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 HeRO Graft Compared to Permanent Catheters for End Stage Renal Disease (ESRD) Patients Receiving Hemodialysis (NCT01343251), a registered phase not stated study. The primary outcome is Mortality.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01343251 |
| Phase | Phase not stated |
| Condition | End Stage Renal Disease (ESRD) |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 33 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merit Medical Systems, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The registry concerns patients with end stage renal disease receiving hemodialysis. It records an enrollment of 33. The eligibility criteria, participant characteristics at baseline, and details of how patients entered the study are not reported in the registry record.
Intervention
The HeRO Graft group comprised patients who were evaluated and received a HeRO Graft implant for hemodialysis. The registry describes the study as a prospective analysis of this vascular access approach. Further details about implantation, care, or follow-up procedures are not reported in the registry record.
Comparator
The control group comprised patients who were evaluated but did not receive a HeRO Graft for any reason. The official title describes cuffed catheter access as the comparator. The record does not state that assignment was randomized, and the reasons for not receiving a HeRO Graft are not reported in the registry record.
Primary question
The primary question is whether mortality differed between the study arms over the one-year timeframe. The study description also names quality of life, bacteremia, vascular interventions, hospitalizations, and death as outcomes of interest. Numerical mortality estimates and an inferential comparison are not reported in the registry record.
This is a comparison of observed groups, not a randomized treatment comparison: the registry does not state an allocation method, and the control group is defined by not receiving the graft for any reason. That design matters when interpreting differences. Patient circumstances that affect access choice may also be associated with outcomes, so a difference between the groups would not, by itself, establish that access type caused the difference. The registry record does not report details that would allow those factors to be assessed.
3. Trial Design
The study is listed as completed and is described in its official title as a prospective analysis of Hemodialysis Reliable Outflow (HeRO) vascular access graft versus cuffed catheter access. The registry gives a start date of 2011-01 and a primary completion date of 2013-12. Enrollment is recorded as 33. These registry entries describe the study as registered; they do not establish how many participants contributed data to each outcome analysis.
The HeRO Graft arm includes patients evaluated and receiving a HeRO Graft implant. The control arm includes non-HeRO patients who were evaluated but did not receive the graft for any reason. The registry explicitly notes that this is not a randomized comparison and that the arms are not a like-for-like control comparison. Allocation is not stated. The record does not explain why individual patients received or did not receive the graft, or whether the groups differed in clinical characteristics before follow-up.
The stated objective was to compare outcomes over one year, including quality of life and the incidence of bacteremia, vascular interventions, hospitalizations, and death. Mortality is identified as the primary outcome, with infection, quality of life, intervention, and hospitalization outcomes also listed. The registry records five outcome measures and eight analyses, but the analysis methods, outcome-specific assessment schedules, and analysis populations are not reported in the registry record.
The completed status and study dates do not supply the missing outcome estimates. In particular, the registry record does not report numerical mortality results, group-level comparative estimates, confidence intervals, or p-values in the registry record for this analysis. It also does not report the recruitment process, follow-up completeness, or the number of participants contributing to each analysis. Those omissions limit the conclusions that can be drawn from the design description alone.
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 | HeRO Graft | Control |
|---|---|---|
| STARTED | 16 | 17 |
| COMPLETED | 16 | 17 |
| NOT COMPLETED | 0 | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | HeRO Graft | Control | Total |
|---|---|---|---|---|
| Participants analysed | 16 | 17 | 33 | |
| Age, Continuous | years | 56.69 (SD 11.08) | 63.12 (SD 11.49) | 60.00 (SD 11.38) |
| Sex: Female, Male: Female | Participants | 9 | 12 | 21 |
| Sex: Female, Male: Male | Participants | 7 | 5 | 12 |
| Region of Enrollment: United States | participants | 16 | 17 | 33 |
6. Primary Endpoint
The registry lists the primary outcome as Mortality, measured over 1 year.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants who died |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is mortality, defined in the registry as the percentage of participants who died, with a timeframe of one year. It is intended to compare mortality between the HeRO Graft and control arms. Mortality is a binary outcome at the participant level: a participant either has the recorded event within the defined period or does not. A percentage is a way to describe the frequency of that event in a group.
As a general statistical matter, mortality is relevant to an evaluation of a clinical intervention because it is an important outcome in its own right and can be counted without relying on a subjective rating scale. The interpretation depends on clear definitions of the eligible analysis population, follow-up period, and handling of participants whose status is unknown. Those details are not reported in the registry record. The primary outcome entry lists the parameter as a number, while its unit describes a percentage; the record does not clarify that presentation.
