemin | Albumin | Total |
|---|---|---|---|---|
| Participants analysed | 11 | 9 | 20 | |
| Age, Continuous | years | 45.9 (SD 14.4) | 35.2 (SD 14.9) | 41.1 (SD 15.3) |
| Sex: Female, Male: Female | Participants | 9 | 9 | 18 |
| Sex: Female, Male: Male | Participants | 2 | 0 | 2 |
| Region of Enrollment: United States | participants | 11 | 9 | 20 |
6. Primary Endpoint
The registry lists the primary outcome as Venous Plasma Heme-oxygenase 1 (HO1) Protein Concentration, measured over baseline, day 3, day 7, day 56.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | ng/mL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was venous plasma heme-oxygenase 1 (HO1) protein concentration, measured in ng/mL. HO1 is the protein the study was designed to assess as a potential biological response to hemin. The registry says that levels were assessed with a human HO1 enzyme-linked immunosorbent assay (ELISA) kit. It does not report further assay-performance information, such as precision or limits of measurement.
Concentration is a continuous measure, and the registry identifies the summary parameter as a mean with standard error. A mean describes the central level of the measurements; the standard error describes the precision of an estimated mean, rather than the spread of individual participant measurements. Comparisons of means can help describe whether the measured protein concentration differed between treatment groups or over time, provided the analysis accounts appropriately for the study design and available data.
The outcome was assessed at baseline, day 3, day 7, and day 56. Repeated measurements can show how a biomarker changes over the assessment period, but observations from the same participant are related. The registry record does not report the statistical model used to handle those repeated measurements, nor does it provide the numerical HO1 results. The endpoint is therefore clear as a biological measurement, while the magnitude, direction, and precision of any observed change are not reported in the registry record.
HO1 concentration is not itself a direct measurement of gastric emptying or symptom burden. Those clinical domains were part of the study rationale or listed among secondary outcomes, but the primary endpoint represents the plasma protein measurement.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies a randomized comparison of hemin and albumin, but it does not report numerical results for the primary HO1 outcome. Consequently, there is no registry-reported estimate of the group difference, change over time, confidence interval, or hypothesis-test result to interpret. The direction and size of any observed effect, and how precisely it was estimated, are not reported in the registry record. The stated purpose of the study is not evidence that the intended biological or clinical changes occurred.
The primary outcome was measured at baseline, day 3, day 7, and day 56. A complete interpretation would need to distinguish the starting values from measurements after treatment began and to clarify whether the comparison concerns changes within each group, differences between groups at a time point, or a treatment-by-time pattern. Those analytic details and estimates are not reported in the registry record. It is not possible to infer a treatment effect from the outcome definition or the trial design alone.
The registry says the number of subjects analyzed varied by time period because of discontinuations, subject availability, and data availability. It also says that the analyzed subjects are presented by category as counts for the hemin and albumin arms. This means the number contributing to an estimate may differ across time points. The specific analyzed counts and the reasons for missing observations at each assessment are not reported in the record presented in the registry record. Without them, the extent and possible influence of missing outcome data cannot be evaluated.
Safety counts are reported separately from the primary endpoint. The registry lists no serious adverse events among participants at risk in either arm, and lists other adverse events in both arms. These counts describe recorded events in a small completed pilot study; they are not a substitute for the unreported primary-outcome estimates, and they do not determine the balance of benefit and risk.
Any planning illustration based on an observed effect should be read as a hypothetical design calculation, not as a measure of the trial's observed power. Such an illustration depends on assumptions about the effect to detect and the statistical procedure. The registry record does not report a sample-size justification or enough numerical outcome information to independently assess a planning calculation. More broadly, the absence of outcome estimates means no conclusion about the primary comparison can be drawn from this record alone.
