Utilization of Hepatitis C Positive Kidneys in Negative Recipients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Utilization of Hepatitis C Positive Kidneys in Negative Recipients (NCT03801707), a na phase 2, phase 3 study. The primary outcome is Proportion of Patients With Undetectable Hepatitis C Virus (HCV) Polymerase Chain Reaction (PCR) at 12 Weeks After Completion of HCV Treatment.

2. Clinical Question

In practical statistical terms, this is a feasibility and safety study with a primary question framed around a binary outcome: whether HCV PCR was undetectable at the specified follow-up point. It is not a comparative-effectiveness question, because the registered design does not include a concurrent comparator group. Secondary outcomes include estimated glomerular filtration rate, patient survival, and graft survival at 6 and 12 months after transplantation. Their inclusion indicates that the registry also tracked kidney function and survival, but their observed results are not reported in the registry record.

3. Trial Design

The registry identifies NCT03801707 as an open-label, single-group study. Its phase classifications are Phase 2 and Phase 3. Allocation is listed as not applicable, and masking is listed as none. The study is titled “Utilization of Hepatitis C Positive Kidneys in Negative Recipients”; its official title describes evaluating the feasibility and safety of kidney transplantation from HCV-positive donors into HCV-negative recipients.

The intervention group is described as kidney transplant recipients who received a kidney allograft from an HCV-viremic donor and then received direct-acting antiviral therapies. The registry lists sofosbuvir/velpatasvir and glecaprevir/pibrentasvir. It does not explain the treatment-selection procedure or provide participant-level treatment assignments. The lack of masking means the registered design was open-label; the record does not report additional procedures intended to conceal treatment or outcome information.

The registry lists an enrollment of 54. The study start date is 2019-03-22, primary completion is recorded as 2021-04-28, and the status is completed. These administrative details describe the registered study, but do not establish how many participants completed treatment or follow-up, or how many contributed to any particular outcome.

The primary outcome is undetectable HCV PCR 12 weeks after completion of HCV treatment. Secondary outcomes include estimated glomerular filtration rate at 6 and 12 months after transplantation, patient survival at those times, and graft survival at those times. The registry lists 5 outcome measures, but no analysis records. The protocol details, statistical analysis plan, and sample-size justification are not reported in the registry record. Because the study has no concurrent comparison group, its design can describe outcomes in the enrolled group but does not, by itself, provide a controlled estimate of a treatment effect relative to another strategy.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: In total 18 patients were removed from the study: 9 participants received hepatitis C virus nucleic antigen test (HCV NAT) negative kidney transplants, 8 participants were removed from the kidney transplant deceased waiting-list, and 1 participant died prior to receiving kidney transplant

Overall Study

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Proportion of Patients With Undetectable Hepatitis C Virus (HCV) Polymerase Chain Reaction (PCR) at 12 Weeks After Completion of HCV Treatment, measured over 12 weeks.

The primary endpoint is the proportion of participants with undetectable hepatitis C virus polymerase chain reaction (HCV PCR) 12 weeks after completion of HCV treatment. The underlying outcome is binary for each participant at that assessment: PCR is either reported as undetectable or it is not. The endpoint then expresses the group result as a proportion, which is intended to describe how frequently the specified virologic outcome occurred among participants assessed.

The registry says this outcome was intended to test treatment efficacy. A post-treatment PCR assessment is relevant to the study’s stated question because it evaluates whether HCV is detectable after the course of antiviral treatment has ended, rather than only during treatment. The specified follow-up interval also gives the endpoint a defined time point. The registry does not report the assay details, the threshold used to classify a PCR result as undetectable, or rules for handling missing or indeterminate tests.

No observed proportion, participant count, denominator, confidence interval, or hypothesis test for this endpoint is reported in the registry record. The enrollment of 54 should not be treated as the endpoint denominator: the record does not state how many participants completed treatment, had PCR measured at the target follow-up, or were included in the primary analysis. Without those results and analysis details, the endpoint definition can be explained, but the frequency and precision of the outcome cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a proportion describe?

