Study Evaluating The Use Of Sirolimus In Recipients Of Kidney Allografts From Expanded Criteria Donors (ECD): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study Evaluating The Use Of Sirolimus In Recipients Of Kidney Allografts From Expanded Criteria Donors (ECD) (NCT00697112), a registered phase not stated study. The primary outcome is Percentage of Participants With Main Reason for the Use of Sirolimus (Rapamune) Therapy.

2. Clinical Question

The registry’s purpose was to examine clinical outcomes associated with sirolimus use under routine-practice conditions and to identify the criteria or reasons for choosing it in this selected population. It also aimed to describe emerging patterns of immunosuppressive treatment involving sirolimus. These are descriptive questions about clinical decision-making and treatment patterns. They do not, by themselves, establish whether sirolimus caused an outcome or was better or worse than another treatment.

The study enrolled 53 participants and is recorded as completed. Its start is listed as 2008-05 and its primary completion as 2012-12. Those dates describe the registry record; they do not supply the missing outcome results. The main reason for treatment was assessed at baseline, while several listed secondary outcomes concern graft survival, rejection, participant survival, medication dosing and levels, creatinine clearance, proteinuria, and premature discontinuation. Results for those outcomes are not reported in the registry record.

3. Trial Design

This was an observational study of sirolimus use in recipients of kidney allografts from expanded criteria donors. Its stated setting was routine clinical practice. The intervention is listed as the drug sirolimus, and the described purpose was to observe treatment and clinical outcomes rather than to assign participants to competing therapies. The registry record does not describe a randomized allocation or a control group; it explicitly cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison.

The enrollment was 53, and the status is completed. The primary objective was to identify current criteria or reasons for using sirolimus as base therapy in this selected population and to understand emerging immunosuppressive treatment patterns. The main endpoint uses a physician-selected reason, recorded with a questionnaire at baseline. The physician responsible selected one criterion as the main medical reason for introducing sirolimus after renal transplant.

The primary-outcome population is described as intention-to-treat and includes all participants treated with Rapamune for at least 4 or 5 weeks. That phrasing leaves the precise duration threshold unclear. The registry does not report the number of participants included in the primary analysis, nor does it explain exclusions or departures from the stated population.

Listed secondary outcomes include probabilities of graft survival, no acute rejection, and participant survival; average doses and blood levels of immunosuppressive drugs; average creatinine clearance and proteinuria; and the percentage who prematurely discontinued sirolimus therapy. The registry lists 21 outcome measures overall, but records 0 analyses. Numerical outcome estimates, analysis populations for secondary outcomes, and methods for those outcomes are not reported in the registry record. The record also does not report a sample-size justification or a detailed statistical analysis plan.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intention-to-Treat (ITT) population included all participants who were treated with Rapamune for at least 4 or 5 weeks.

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: Safety population included all participants who had received at least 1 dose of Rapamune and were subsequently interrogated.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With Main Reason for the Use of Sirolimus (Rapamune) Therapy, measured over Baseline.

The primary endpoint is the percentage of participants with each main reason for using sirolimus therapy, measured at baseline. A questionnaire included different clinical criteria. The responsible physician selected the criterion considered the main medical reason for introducing sirolimus as base immunosuppressive therapy after renal transplant. The endpoint therefore describes the clinician’s stated reason, rather than a participant health outcome or a comparison of treatments.

This measure is useful for a descriptive objective: it can characterize the decision-making criteria recorded for sirolimus use in this selected group under routine clinical practice. Because the physician selects a single main reason, the measure represents a prioritized reason, not necessarily every consideration that affected the decision. The registry description does not list the available criteria or explain how the questionnaire was administered beyond that selection process.

The unit is percentage of participants, and the endpoint specifies a 95% confidence interval. A confidence interval communicates uncertainty around an estimated percentage; it does not establish that the estimate is free of selection or measurement limitations. No percentage, confidence-interval limits, or number of participants contributing to the primary result is reported in the registry record. Consequently, the relative frequency of the different reasons cannot be described from the record.

The stated primary-outcome population includes participants treated with Rapamune for at least 4 or 5 weeks. The record does not clarify that wording or report how it was applied. It also does not report whether the primary measure was available for every participant in that population.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry is limited. It specifies a percentage endpoint with a 95% confidence interval but does not report the interval calculation method, numerical estimates, or a statistical analysis plan. The registry lists 0 analyses. The explanations below describe general statistical concepts and do not imply that a particular method was used for this study.

What does a percentage measure?

General: a percentage expresses the share of an analysis population that falls into a stated category. For this primary endpoint, the categories are the physicians’ selected main reasons for introducing sirolimus. To interpret a percentage, a reader needs to know both the category definition and the number of participants with usable data in the denominator. The record describes the selection process and the intended population, but does not report the resulting category counts or denominator for the primary result.

The physician selected one reason as the main reason. This makes the endpoint a summary of recorded priorities. It should not be interpreted as a complete inventory of every clinical consideration, nor as an objective measurement of the participant’s clinical state. The registry does not list the questionnaire categories, so their breadth and wording cannot be assessed from the record.