The registry entries available for this analysis do not include the numerical mortality percentage for either arm, a between-arm estimate, or its uncertainty. The adverse-event information includes a null entry for deaths in both groups, but that entry is not a reported mortality comparison and cannot fill in the primary endpoint result. Therefore, the endpoint’s purpose and timeframe can be described, but the observed mortality result and its precision cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies mortality over one year as the primary outcome and describes a prospective comparison of patients who received a HeRO Graft with patients who did not. It also flags that the arms are not a like-for-like control comparison and that allocation is not stated. Those design features should guide any interpretation of a group contrast: even if outcome estimates were available, differences could reflect factors associated with access selection as well as differences associated with the access itself.
The numerical primary outcome results are not reported in the registry record. No mortality percentage by arm, comparative effect estimate, confidence interval, or p-value appears in the registry record for this analysis. The registry’s adverse-event group entries list deaths as null, which is missing information in that entry rather than a numerical mortality estimate. It should not be interpreted as evidence that no deaths occurred or as a substitute for the primary outcome analysis.
The record lists infection, quality of life, intervention, and hospitalization outcomes in addition to mortality. It does not give numerical comparative results for these outcomes in the registry record. The serious-event terms include percentages, but those entries are not identified as effect estimates comparing the two arms. They therefore cannot establish a comparative benefit or harm, and they should not be read as rates for the primary endpoint.
Precision is also impossible to judge without estimates and uncertainty intervals. In general, a confidence interval describes the range of values compatible with the data and the statistical method; a wider interval indicates less precision. No such intervals are reported in the registry record. Likewise, a p-value, if reported, would address compatibility with a specified null model and would not resolve the nonrandomized nature of the comparison or explain the size and practical importance of an observed difference.
The enrollment entry is 33, but enrollment alone does not tell how many participants had complete one-year follow-up or contributed to a particular outcome. The registry record does not report missing outcome counts, group-specific analysis sizes, or the treatment of incomplete follow-up. The central interpretation is therefore limited: the record describes the question and the study groups, but the registry entries available do not support a quantitative conclusion about the mortality contrast or the other outcome comparisons.
9. Statistical Methods Explained
The registry identifies mortality as the primary outcome, describes it as a percentage of participants who died, and gives a one-year timeframe. In general, this kind of endpoint begins with a participant-level event indicator: the event is recorded as present or absent for the defined follow-up period. Group summaries can then describe the observed event frequency. A comparison may express the difference or relative contrast between groups, but the registry record does not report which comparative measure was used or provide its estimate.
For a binary outcome, a confidence interval communicates uncertainty around an estimated event frequency or group contrast. It reflects both the observed data and the assumptions of the statistical method. A narrow interval indicates greater precision than a wide interval, but an interval does not correct for bias from group selection or other design limitations. No confidence intervals are reported in the registry record, so neither precision nor the range of plausible comparative effects can be evaluated.
A hypothesis test and its p-value, if used, would address how compatible the observed data are with a specified null hypothesis under the model. A p-value does not give the probability that the null hypothesis is true, and it does not measure the clinical importance of a difference. The registry entries do not report a p-value or a hypothesis-testing procedure. They also do not state whether analyses were adjusted for baseline characteristics, how covariates were selected, or what statistical model was used.
The primary endpoint is a count-based outcome summarized as a percentage. General methods for binary outcomes include direct comparisons of proportions and regression models for binary responses. These approaches can differ in their assumptions and in the interpretation of their estimates. This description is general; it does not identify the method used in this study. The registry record does not report enough detail to determine the model, any adjustment, or the exact denominator for the outcome summaries.
The design is not described as randomized. The record states that allocation is not stated and that the arms are not a like-for-like control comparison. In a nonrandomized comparison, differences in participant characteristics or clinical circumstances can be associated with both group membership and outcomes. Statistical adjustment can sometimes address measured differences, but it cannot automatically eliminate unmeasured confounding. The registry entries do not report baseline comparisons or an adjustment strategy, so it is not possible to assess whether or how such differences were considered.
The registry lists eight analyses and five outcome measures. That indicates that more than one analysis or outcome was registered, but it does not explain the analysis hierarchy or how results were selected for emphasis. When many hypotheses are tested, the chance of at least one apparently notable result can increase. Methods for addressing multiplicity may include prespecifying a primary analysis or adjusting inference across tests. Whether any such approach was used is not reported in the registry record. The listed count alone does not establish that a particular correction was necessary or applied.
The record also includes planning assumptions for a sample-size illustration: a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect expressed as a stated fraction of the observed effect. The illustration is based on the observed effect and is not the trial’s own design justification. No sample-size values or observed effect estimates are reported in the registry record for this analysis. Such calculations are planning illustrations, not observed power; they cannot establish the probability that this completed study detected an effect.