General statistical explanation: a proportion is a count of participants meeting a defined condition divided by the number of participants assessed for that condition. For this trial, the condition is undetectable HCV PCR 12 weeks after completion of HCV treatment. The denominator should correspond to participants with an outcome assessed under the prespecified analysis rules. Total enrollment is not automatically the correct denominator, because some enrolled participants may not have an assessment at the relevant time. The registry does not report the primary endpoint count or denominator, so the observed proportion cannot be reconstructed from this record.

A proportion is an estimate for the group studied, not a guarantee that the same frequency would be observed in another group of participants. Its uncertainty depends in part on the amount of outcome information available and on the observed event frequency. A confidence interval is a range calculated by a statistical method to communicate uncertainty around an estimate. It is not a range containing a fixed share of individual participant outcomes, and it does not eliminate uncertainty about selection, measurement, or missing observations. No confidence interval for the primary endpoint is reported in the registry record.

What can a single-group design establish?

General statistical explanation: a single-group study estimates outcomes within the group enrolled and assessed. It does not contain a concurrent control group against which to estimate a between-group contrast. This design feature is especially important when interpreting a result as evidence of an intervention effect: observed outcomes can be described, but a contrast with an unobserved alternative is not directly estimated. Here, allocation is listed as not applicable, masking as none, and the model as single group. The registry does not report an analysis intended to create a comparative control from another source.

Open-label status describes the absence of masking in the registered design. It does not by itself show that an outcome assessment was biased. It does mean that the registry does not describe a masked study. The record does not report further information about outcome adjudication or safeguards against measurement bias, so such procedures should not be assumed.

What would uncertainty and testing contribute?

General statistical explanation: an estimate gives the magnitude of an observed result, while a confidence interval gives information about its precision under the assumptions of the chosen method. A hypothesis test, when prespecified and appropriately interpreted, evaluates compatibility of data with a stated statistical null hypothesis. A p-value is not the probability that a treatment is effective, nor does it measure the size or clinical importance of an effect. No primary endpoint estimate, confidence interval, or p-value is reported in the registry record. The statistical test, if any, is not reported in the registry record.

The registry identifies the primary outcome as a proportion, but does not describe whether the analysis would use a particular binomial method, an adjusted model, or another approach. General methods for binary outcomes can differ in how they calculate uncertainty, especially when the observed count is small or near a boundary. The record does not provide enough information to identify an analysis method or assess its assumptions. No particular method should be attributed to the study.

How should the planning illustrations be understood?

The sample-size assumptions described for planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is defined as a stated fraction of the observed effect. These are planning assumptions, not a description of the registered single-group study. The registry does not report that these assumptions were used to justify enrollment, and its own sample-size justification is not reported in the registry record. The illustrations are not observed power. In particular, they cannot compensate for the absence of a reported primary outcome estimate or establish what the study actually found.

General statistical explanation: power is a design-stage probability calculated under assumptions about the outcome, effect, variability, and analysis. Once a study is complete, a post hoc power calculation based on an observed effect does not replace direct reporting of the estimate and its uncertainty. Planning for a smaller effect than an observed estimate would require more participants under otherwise comparable assumptions, but no new sample-size values can be inferred without calculations and stated assumptions. The described two-arm planning framework also differs from the trial’s single-group structure.

Do the secondary outcomes call for different methods?

General statistical explanation: continuous outcomes such as estimated glomerular filtration rate are often summarized with a measure of location and variability, while survival outcomes require attention to follow-up time and censoring. The choice of method depends on the outcome definition, data availability, and analysis plan. The registry names estimated glomerular filtration rate and patient and graft survival at specified follow-up times, but does not report their observed values, distributions, censoring information, or analysis methods. It is therefore not possible to say which statistical procedures were used or whether their assumptions were met.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Intervention Group")
n      <- c(30)
events <- c(28)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Intervention Group  30  28  93.3  77.9  99.2  78.7  98.2  78.6  98.0

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary endpoint and lists secondary outcomes, but a detailed multiplicity strategy is not reported in the registry record. Multiplicity arises when several outcomes or statistical tests are considered: the more questions examined, the greater the chance that at least one result may appear notable by chance if each is interpreted without regard to the others. General statistical approaches can control or describe this issue, but the record does not say whether any adjustment or hierarchy was planned. No analysis records are listed.

