Zenyth: Motivational Interviewing-based Telehealth Intervention for Bacterial Sexually Transmitted Infection Screening: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Zenyth: Motivational Interviewing-based Telehealth Intervention for Bacterial Sexually Transmitted Infection Screening (NCT06100250), a na na study. The primary outcome is Number of Participants That Schedule a Pre-test Session.

2. Clinical Question

The study focuses on feasibility and acceptability: whether participants are willing to collect and return specimens for bacterial STI testing with live audio/video support. This is a question about participation in a screening process, not a randomized comparison of treatments. The registry describes gonorrhea, chlamydia, and syphilis among the bacterial STIs of interest. It also lists secondary outcomes involving STI-related knowledge, the likelihood of annual testing, self-efficacy for specimen self-collection, test results, and initiation of treatment after a positive result. The registry record does not report the numerical primary outcome result, so the number who scheduled a session cannot be assessed from the recorded information.

3. Trial Design

The study is listed as completed, with an enrollment of 75. The registry record gives a start date of 2024-04-19 and a primary completion date of 2025-03-07. The sponsor is the University of Michigan. The intervention is described as motivational interviewing and specimen self-collection, delivered through a telehealth intervention for bacterial STI screening.

The design is single-group, with allocation listed as NA and masking listed as none. There is no separate control arm against which to compare the intervention. Consequently, the central design question is whether participants in this group schedule the pre-test session, rather than whether outcomes differ between randomized groups. The registry record describes the primary analysis population as all 75 participants invited to schedule a pre-test session after completing the baseline survey.

The registry record lists 16 outcome measures and 2 analyses. It names secondary outcomes concerning knowledge, annual testing likelihood, self-efficacy, bacterial STI test results, and treatment initiation after a positive result. The specific results and analysis details for those outcomes are not reported in the registry record. The listed phase is NA. The registry record does not describe a sample-size justification for the study’s design, nor does it report further details about recruitment, intervention delivery, or follow-up beyond the primary endpoint’s stated timeframe.

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: Analysis population includes all 75 participants who were invited to schedule a pre-test session after completing the baseline survey

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 That Schedule a Pre-test Session, measured over Up to 8 weeks after participants complete the baseline survey.

The primary endpoint is the number of participants who schedule a pre-test session. The registry defines the relevant period as up to 8 weeks after participants complete the baseline survey. Its unit is participants, and the analysis population is described as all 75 participants invited to schedule a session after that survey.

This count addresses a practical feasibility question: whether participants proceed to arranging a pre-test session as part of a telehealth-supported bacterial STI screening process. A count of scheduled sessions can describe participation in that step. It does not, by itself, establish whether specimens were returned, whether testing was completed, or whether the intervention changed behavior compared with another approach. Those are distinct outcomes.

The registry record does not report the number who scheduled a session. It also does not give a numerical estimate, uncertainty interval, or other result for this endpoint. Therefore, the endpoint’s definition and timeframe can be described, but its observed value and precision cannot be assessed from the registry record. The scheduled-session measure should also be distinguished from secondary outcomes about test results and treatment initiation, which are separately listed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is a participant count: the number who schedule a pre-test session during the stated period. Counts describe how many observed events occurred in a defined group. Their interpretation depends on a clear event definition, a population at risk of experiencing the event, and a timeframe. The registry specifies the event, the analysis population, and a period of up to 8 weeks after baseline survey completion. It does not report the observed count.

What does a count tell the reader?

A count is directly interpretable as the number of participants with the event, but its size depends on how many participants were included. General statistical explanation: a proportion or rate can sometimes help compare groups of different sizes, but such a quantity requires an appropriate denominator and a clearly specified observation period. No such calculated value should be inferred from the enrollment alone. The registry identifies 75 participants as the primary analysis population, but does not state how many scheduled or provide an endpoint estimate.

Counts can also be affected by whether every participant’s status is known. If some participants have no recorded scheduling outcome, they cannot automatically be treated as having no event. The registry record does not report the amount or handling of missing primary outcome data, so the extent to which all invited participants had an ascertainable outcome is not clear from the recorded details.

How does the single-group design affect interpretation?

The registry describes a single-group study, with no allocation to a distinct comparison arm. A count or proportion in that group can describe what happened among the participants observed, but it does not supply a direct contrast with an alternative. General statistical explanation: a randomized comparison can help separate intervention-related differences from other differences between groups, while a single-group description cannot make that same contrast. This limitation applies even when an endpoint is measured consistently.

The study’s stated purpose concerns willingness to collect and return specimens with live audio/video support. The primary endpoint captures an earlier step, scheduling a pre-test session. It is therefore important to keep the primary measure separate from specimen return, completion of testing, positive or negative test findings, and treatment initiation. These are listed as distinct outcome topics, and numerical results for them are not reported in the registry record.

What analysis details are documented?

