Self-sampling for Human Papillomavirus (HPV) Among Patients Receiving Colposcopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Self-sampling for Human Papillomavirus (HPV) Among Patients Receiving Colposcopy (NCT04585243), a na na study. The primary outcome is Number of Participants With Concordance of Screening Results of the Self-Sampling Kit Compared to Clinician-collected Samples.

2. Clinical Question

The study also set out to assess whether participants completed self-sampling kits, whether they reported problems using them, and what barriers they faced in cervical cancer screening. The registry describes these as secondary outcomes or study aims, but does not report numerical results for them.

The central statistical issue is agreement across different collection or assessment methods. Concordance can describe whether results match, but interpretation depends on how a match was defined and how each measure was handled. Those details are not reported in the registry record. The record also does not state how many participants contributed paired results for each comparison.

This question is distinct from whether self-sampling is equivalent to clinician sampling in a randomized comparison. The study is listed as single-group, with allocation recorded as NA and masking as none. Its design, as described, concerns the experience and observed agreement of self-sampling in a colposcopy setting. The registry record does not report outcome estimates that would answer how often results agreed or how precisely agreement was estimated.

3. Trial Design

NCT04585243 is a single-group study titled “Self-sampling for Human Papillomavirus (HPV) Among Patients Receiving Colposcopy.” The official title identifies the Penn State Hershey Colposcopy Clinics. Milton S. Hershey Medical Center is listed as sponsor. The intervention is the Evalyn Brush self-sampling kit, described as being mailed to participants for sample collection for HPV and cervical cancer screening.

The registry lists allocation as NA and masking as none. It does not describe a randomized allocation or a masked comparison. Clinician-collected HPV testing, Pap smear results, and colposcopy appear as measures against which self-sampling results were to be compared; they should not be interpreted as randomized treatment arms. The record identifies the study model as single-group, so between-arm treatment-effect language would not fit this design.

Recorded enrollment is 22. The study began on 2020-12-09, and primary completion is recorded as 2022-09-30. Its status is terminated. The registry record does not explain the reason for termination, so no explanation should be inferred from the status alone.

The primary outcome is the number of participants with concordant screening results between self-sampling and clinician-collected samples, with the description also naming Pap smear results and colposcopy. Its timeframe is within two weeks of the colposcopy exam. Secondary outcomes include the number of completed self-sampling kits and the number of participants reporting problems using them. The study summary also describes acceptability and screening barriers as aims.

The registry record lists 3 outcome measures and 0 analyses. That does not establish what analyses may have been conducted outside the registry; it means that analysis results and details are not reported in the record. Protocol details such as eligibility criteria, recruitment procedures, and the analysis plan are not reported in the registry record.

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

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 Number of Participants With Concordance of Screening Results of the Self-Sampling Kit Compared to Clinician-collected Samples, measured over Within two weeks of their colposcopy exam..

The primary endpoint counts participants with concordance between screening results from the self-sampling kit and clinician-collected samples. The outcome description also names Pap smear results and colposcopy as comparators. The timeframe is within two weeks of the colposcopy exam. The stated endpoint is a count of participants, rather than a reported percentage or a measure of test sensitivity or specificity.

Concordance is used to describe agreement between methods or assessments. In general, agreement is relevant when evaluating whether two approaches produce the same classifications or findings. It does not, by itself, establish which approach is correct. A measure of accuracy requires a defined reference standard and a suitable analysis of results relative to that standard. The registry record does not report such an accuracy analysis.

The endpoint could help describe whether self-sampling results matched the named clinician-collected or clinical results, but the record does not state the exact rule for declaring a match. It also does not report the count of concordant participants, the number with paired results, or uncertainty around any estimate. The results therefore cannot be interpreted as showing the level or precision of agreement.

Because this outcome is a count, its meaning depends on the number of participants with evaluable results. The recorded enrollment does not establish that every enrolled participant completed self-sampling or had all comparison measures available. Completion and missing-result details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The main statistical concept in this study is concordance: whether two or more ways of collecting or assessing screening information produce matching results. The primary outcome is described as a count of participants with concordant results. The record names self-sampling, clinician-collected HPV testing, Pap smear results, and colposcopy, but does not specify exactly which pairs or combinations were used to define concordance. It also does not state the rule for classifying results as matching.

What does concordance measure?

In general, concordance summarizes agreement, not necessarily accuracy. Two methods can agree with each other without either being correct. To assess accuracy, an analysis needs a defined reference standard and an explicit comparison of results against that standard. The registry record does not identify a formal reference standard or report an accuracy estimate. The study summary uses accuracy as an aim, but the primary outcome description is a participant count for concordance.

Agreement can be reported in more than one way. A count conveys the number of participants meeting a stated agreement rule; an agreement proportion would also require a denominator, such as the participants with paired, interpretable results. Adjusted agreement measures may account for agreement expected by chance, but the registry record does not state that such a measure was planned or calculated. No agreement estimate, denominator, or uncertainty interval is reported.