The registry lists 5 outcome measures. The named secondary outcomes include estimated glomerular filtration rate at 6 and 12 months after transplantation, patient survival at 6 and 12 months, and graft survival at 6 and 12 months. Their listing alone does not establish that every outcome was measured for every participant, analyzed, or reported. The analysis plan and any rules for interpreting multiple outcomes are not reported in the registry record.

Missing-data handling is also not reported in the registry record. There is no reported primary endpoint denominator, account of missing PCR measurements, or description of how participants without a target-time assessment were handled. The registry does not state whether analyses used all enrolled participants, participants who completed treatment, participants with an available assessment, or another analysis population. These distinctions can affect the interpretation of a proportion because the participants contributing to the numerator and denominator need to be clear.

The registry’s enrollment count is 54, while the adverse-event record lists 30 participants at risk in each of its reported categories. The record does not explain the relationship among these counts or establish that any one is the analysis population for the primary endpoint. Without participant flow, missing-data rules, and analysis-population definitions, completeness and selection of the outcome data cannot be assessed.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The adverse-event record lists 30 participants at risk for serious adverse events, with 0 affected, and 30 at risk for other adverse events, with 2 affected. It also lists 0 deaths. No serious adverse event terms are listed. These are the registry’s posted counts; the record does not provide event descriptions for the two participants in the other-adverse-event category.

Serious adverse events and other adverse events are separate categories in the record and should not be combined or treated as interchangeable. The “at risk” counts indicate the denominators associated with those categories in the adverse-event entry; the record does not explain why these denominators are 30 when overall enrollment is 54, or whether the same participants contributed to both categories. The counts should not be interpreted as applying to all enrolled participants without further information.

Counts alone do not describe timing, duration, severity within the non-serious category, relationship to transplantation or antiviral treatment, or how events were collected. The record does not report those details. A count of 0 affected participants for serious adverse events is the posted observation for the listed group and denominator; it is not proof that the risk of a serious event is absent. Likewise, 0 recorded deaths does not establish a broader survival result beyond the registry’s posted count. The safety figures should be read as limited descriptive information, not as a comparison or a complete characterization of safety.

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

The registry entry defines a clinically relevant research question: whether HCV PCR was undetectable at a specified interval after antiviral treatment among HCV-negative recipients of kidneys from HCV-viremic donors. It also records a completed, open-label, single-group study with an enrollment of 54. These details describe the study’s intended population, intervention, and design. They do not provide the primary outcome result.

Because the primary endpoint’s observed count and denominator are not reported in the registry record, no conclusion about the frequency of undetectable PCR can be drawn from this entry. There is no reported estimate or confidence interval to indicate its precision. The missing result should not be interpreted as either a favorable or unfavorable outcome. The registry also does not report numerical results for the listed kidney-function, patient-survival, or graft-survival outcomes.

The study’s single-group design places a further boundary on interpretation. If outcome results were available, they could describe what occurred among assessed participants in this group. Without a comparator, they would not directly quantify how those outcomes differed from a separate group receiving another strategy. The registered design therefore does not support a controlled between-group treatment-effect estimate.

The posted adverse-event counts offer limited safety information for the participants listed at risk: 0 affected by serious adverse events among 30 at risk, 2 affected by other adverse events among 30 at risk, and 0 deaths. The record does not provide event details or explain how these denominators relate to the total enrollment. These counts do not, on their own, establish the frequency of events in all enrolled participants or permit comparisons with another group.