For time-to-event outcomes, a general method may use event counts and assumptions about the event process; for other outcomes, a sample-size illustration may express the number of participants per arm. The registry description distinguishes those conventions, but mortality is presented as a percentage and the registry entries do not identify a time-to-event analysis. The model and its assumptions for the primary endpoint are not reported in the registry record. No analysis can be reconstructed from the group descriptions alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists five outcome measures and eight analyses. The registry entries available for this analysis identify mortality as the primary outcome and describe infection, quality of life, intervention, and hospitalization outcomes, but they do not give a complete analysis hierarchy or specify which analysis was primary for each secondary outcome. The registry record does not report whether multiplicity was addressed through prespecification, adjustment, or another approach. With multiple outcomes or analyses, selective emphasis can make isolated findings difficult to interpret; the number of listed analyses by itself does not reveal how the investigators handled that issue.
Missing-data methods are also not reported in the registry record. The registry entries do not state how many participants had outcome data at each assessment, whether follow-up was complete, how unknown vital status was handled, or whether any imputation or sensitivity analysis was used. The null death entries in the adverse-event group information are not an explanation of missingness and should not be treated as zero events.
The primary outcome entry does not identify an analysis population, and the population field is blank. The record does not state whether analyses followed an intention-to-treat principle, included only participants who received the assigned access, or used another population definition. Since the groups are not randomized and the control group is defined by not receiving a graft for any reason, the precise definition of group membership and analysis eligibility is particularly important. Those details are not reported in the registry record.
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 |
|---|---|---|---|
| HeRO Graft | 16 | 16 | 100.0% |
| Control | 15 | 17 | 88.2% |
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 |
|---|---|
| HeRO Graft | 0 of 16 |
| Control | 0 of 17 |
Most frequent serious adverse event terms
| Event term | Organ system | HeRO Graft | Control |
|---|---|---|---|
| Infection | Infections and infestations | 6 of 16 | 12 of 17 |
| Intervention to Restore Patency | Vascular disorders | 12 of 16 | 4 of 17 |
| Death-Unknown Cause | General disorders | 3 of 16 | 3 of 17 |
| Access Exchange | Vascular disorders | 1 of 16 | 4 of 17 |
| Access Creation | Vascular disorders | 0 of 16 | 3 of 17 |
| Bleeding | Blood and lymphatic system disorders | 2 of 16 | 0 of 17 |
| Chest Pain | Cardiac disorders | 1 of 16 | 1 of 17 |
| Congestive Heart Failure | Cardiac disorders | 0 of 16 | 2 of 17 |
| Injury-Fall | Injury, poisoning and procedural complications | 1 of 16 | 1 of 17 |
| Access Explant | Vascular disorders | 2 of 16 | 0 of 17 |
Serious events with the highest arm-level rate: intervention to restore patency (75.0%), infection (70.6%), access exchange (23.5%), death-unknown cause (18.8%), access creation (17.6%).
The serious adverse-event information lists HeRO Graft and Control groups with counts at risk and counts affected. For serious events, the HeRO Graft group has 16 at risk and 16 affected; the Control group has 17 at risk and 15 affected. The registry also lists other-event counts: 16 at risk and 0 affected for HeRO Graft, and 17 at risk and 0 affected for Control. These are the registry entries; they are not a substitute for the primary mortality comparison.
The serious-event terms are listed with percentages, including Intervention to Restore Patency at 75.0%, Infection at 70.6%, Access Exchange at 23.5%, Death-Unknown Cause at 18.8%, Access Creation at 17.6%, and Bleeding at 12.5%. The registry entries do not identify these percentages as arm-specific comparative estimates, nor do they give the term-specific counts or denominators. They should therefore be read as entries in the registry’s serious-event list, not as evidence of a difference between study arms.
Serious adverse-event summaries describe events under the registry’s reporting categories; they do not by themselves show that an event was caused by a particular access approach. Definitions, ascertainment procedures, and event attribution are not reported in the registry record. The death fields in the group entries are null, so the serious-event listing does not supply a numerical mortality result.
12. What the Result Does, and Does Not, Mean
The registry record establishes the clinical question, the group definitions, and the stated outcome timeframe. It describes a prospective analysis of HeRO Graft access compared with a control group of evaluated patients who did not receive a HeRO Graft. Mortality is identified as the primary outcome over one year; infection, quality of life, intervention, and hospitalization are also listed as outcomes of interest.
What the registry entries do not establish is the size or direction of a mortality difference. Numerical mortality results, comparative estimates, uncertainty intervals, and p-values are not reported in the registry record. The same limitation applies to the other listed outcomes: their numerical comparative findings are not included in the registry record for this analysis. The serious-event percentages cannot be used to fill this gap because they are not described as between-arm estimates.