9. Statistical Methods Explained
The primary outcome is continuous: each measurement is a concentration expressed in ng/mL. For a continuous outcome, a mean is a familiar way to describe the central level. The registry specifies a mean and standard error, but does not report the values themselves. The mean and standard error answer different questions. The mean locates the estimated average, while the standard error indicates how uncertain that estimated average is under the statistical model. It is not the standard deviation, which describes variability among individual measurements.
A confidence interval is a range of values compatible with the data and the assumptions of the analysis. It communicates the precision of an estimate: a narrower interval indicates greater precision, while a wider interval indicates less precision. The registry record does not report a confidence interval for the primary outcome or any other numerical uncertainty estimate. Without an effect estimate and its uncertainty, a reader cannot judge whether the observed difference, if any, was small or large relative to the precision of the study.
How can repeated measurements be analyzed?
HO1 concentration was assessed at baseline, day 3, day 7, and day 56. Measurements from one participant over time are generally correlated: a person's later value may be related to that person's earlier value. A suitable analysis of repeated measurements should account for this dependence rather than treating every measurement as unrelated. It may also distinguish a change over time from a difference between treatment groups, and assess whether the pattern over time differs by group. These are general statistical considerations, not a description of the analysis used in this trial. The registry record does not report the model, covariance assumptions, or contrast used for the primary analysis.
Baseline measurements can help describe the groups before treatment and can be used in some analyses to improve precision. Whether the primary comparison adjusted for baseline, and how baseline values were handled, are not reported in the registry record. Nor does the record specify whether the primary estimate was based on a comparison at a particular follow-up time, an average across follow-up times, or a model using all scheduled measurements.
What does randomization contribute?
Random allocation aims to reduce systematic differences between groups at the start of a trial. In general, it supports a causal comparison when allocation is implemented as intended and participants are analyzed in a way that respects their assigned groups. Randomization does not remove uncertainty from a small study, prevent missing data, or guarantee balance on every characteristic. The registry lists the allocation as randomized, but does not report the sequence-generation method, concealment procedures, or the analysis population used. It is therefore not possible to assess those implementation details from the registry record.
Masking is described as quadruple. In general, masking can reduce the influence of expectations on participants, clinicians, outcome assessors, or other trial personnel, depending on who is masked. The registry does not identify the masked roles or describe how the hemin and albumin infusions were made indistinguishable. The label alone does not establish which potential sources of bias were controlled.
How should planning calculations be understood?
Planning calculations can illustrate the number of participants per arm that would be needed to detect an assumed effect under stated statistical conditions. They are not evidence that an effect was observed, and they are not observed power. The registry's stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. For outcomes other than time-to-event outcomes, the convention is participants per arm.
These assumptions define a planning exercise; they do not establish the original design rationale. The registry record does not report the trial's sample-size justification or explain whether its planning assumptions were used when the study was designed. A calculation that uses an observed effect is also dependent on the estimate chosen as its starting point. If that estimate is imprecise, the resulting planning illustration can be unstable. It should not be treated as proof that the trial had adequate power, or that a non-significant result would establish no effect. Numerical planning values are not reported in the registry record.
What can be inferred from an unadjusted estimate?
A simple unadjusted comparison describes the observed groups without controlling for other variables. It can be informative as a descriptive summary, but its interpretation depends on the design, the outcome distribution, missing observations, and how repeated measurements are handled. Recalculation from summary statistics may not match a sponsor's analysis if that analysis used a different model or additional information. The registry record does not provide a sponsor analysis or numerical summary statistics for recalculation. No independent effect estimate or significance test can therefore be reconstructed from the information reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies 11 outcome measures and 6 analyses. It lists HO1 concentration as the primary outcome and includes gastrointestinal symptoms, autonomic functions, serum creatinine, coagulation measures, hemoglobin, erythrocyte count, and leukocyte and platelet counts among secondary outcomes. When several outcomes, time points, or analyses are examined, the chance of obtaining at least one apparently notable result can increase. General approaches to multiplicity include prespecifying a primary comparison, adjusting significance thresholds, or treating secondary analyses as exploratory. The registry record does not report a multiplicity adjustment or describe how the several outcomes and analyses were prioritized.