Overall, the entry supports an account of the study question and design, and a narrow description of the posted safety counts. It does not establish the primary outcome’s magnitude, its precision, or comparative effects. Further outcome and analysis details are not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable because it asks a clearly defined post-treatment question in a population described by both donor and recipient HCV status. The endpoint has a specific measurement and timing: undetectable HCV PCR 12 weeks after completion of treatment. A defined endpoint makes clear what the study intended to measure, even though the registry does not report the result needed to estimate its frequency.

The single-group design also illustrates the distinction between describing an outcome and estimating a comparative effect. A study can document outcomes among participants who received a particular transplant-and-treatment approach. Without a concurrent comparator, however, the design does not estimate how those outcomes differ from an alternative group under the same study conditions. That is a limitation of the comparison structure, not a judgment about the observed outcomes.

For biostatistical interpretation, the gap between enrollment and the available outcome denominators is important. The registry lists 54 enrolled participants, but does not give the primary endpoint denominator, while the adverse-event entry lists 30 at risk in each safety category. Transparent participant flow and explicit analysis populations would help readers understand which participants contribute to each result. Those details are not reported in the registry record.

The entry also shows why a named endpoint is not equivalent to a reported finding. Without the event count, denominator, and uncertainty estimate, readers cannot assess the magnitude or precision of the primary result. Nor can planning assumptions substitute for observed data: the stated sample-size illustrations are planning exercises, not observed power or evidence about the result. The statistical value of the registry entry is therefore chiefly in its documented question and design, together with a limited set of safety counts, rather than in an evaluable estimate of the primary outcome.

15. 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 principal trial-specific limitation for interpreting this registry entry is that it does not report the primary endpoint result. The outcome definition is present, but its count, denominator, estimate, and uncertainty are not. The listed enrollment of 54 cannot be assumed to be the primary analysis denominator because participant completion and assessment status are not reported.

The single-group design has no concurrent control group, and the registry lists allocation as not applicable. As a result, the design does not provide a direct comparison with another donor source or treatment strategy. The study is open-label, with masking listed as none. The registry does not describe outcome-assessment procedures that might clarify how potential knowledge of treatment was addressed.

The registry lists two antiviral drug interventions but does not report which participants received each drug, how treatment choice was made, or whether treatment courses differed. It also does not report assay details or classification rules for an undetectable PCR result. Without these details, readers cannot assess how consistently the primary endpoint was measured or how intervention exposure varied within the group.

Participant flow, missing-data handling, analysis populations, and statistical methods are not reported in the registry record. The relationship between total enrollment and the adverse-event denominators is also unexplained. Although several secondary outcomes are named, their results and analysis procedures are not reported. A multiplicity strategy and a sample-size justification are not reported in the registry record. These omissions limit assessment of precision, completeness, possible selection in the analyzed group, and the interpretation of outcomes across the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Utilization of Hepatitis C Positive Kidneys in Negative Recipients — NCT03801707.
• Registry record last updated 2023-09-13; status last verified 2023-08.
• Results first posted 2023-09-13.
• 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.

19. Record Summary

NCT03801707 is a completed, open-label, single-group study registered as Phase 2 and Phase 3, with an enrollment of 54. It evaluated kidney transplantation from HCV-viremic donors into HCV-negative recipients followed by direct-acting antiviral therapy. The registry lists sofosbuvir/velpatasvir and glecaprevir/pibrentasvir.

The primary endpoint was the proportion with undetectable HCV PCR 12 weeks after completion of HCV treatment. Secondary outcomes included estimated glomerular filtration rate, patient survival, and graft survival at 6 and 12 months after transplantation. The registry does not report numerical results for these outcomes or analysis records.

The adverse-event entry lists 0 serious adverse events among 30 participants at risk, 2 participants with other adverse events among 30 at risk, and 0 deaths. Further event details and the relationship between these denominators and total enrollment are not reported in the registry record. The primary outcome denominator, missing-data procedures, analysis populations, statistical methods, and sample-size justification are also not reported.