Why does the single-group design matter?

The study is listed as single-group, with allocation NA and masking none. This design description does not set up a randomized comparison between a self-sampling arm and a control arm. Instead, the stated primary question compares results from self-sampling with clinician-collected or clinical measures. These are paired or related measurements in the study question, not independent randomized groups. Analyses should therefore be interpreted as agreement assessments, not as evidence of a randomized intervention effect.

The registry record does not describe whether the planned comparisons used paired data, how discordant results were handled, or whether different comparator results were analyzed separately. Those choices affect what an agreement estimate means. They are not reported in the registry record and should not be assumed.

What does a confidence interval add?

In general, a confidence interval describes the uncertainty around an estimate under the assumptions of the analysis. An estimate based on limited evaluable information may be imprecise, even if its point estimate appears clear. A narrow interval indicates greater precision under the model; a wide interval indicates more uncertainty. No confidence interval or other precision measure for the primary outcome is reported in the registry record, so the precision of observed concordance cannot be assessed.

What does over-dispersion mean in general?

For count outcomes, a statistical model may assume a particular relationship between the mean and variability. Over-dispersion means the observed variability is greater than that assumed by a model. If present and not addressed, standard errors and confidence intervals can be too small, making results appear more precise than they are. Whether over-dispersion is relevant depends on the specific model and data structure. The registry record does not report a count model or a dispersion assessment, so it is not possible to say that either was used or needed.

The outcome is a count of participants, and the record does not provide a model or analysis details. A simple count does not by itself describe a rate or probability unless its denominator is defined. The record also does not report outcome-specific evaluable counts, missing-result handling, or whether any adjustment was planned. No statistical test, effect estimate, or p-value is listed.

How should planning illustrations be read?

General sample-size planning illustrations describe hypothetical future-study requirements under stated assumptions; they are not observed study results. The record describes the illustrations as based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the illustration uses total events; other illustrations use participants per arm. These are planning assumptions, not the design of this single-group study and not evidence of observed power.

The registry record does not report the observed effect needed to interpret such illustrations, nor numerical planning outputs. The illustrations therefore cannot be treated as evidence about the study's achieved precision or power. Sample-size calculations are planning tools, not a substitute for reporting outcome data and uncertainty.

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("Participants")
n      <- c(12)
events <- c(8)
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  Participants  12  8  66.7  34.9  90.1  39.1  86.2  38.6  86.1

11. Multiplicity, Missing Data and Analysis Populations

The study has a primary concordance outcome and secondary outcomes concerning completed self-sampling kits and reported problems using kits. The summary also identifies acceptability and barriers to screening as aims. The registry record lists 3 outcome measures and 0 analyses, but it does not report a statistical analysis plan describing how these outcomes were to be analyzed.

Multiplicity arises when several outcomes or comparisons are examined. In general, the more analyses considered, the more important it is to distinguish the primary question from secondary or exploratory questions and to state whether any adjustment or prioritization was planned. The registry record does not report a multiplicity strategy, a hierarchy among comparisons, or an adjustment for multiple testing. It is therefore not possible to determine how results across outcomes would have been interpreted together.

Missing-data handling is also not reported in the registry record. The record does not state whether participants who did not return a kit, had an unusable sample, or lacked a clinician-collected comparison were included in any analysis, or how incomplete paired results were to be handled. These details matter because the primary outcome requires comparison between results. The recorded enrollment does not reveal the outcome-specific denominators.

Analysis populations are not described. The registry record does not say whether analyses were intended for all enrolled participants, only participants who returned a kit, or participants with complete comparison results. It also does not report a protocol-defined analysis population or a plan for deviations from study procedures. With no analyses listed and no outcome estimates reported, conclusions about missingness, exclusions, or analysis populations cannot be drawn.

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.

The registry record lists safety counts for a group titled Participants. It reports 12 participants at risk for serious adverse events and 0 affected. For other adverse events, it reports 12 participants at risk and 0 affected. Deaths are recorded as 0. These are the safety figures reported in the registry record.

Counts of zero mean that no affected participants or deaths are listed in those registry entries. They do not establish that an event was impossible, nor do they establish that the intervention has no safety risks. Safety counts should be read in the context of the study’s size, observation, and reporting, but duration of safety follow-up and event-collection procedures are not reported in the registry record.

The registry does not provide a description of the safety-monitoring process, event definitions, or a detailed account of how adverse events were collected. It also does not list serious adverse event terms. The figures should therefore be understood as the recorded counts, not as a complete characterization of safety or a comparison with another group. This single-group study has no randomized control arm in the registry description.

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

The registry record establishes that NCT04585243 was designed to examine HPV self-sampling with the Evalyn Brush kit in a colposcopy setting. It identifies concordance with clinician-collected HPV testing and other clinical measures as the primary outcome, and it names kit completion and reported problems as secondary outcomes. It also records enrollment of 22 and a terminated status.