The registry identifies the outcome as a count of participants and lists 16 outcome measures and 2 analyses. It does not report the statistical model used for the primary endpoint, the form of any uncertainty interval, the handling of missing outcomes, or a planned threshold for interpreting the count. A model or significance test should not be assumed from the fact that outcomes and analyses are listed.

General statistical explanation: when count data are analyzed, the method should reflect the structure of the observations and the question being asked. A simple count may be sufficient for a descriptive feasibility question; a model may be used when there are additional features to account for. Over-dispersion matters in some count models: it means that observed variation is greater than the model’s assumed variation, which can make standard errors and uncertainty estimates unreliable if ignored. The registry record does not say that an over-dispersion assessment or count model was used in this study.

How should planning illustrations be read?

The planning assumptions associated with the sample-size illustrations specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. Those are described as planning illustrations based on the observed effect, not as the trial’s own design justification. The registry record itself describes a single-group study, so the two-arm allocation assumption is not a description of the actual study design. The planning illustrations are not observed power and do not show the probability that this completed study detected an effect.

General statistical explanation: sample-size planning asks how much information a proposed design may need under specified assumptions. Results depend on the effect size, variability, outcome type, analysis, and decision threshold assumed. Illustrations based on a fraction of an observed effect show hypothetical planning scenarios; they do not replace a documented prospective justification. The registry record does not report the study’s own sample-size rationale or the assumed effect used when the study was designed.

For time-to-event outcomes, the planning description identifies total events as the quantity used in its illustrations; for other outcomes, it identifies participants per arm. The primary endpoint is a participant count, and the actual study has no comparison arms. Any planning values tied to a two-arm setup therefore need to be understood as hypothetical illustrations, not as a report of the design or findings of this single-group trial.

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("Telehealth Intervention")
n      <- c(75)
events <- c(74)
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  Telehealth Intervention  75  74  98.7  92.8  100.0  92.8  99.8  92.9  99.7

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 16 outcome measures and 2 analyses. It names secondary outcomes related to STI knowledge, likelihood of annual bacterial STI testing, self-efficacy for specimen self-collection, test results for gonorrhea, chlamydia, and syphilis, and initiation of treatment within 1 week of a positive result. The record does not report how the 2 analyses map to the outcome measures, which outcomes were included in each analysis, or whether any outcomes were prioritized beyond the stated primary endpoint.

When several outcomes are examined, the chance of finding at least one apparently notable result can increase if each is tested separately. General statistical explanation: multiplicity procedures can control that risk, but the appropriate approach depends on the analysis goals and the relationships among outcomes. The registry record does not report whether multiplicity was addressed, whether hypothesis tests were planned, or whether outcomes were intended to be interpreted descriptively.

The primary analysis population is described as all 75 participants invited to schedule a pre-test session after completing the baseline survey. The registry record does not explain how missing or unknown scheduling outcomes were handled. It also does not report missing-data methods for the secondary outcomes, the analysis populations used for them, or whether those populations differed from the primary population. The absence of those details limits assessment of how complete the outcome data were and which participants contributed to each result.

The record does not report an analysis plan specifying imputation, sensitivity analyses, or rules for excluding observations. These methods should not be presumed. The listed sample-size illustrations are planning scenarios and do not resolve questions about missing outcomes or multiplicity in the completed study.

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 75 participants at risk for the serious adverse event category and records 0 serious adverse events. It also lists 75 at risk for other adverse events and records 0 other adverse events. The death count is 0. No serious adverse event terms are listed.

These are the recorded safety figures for the telehealth intervention group. A zero count means no events of that category are recorded in the registry results; it is not proof that an event is impossible or that there is no safety concern in other settings or populations. General statistical explanation: when no events are observed in a study group, the underlying event frequency remains uncertain, especially when the number of participants and duration of observation are limited. The registry record does not provide additional detail about safety ascertainment methods or the period covered by these figures.

The figures should also be read separately from the primary feasibility endpoint. They do not indicate how many participants scheduled sessions, returned specimens, or completed testing. The listed count of 0 deaths is a distinct safety result, not a substitute for the adverse-event counts.

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

The registry record establishes that this was a completed, single-group study with an enrollment of 75 and a telehealth intervention based on motivational interviewing and specimen self-collection. Its primary endpoint asks how many participants scheduled a pre-test session within up to 8 weeks after completing the baseline survey. The record describes the primary analysis population as all 75 participants invited to schedule, but does not report the number who did so.

Accordingly, the available information supports an explanation of what the investigators set out to measure, but not a conclusion about the observed level of scheduling. It does not establish that participants were willing or unwilling to proceed, because the endpoint result is not reported in the registry record. Nor can an enrollment count stand in for the number who experienced the primary endpoint.