What does a confidence interval convey?

General: a confidence interval gives a range of values compatible with an estimate under a specified statistical procedure. A narrower interval generally indicates greater statistical precision, while a wider interval indicates greater uncertainty. The interval does not remove possible bias from participant selection, incomplete recording, or subjective classification. Its interpretation also depends on the method used to calculate it.

The primary endpoint specifies a 95% confidence interval, but the registry does not report its limits or calculation method. It is therefore not possible to assess the precision of the estimated percentages or to determine whether the interval method accounted for features of the data. A stated confidence level alone does not provide the result.

Why does the observational design matter?

General: in an observational study, treatment choice is not created by random assignment. Reasons for choosing a treatment can be related to patient characteristics, clinical judgments, or care context. Those same factors may also relate to outcomes. This is one source of confounding: an observed association may reflect differences between people or circumstances rather than an effect of treatment itself.

The registry describes sirolimus use in routine clinical practice and provides no like-for-like control comparison. The record does not report adjustment methods or analyses that would address confounding. Accordingly, the study’s stated descriptive objective should not be confused with a randomized estimate of treatment effect.

What is the role of analysis populations?

General: an analysis population defines which participants contribute to a particular estimate. The registry describes the primary population as intention-to-treat and says it includes participants treated with Rapamune for at least 4 or 5 weeks. The wording is not fully precise, and the record does not state the number who met the definition or contributed primary endpoint data. Those details matter because a percentage depends on its denominator. The record also does not report analysis populations for the secondary outcomes.

What can be concluded from the listed outcomes?

The registry names secondary measures involving survival, rejection, immunosuppressive medication, creatinine clearance, proteinuria, and treatment discontinuation. Naming an outcome does not establish that a numerical result was reported. Here, the record lists 21 outcome measures but 0 analyses. No estimate, uncertainty interval, or inferential result for those secondary measures is reported in the registry record.

General: time-to-event outcomes, such as survival, are often analyzed with methods that use both event timing and follow-up. A probability of survival at a specified time is interpretable only with the relevant time point, analysis population, and handling of censoring. The registry’s list names probabilities of graft and participant survival, but the numerical results and analysis details are not reported.

General: over-dispersion matters when count data vary more than a model assumes; ignoring it can make uncertainty estimates too small. The available primary endpoint is a percentage, and the record does not report a count model or an over-dispersion assessment. No such method should be presumed. More broadly, methods should be matched to the outcome type and reported with enough detail to evaluate their assumptions.

The record does not report p-values, adjusted estimates, covariate choices, or a multiplicity procedure. There is no basis for reconstructing an analysis from the endpoint descriptions alone. Any numerical interpretation beyond the stated enrollment and safety figures would require results that are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 21 outcome measures, including the primary reason-for-use measure and secondary measures spanning survival, rejection, drug use, kidney-function measures, proteinuria, and treatment discontinuation. It records 0 analyses. The registry record does not report a multiplicity plan, such as whether any procedure was used to account for examining several outcomes. Without reported analyses and a stated plan, the possibility of selective emphasis among multiple results cannot be evaluated.

Missing-data methods are not reported in the registry record. The primary population is described as participants treated with Rapamune for at least 4 or 5 weeks, but the exact application of that duration criterion is unclear. The record does not state how many participants had a recorded primary reason, whether questionnaire responses were missing, or how missing outcome observations were handled. It also does not report missingness for the listed secondary outcomes.

These gaps matter because an estimate depends on who contributes data and how unavailable observations are treated. If participants without recorded outcomes differ from those with recorded outcomes, the observed percentage or clinical-outcome estimate may not represent the intended population. This is a general concern, not a claim that missingness occurred in this study.

The registry does not report a statistical analysis plan, interim analyses, or a sample-size justification. Those details cannot be inferred from the completed status or enrollment. No p-values or adjusted analyses are reported. The record therefore does not allow assessment of planned versus completed analyses, outcome-specific denominators, or whether any inferential findings account for multiple comparisons.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: escherichia urinary tract infection (3.8%), urinary tract infection (3.8%), renal failure (3.8%), renal failure acute (3.8%), pneumonitis (3.8%).

The registry reports 52 participants at risk in the serious adverse-event category, with 21 affected. It also reports 52 at risk in the other adverse-event category, with 42 affected. These are descriptive counts in the sirolimus group, not a comparison against a control group. The record does not provide a comparative estimate or enough information to attribute events to treatment.

The listed top serious-event terms are Escherichia urinary tract infection, Urinary tract infection, Renal failure, Renal failure acute, Pneumonitis, and Transplant rejection. Each is reported as 3.8%. These are the registry’s listed terms and percentages; the record does not provide further detail about event timing, duration, severity beyond the serious-event classification, or overlap between terms. The percentages should not be added together, since the record does not establish that the categories are mutually exclusive.

The death count is not reported in the registry record. The serious-event counts and listed terms do not establish a rate relative to another therapy, and they do not determine whether an event was caused by sirolimus. They should be read as recorded safety information for the observed group, with the limitations of the registry design and reporting detail.