The record does not report the primary concordance count or the number of participants with paired results. It therefore does not show how often self-sampling results matched clinician-collected or other named results. It also does not report a measure of accuracy, a confidence interval, or a statistical analysis of agreement. The study description alone cannot establish whether the kit was accurate, acceptable, feasible, or a viable alternative to clinician collection.

Likewise, no numerical results for kit completion, problems using kits, acceptability, or screening barriers are reported in the registry record. The absence of these results in the record should not be interpreted as a zero count or as evidence that participants experienced no difficulties.

The design is single-group and not described as randomized. Its comparison measures do not create a randomized control group, so the study description does not support causal conclusions about treatment effects. The registry status of terminated does not explain why the study ended, and it should not be used to infer whether the study question was answered.

In general, a useful interpretation of a concordance study requires the agreement definition, outcome-specific denominators, numerical estimates, and an account of uncertainty. Those details are not reported in the registry record. The appropriate conclusion is therefore limited: the registry describes the question and planned outcomes, but does not provide the results needed to judge the degree or precision of agreement.

14. Why This Trial Matters Statistically

This study raises a practical statistical question: whether a self-collected sample produces screening results that agree with results from clinician collection and other clinical assessments. Agreement is an important measurement property when different collection approaches are being considered. It can help characterize how measurements relate in a specific setting, while leaving separate questions about accuracy, acceptability, and feasibility to be addressed with suitable outcome definitions and data.

The colposcopy setting is central to the scope of the question. The study is described among patients receiving colposcopy at the Penn State Hershey Colposcopy Clinics, and the primary outcome is tied to results within two weeks of the colposcopy exam. The registry record does not report whether findings would apply to other settings or populations, so the stated context should guide interpretation.

Statistically, the single-group design highlights the distinction between paired measurement comparisons and randomized treatment comparisons. A self-sampling result can be compared with another measure without creating a control arm. The resulting agreement evidence, if reported, would answer a different question from a trial estimating a between-group treatment effect.

The record also illustrates why outcome definitions and denominators matter. A count of concordant participants is difficult to interpret without knowing who had paired, interpretable results and how concordance was defined. Precision matters as well: an estimate without an uncertainty measure can leave substantial ambiguity about the range of agreement compatible with the data.

Here, the registry record identifies the intended outcomes and design but lists no analyses and reports no outcome estimates. That makes the reporting gap itself important: the study rationale cannot substitute for results. A reader needs the observed counts, denominators, analytic definitions, and uncertainty to assess what the study contributes.

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 primary limitation for interpretation is that numerical results for the primary and secondary outcomes are not reported in the registry record. The record lists 0 analyses, so it does not provide concordance estimates, kit-completion findings, reported problems, or results for acceptability and screening barriers. The planned question cannot be answered from the registry information alone.

The primary outcome description does not specify the operational definition of concordance. It names clinician-collected HPV testing, Pap smear results, and colposcopy, but does not report whether each was assessed separately or how a match was determined. The record also does not report the number of participants with complete paired data for any comparison.

Recorded enrollment is 22, but enrollment is not an outcome-specific denominator. The record does not provide kit return rates, unusable-sample counts, missing comparison results, exclusions, or analysis populations. The effect of incomplete data on any potential estimate cannot be assessed.

The study is listed as single-group, with allocation NA and masking none. The record does not describe a randomized comparison, so it cannot support a randomized between-arm effect estimate. Further design details, eligibility criteria, recruitment methods, and protocol procedures are not reported in the registry record.

The study status is terminated, but the reason is not reported. The registry record also does not give the analysis plan, multiplicity approach, or method for estimating uncertainty. These omissions prevent assessment of possible selection, measurement, and analysis issues. They do not establish that a particular bias occurred; they limit what can be concluded from the available record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Self-sampling for Human Papillomavirus (HPV) Among Patients Receiving Colposcopy — NCT04585243.
• Registry record last updated 2023-10-11; status last verified 2023-10.
• Results first posted 2023-09-22.
• 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.

19. Record Summary

NCT04585243, “Self-sampling for Human Papillomavirus (HPV) Among Patients Receiving Colposcopy,” is a terminated, single-group study sponsored by Milton S. Hershey Medical Center. The intervention was the Evalyn Brush self-sampling kit. Recorded enrollment is 22; the study began on 2020-12-09, with primary completion recorded as 2022-09-30.

The primary outcome is the number of participants with concordance between self-sampling and clinician-collected or other named clinical results, within two weeks of the colposcopy exam. Secondary outcomes concern completed kits and reported problems using kits. The registry lists 3 outcome measures and 0 analyses. It does not report numerical outcome results or explain the reason for termination.

The registry lists 0 serious adverse events, 0 other adverse events, and 0 deaths, with 12 participants at risk recorded for each adverse-event category. These counts should be read as registry entries, not as proof that risk was absent.