Even a reported difference between these groups would need cautious interpretation. The registry states that allocation is not stated, that the comparison is not randomized, and that the arms are not a like-for-like control comparison. Patients who receive a graft and those who do not may differ in ways related to their outcomes. Without reported baseline characteristics and an analysis plan, the extent to which measured or unmeasured differences affected comparisons cannot be judged.
The enrollment entry of 33 does not establish how many participants were included in each outcome analysis or completed the one-year follow-up. Those numbers, along with missing-data handling and the analysis population, are not reported in the registry record. Thus the study description can clarify what was intended to be compared, but it cannot support a conclusion about the magnitude, precision, or cause of any outcome difference.
This distinction is important: an endpoint definition is not an outcome result, and a completed study status does not disclose the results of its analyses. Statistical interpretation requires the estimates and their uncertainty, along with enough information about design and analysis to assess potential bias. Those elements are not present in the registry record.
13. Why This Trial Matters Statistically
This study addresses a practical comparative question in hemodialysis access: how outcomes in patients receiving a HeRO Graft compare with outcomes in patients who do not receive one. Its stated scope extends beyond mortality to infection, quality of life, interventions, and hospitalization. Considering multiple outcomes can give a broader view of what was evaluated, while also making transparent outcome definitions and analysis choices important.
Statistically, the registry’s description of the control group matters. It consists of patients evaluated but not receiving a graft for any reason, and the record explicitly says the arms are not a like-for-like comparison. This makes the distinction between association and causation central. Group contrasts in a nonrandomized study can reflect underlying differences between patients as well as any association with access type. Statistical methods can help describe or adjust observed differences, but the record does not report whether such methods were used or what information was available for adjustment.
The primary endpoint is a defined one-year mortality comparison, but the registry entries available do not include the numerical result or its precision. That illustrates why registration details and outcome estimates serve different purposes. A clear question and endpoint specify what a study aimed to assess; estimates and uncertainty are needed to judge what the data indicate. Without those results, the direction and magnitude of the mortality contrast cannot be evaluated.
The registry also lists several outcomes and analyses. Their interpretation depends on knowing which analyses were prespecified, how missing observations were handled, and whether multiplicity was considered. Those details are not reported. The study is therefore useful as a case for understanding how group selection, endpoint definition, outcome reporting, and analysis transparency shape the strength of a clinical comparison, rather than as a basis for a quantitative conclusion from the available record.
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 direct limitation is that numerical results for the primary mortality outcome are not reported in the registry record. There is no group-specific mortality percentage or comparative estimate, and no interval or p-value with which to assess precision or statistical evidence. The death fields in the serious adverse-event entries are null and do not resolve this absence.
The nonrandomized design is an additional limitation. The registry states that allocation is not stated and that the arms are not a like-for-like comparison. The control group includes patients who did not receive a HeRO Graft for any reason, but the reasons are not described. Baseline characteristics, clinical eligibility details, and procedures for assigning or selecting access are not reported in the registry record. Consequently, potential differences between groups and their influence on outcomes cannot be evaluated.
The record does not report how many participants contributed to each outcome, whether one-year follow-up was complete, or how missing observations were handled. It also does not define the analysis populations or state whether any analyses adjusted for participant characteristics. These omissions prevent assessment of the denominators and of possible bias from incomplete follow-up or analysis choices.
Further limitations concern outcome interpretation. The registry lists several outcomes and analyses but does not report a multiplicity strategy, outcome-specific methods, or detailed definitions and ascertainment procedures. Serious-event percentages are listed without term-specific counts, denominators, or an indication that they are arm-specific comparisons. They cannot be interpreted as causal effects or as replacements for the primary endpoint results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: HeRO Graft Compared to Permanent Catheters for End Stage Renal Disease (ESRD) Patients Receiving Hemodialysis — NCT01343251.
- Registry record last updated 2017-09-08; status last verified 2017-08.
- Results first posted 2016-03-14.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a completed prospective analysis, NCT01343251, comparing HeRO Graft access with a control group of evaluated patients who did not receive a graft. Enrollment is recorded as 33; the listed start and primary completion dates are 2011-01 and 2013-12. The primary outcome is mortality, described as the percentage of participants who died over one year. Infection, quality of life, intervention, and hospitalization are also listed as outcomes.
The record states that this was not a randomized comparison, allocation was not stated, and the arms were not a like-for-like control comparison. Numerical mortality results and comparative estimates are not reported in the registry record for this analysis. The registry lists serious adverse-event terms and group-level at-risk and affected counts, but these entries do not provide a primary mortality comparison. Analysis methods, missing-data handling, analysis populations, and multiplicity procedures are not reported in the registry record.