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

The record establishes that a completed observational registry examined sirolimus use among kidney allograft recipients from expanded criteria donors. Its primary objective was descriptive: to identify physicians’ main reasons for introducing sirolimus as base immunosuppressive therapy and to understand treatment patterns in routine clinical practice. It specifies a baseline percentage endpoint and a 95% confidence interval.

However, the record does not report the primary percentages or their confidence intervals. It also does not report analyses for the listed secondary outcomes. The registry’s descriptions therefore clarify what was intended to be measured, but they do not show the distribution of treatment rationales or the clinical outcome estimates. The safety counts and serious-event terms are the reported numerical safety information, and those are descriptive rather than comparative.

The observational design and absence of a like-for-like control group limit causal interpretation. Even if outcome estimates were available, this design alone would not establish that sirolimus caused an observed outcome or that it performed better or worse than another treatment. The record does not describe adjustment analyses that could address differences related to treatment selection.

These limits do not mean that the study had no value. Descriptions of prescribing rationale and treatment patterns can help characterize practice in the selected population. But such descriptive evidence answers a different question from whether a therapy causes a benefit or harm. The record also does not report enough information to evaluate the precision of the primary estimate, the handling of missing data, or the analysis of multiple outcomes.

The appropriate reading is therefore narrow: the registry documents the study’s objectives, design context, endpoint definition, and certain safety counts. It does not provide the primary or secondary outcome results needed to draw conclusions about how common each reason was or how the clinical outcomes were distributed. No treatment recommendation follows from the information reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically notable because its primary objective concerns clinical decision-making rather than a randomized treatment contrast. The endpoint records the responsible physician’s selected main reason for introducing sirolimus. Such a measure can describe practice patterns in the study population, but it is not itself a measure of treatment effect. Keeping that distinction clear is important when reading observational research.

The endpoint is expressed as a percentage and specifies a 95% confidence interval. This makes the intended result a set of category-specific estimates with uncertainty, rather than a single comparison between treatment groups. Yet neither the estimates nor the interval limits are reported. The study illustrates why an endpoint definition and a confidence-level specification are not substitutes for the actual results and analysis details.

Its routine-practice setting is relevant to the descriptive question, while the absence of a like-for-like comparator constrains causal interpretation. In observational studies, treatment choices may reflect clinical circumstances that also relate to outcomes. Statistical adjustment can sometimes address measured differences, but the record does not report whether such methods were used. The design and analysis information must therefore be kept separate from any assumption about treatment effects.

The registry lists 21 outcome measures but 0 analyses. That gap is consequential: readers cannot evaluate estimates, precision, analysis populations, or how multiple outcomes were handled. The safety counts offer some descriptive information, but do not create a comparative safety estimate. This record thus demonstrates the importance of complete reporting: clear results, denominators, uncertainty, missing-data handling, and analysis methods are needed to interpret a study beyond its stated aims.

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 of the registry record is that it describes the study objectives and outcome measures without reporting the primary outcome estimates. No percentages for physicians’ selected reasons or confidence-interval limits are reported. Numerical results for the listed secondary outcomes are also not reported, despite 21 outcome measures being listed and 0 analyses being recorded.

The population definition for the primary outcome is phrased as participants treated with Rapamune for at least 4 or 5 weeks. The record does not clarify the intended threshold, report the number meeting it, or give the primary analysis denominator. It also does not state whether all eligible participants had a recorded physician-selected reason.

The observational design has no described like-for-like control group, and the registry cautions that this was not a randomized comparison. The record does not report adjustment methods or a statistical analysis plan. It therefore cannot support a causal or comparative conclusion. The registry’s stated setting of routine clinical practice also does not, on its own, show how representative the enrolled population was.

Further details are not reported about missing-data handling, multiplicity, interim analyses, or sample-size justification. For safety, the record gives affected counts and selected serious-event terms, but does not report deaths or provide context sufficient for comparative interpretation. These are limits of what the registry record reports; they should not be mistaken for evidence that particular analyses or events did or did not occur.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study Evaluating The Use Of Sirolimus In Recipients Of Kidney Allografts From Expanded Criteria Donors (ECD) — NCT00697112.
• Registry record last updated 2014-01-22; status last verified 2013-12.
• Results first posted 2014-01-22.
• 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.

18. Record Summary

NCT00697112 is a completed observational study of sirolimus use in kidney allograft recipients from expanded criteria donors. Enrollment was 53. The study’s primary objective was to identify the main physician-reported reason for introducing sirolimus as base immunosuppressive therapy and describe treatment patterns under routine clinical practice.

The primary endpoint is the baseline percentage of participants assigned each main reason, with a specified 95% confidence interval. Its population is described as participants treated with Rapamune for at least 4 or 5 weeks. The record lists 21 outcome measures and 0 analyses, but does not report the primary percentages, confidence intervals, or secondary outcome results.

Safety information includes 21 affected among 52 at risk in the serious-event category and 42 affected among 52 at risk in the other-event category. Six serious-event terms are listed at 3.8% each. The registry describes no like-for-like control comparison, so these figures are descriptive rather than comparative.