The design does not include a separate comparison group. Any observed event count, if reported, would describe participants in the intervention group; by itself it would not show that the intervention caused a change or that it performed differently from another approach. A single-group feasibility study can address whether a study process was undertaken and can provide descriptive information, but it does not furnish a randomized treatment contrast.

The secondary outcomes include knowledge, annual testing likelihood, confidence in specimen self-collection, test results, and treatment initiation after a positive result. Their inclusion in the registry does not establish what those outcomes showed. Numerical results for them are not reported in the registry record. Likewise, the recorded zero counts for serious and other adverse events and for deaths describe the safety entries, but do not provide the missing primary endpoint result.

General statistical explanation: estimates are more informative when accompanied by measures of uncertainty and clear definitions of the population and analysis. The registry record gives the primary endpoint definition and analysis population, but no numerical endpoint estimate or uncertainty interval. The proper interpretation is therefore limited to the study structure and recorded safety counts; claims about the rate of scheduling, test uptake, clinical outcomes, or comparative effectiveness are not supported by these details.

14. Why This Trial Matters Statistically

This study raises a statistical question that is distinct from whether an intervention changes a clinical outcome: can a telehealth-supported process engage participants in a specific screening step? Feasibility measures such as scheduling can help characterize where people do or do not proceed through a study process. They are meaningful only when the event, timeframe, and population are defined clearly, as they are for the stated primary endpoint.

The endpoint also illustrates why an outcome’s place in the care or research pathway matters. Scheduling a pre-test session is not the same as returning specimens, completing testing, receiving a result, or initiating treatment. The registry lists these as separate topics or outcomes. Keeping them distinct avoids treating an early process measure as evidence about later steps.

Statistically, the single-group design determines the scope of any conclusion. A descriptive count can characterize the enrolled group, but without a comparator it cannot estimate a difference attributable to the intervention. This distinction is important in feasibility research, where estimates of participation may be useful for understanding study procedures but do not answer the same question as a controlled efficacy comparison.

The registry record also shows why outcome reporting is essential. The primary endpoint is defined and its analysis population is identified, yet the numerical scheduling result is not reported. Without that value, readers cannot assess the observed participation level or its precision. A clearly stated endpoint is valuable, but it cannot replace the result itself.

Finally, planning illustrations should be separated from evidence about the completed study. The described assumptions use equal allocation between two arms, whereas the registered design is single-group. Recognizing that distinction prevents hypothetical sample-size scenarios from being mistaken for the actual study design, a prospective sample-size justification, or observed statistical power.

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 most direct limitation for interpreting this trial is that the registry record does not report the primary endpoint count. The endpoint’s definition and analysis population are stated, but there is no numerical result for the number of participants who scheduled a pre-test session. This prevents assessment of the study’s central feasibility outcome from the registry record.

The single-group design has no separate comparator. It can describe the experience of participants receiving the telehealth intervention, but it cannot provide a like-for-like estimate of how scheduling or other outcomes would have differed under another approach. Allocation is listed as NA and masking as none.

The primary outcome is an early process measure. Scheduling a pre-test session does not establish specimen return, completed screening, test result, or follow-through after a positive result. Although the registry lists secondary outcomes covering some of these topics, their numerical findings are not reported in the registry record.

Further information about missing outcomes is not reported in the registry record. The analysis population is defined as all 75 invited participants, but the record does not state whether every participant’s scheduling status was known or how any unavailable outcomes were handled. The statistical model, uncertainty estimates, and analysis procedures are also not reported.

The sample-size illustrations use assumptions for a two-arm design, while the registered study is single-group. They should not be interpreted as the study’s design justification or as evidence about power in the completed trial. The registry record does not report its own sample-size rationale. Together, the absent endpoint result, lack of a comparator, and limited analysis detail constrain what can be concluded from the recorded information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Zenyth: Motivational Interviewing-based Telehealth Intervention for Bacterial Sexually Transmitted Infection Screening — NCT06100250.
• Registry record last updated 2025-07-01; status last verified 2025-06.
• Results first posted 2025-07-01.
• 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

NCT06100250 is a completed, single-group study sponsored by the University of Michigan. It enrolled 75 participants and evaluated a motivational interviewing-based telehealth intervention for bacterial STI screening, including specimen self-collection support. The registry record describes the population as gay and bisexual men living with HIV.

The primary endpoint is the number of participants scheduling a pre-test session within up to 8 weeks after completing the baseline survey. The primary analysis population is described as all 75 participants invited to schedule. The numerical result for this endpoint is not reported in the registry record. The record lists secondary outcomes concerning knowledge, testing likelihood, self-efficacy, test results, and treatment initiation, but does not report numerical findings for them.

The safety entries record 0 serious adverse events, 0 other adverse events, and 0 deaths. No serious adverse event terms are listed. The single-group design has no separate comparator, and the registry record does not report the study’s own sample-size justification or detailed methods for missing data and statistical analysis.