The primary measure was assessed at baseline, day 3, day 7, and day 56. Multiple time points can create more than one possible comparison, but the record does not identify which time contrast was designated as primary or how the repeated assessments were handled. It is not possible to determine from the record whether all analyses were prespecified, whether any were exploratory, or whether the reported analysis set differs from the planned set.
The registry states that the number of subjects analyzed varied by time period because of discontinuations, subject availability, and data availability. This is relevant because estimates based on different available participants at different visits may be affected if the reasons for missing measurements are related to outcomes or treatment. The specific number analyzed at each time point and the reasons for each missing observation are not reported in the registry record.
Statistical methods for missing data can include analyses of available observations, imputation, or models that use incomplete repeated measurements under explicit assumptions. These approaches rely on different assumptions and can yield different estimates. The registry record does not report an imputation method, a missing-data sensitivity analysis, or whether participants were analyzed according to randomized assignment. It also does not define an intention-to-treat, per-protocol, or other analysis population. Therefore, the impact of discontinuations and unavailable data on the primary analysis cannot be assessed.
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 |
|---|---|---|---|
| Hemin | 0 | 11 | 0.0% |
| Albumin | 0 | 9 | 0.0% |
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 |
|---|---|
| Hemin | 5 of 11 |
| Albumin | 7 of 9 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hemin | Albumin |
|---|---|---|---|
| Headache | General disorders | 2 of 11 | 3 of 9 |
| Nausea | Gastrointestinal disorders | 1 of 11 | 3 of 9 |
| Dizziness or light headedness | General disorders | 2 of 11 | 0 of 9 |
| Maculopapular rash | Skin and subcutaneous tissue disorders | 0 of 11 | 1 of 9 |
The registry reports serious adverse event counts of 0 among 11 participants at risk in the hemin arm and 0 among 9 participants at risk in the albumin arm. It reports other adverse events affecting 5 among 11 at risk in the hemin arm and 7 among 9 at risk in the albumin arm. These are counts reported for the two groups, not estimates of comparative risk adjusted for follow-up or other factors. The registry record does not provide event descriptions for these other adverse events in the registry record.
A count of zero serious adverse events in a group means that none were recorded for that group in the registry results; it does not demonstrate that serious events are impossible or rule out uncommon harms. This was a completed pilot study, and the event counts alone do not establish that the groups had equivalent safety profiles. The registry does not report confidence intervals or a formal comparison of adverse-event rates.
Deaths are not reported in the registry record. That should not be interpreted as a zero count. The record also does not provide information in these results about event timing, severity beyond the serious-event classification, duration, or attribution to treatment. Safety counts should therefore be read as descriptive registry information, with limited detail for assessing differences between the arms.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized phase 2 comparison of hemin with albumin in a study of diabetic gastroparesis. Its primary endpoint was plasma HO1 protein concentration, measured at baseline, day 3, day 7, and day 56. This establishes what the study set out to measure, but not what the comparison found. Numerical primary-outcome estimates, measures of uncertainty, and test results are not reported in the registry record.
The study rationale also refers to gastric emptying and symptoms, and gastrointestinal symptoms are listed among the secondary outcomes. However, the primary endpoint is a biological measure of plasma HO1 concentration. A change in a biomarker would not by itself establish a change in gastric emptying, symptoms, or any other clinical outcome. Numerical results for those clinical outcomes are not reported in the registry record.
The study is labeled phase 2 and pilot, and the registry lists enrollment as 20. Such a study can provide information about feasibility or preliminary outcomes, depending on its design and reporting, but those purposes and any design rationale are not specified in detail. A small pilot study also generally leaves substantial uncertainty around estimates, especially when observations are missing or divided across several outcomes and time points. The record states that the analyzed population varied by time period, but does not report the specific counts at each assessment or the missing-data methods.
The adverse-event counts offer a limited descriptive view and should not be read as a definitive comparison of safety. The absence of recorded serious events does not prove absence of risk, and the registry does not report deaths. Overall, the available record supports a description of the trial question, design, endpoints, and reported event counts. It does not support a conclusion about the magnitude or direction of the primary outcome, clinical benefit, or a definitive safety difference between groups.
13. Why This Trial Matters Statistically
This trial raises several statistical issues that are common in small clinical studies. First, its primary endpoint is a continuous biomarker measured repeatedly over time. That design calls for clarity about the main treatment contrast, the role of baseline values, and how within-participant correlation is handled. The registry specifies the assessment times and summary parameter, but does not report the analysis model or the primary contrast.
Second, the number of observations available varies across time periods because of discontinuations, subject availability, and data availability. A changing analysis population can affect both the precision and interpretation of estimated means. Understanding the influence of missingness requires the analyzed counts, reasons for missing observations, and the assumptions or sensitivity analyses used. Those details are not reported in the registry record.
Third, the registry lists 11 outcome measures and 6 analyses. When a study includes several outcomes and measurement times, the prespecified primary comparison and the handling of multiple analyses matter for interpreting any statistically notable finding. The record identifies a primary endpoint but does not report a multiplicity strategy or provide numerical outcome results.
Finally, safety counts and planning illustrations answer different questions from an efficacy analysis. Event counts describe what was recorded, while planning calculations describe hypothetical requirements under assumptions; neither can substitute for the missing primary estimate and its uncertainty. The stated planning assumptions do not reveal the trial's original sample-size justification. These features make transparent reporting of estimates, confidence intervals, analysis populations, and missing-data handling especially important for readers assessing a pilot trial.
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 main limitation for interpreting this trial record is the absence of numerical primary-outcome results. Although the endpoint, measurement times, and assay approach are described, the actual HO1 concentrations, between-group estimates, changes from baseline, and uncertainty measures are not reported in the registry record. The direction and magnitude of the primary finding therefore cannot be evaluated.
The record says the number analyzed varied by time period because of discontinuations, subject availability, and data availability. It does not report the analyzed count at each time point, reasons for individual missing measurements, or a missing-data method. These omissions prevent assessment of whether estimates could be affected by who remained available for measurement.
Several analysis details are also unavailable. The registry does not report the statistical model, the primary time-point contrast, whether baseline adjustment was used, or the analysis population. It lists 11 outcome measures and 6 analyses but does not explain their prespecification or any approach to multiplicity. These points limit interpretation of the intended inferential framework.
The clinical population is only broadly described as people with diabetes mellitus and gastroparesis. More detailed eligibility criteria and baseline participant characteristics are not reported in the registry record. The masking designation is quadruple, but the masked roles and procedures are not described. The adverse-event summary is similarly limited: deaths are not reported, and further details about the other adverse events are unavailable in the registry record. These limitations mean the record supports a description of the study design, but not a full assessment of its outcomes or conduct.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Pilot Study of Hemin Therapy for Gastroparesis (Diabetes Mellitus) — NCT01206582.
- Registry record last updated 2016-02-04; status last verified 2016-01.
- Results first posted 2016-02-04.
- 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 describes a completed randomized, quadruple-masked, parallel-group phase 2 pilot study sponsored by Mayo Clinic. Enrollment is listed as 20. The study compared hemin with albumin in people with diabetic gastroparesis; both arms are described as receiving 10 intravenous infusions over 8 weeks.
The primary outcome was venous plasma HO1 protein concentration in ng/mL, assessed at baseline, day 3, day 7, and day 56. The registry lists 11 outcome measures and 6 analyses. It reports that the number analyzed varied across time periods because of discontinuations, subject availability, and data availability.
Serious adverse events are recorded as 0 in each arm; other adverse events are also listed for both arms. Deaths are not reported in the registry record. Numerical results for the primary endpoint, analysis details, and missing-data methods are not reported in the registry record, limiting assessment of the treatment comparison.