Supporting Tailored And Responsive PrEP in Rural North Carolina: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Supporting Tailored And Responsive PrEP in Rural North Carolina (NCT05984030), a randomized na study. The primary outcome is Proportion of Participants Reporting PrEP Initiation by 3 Months.

2. Clinical Question

3. Trial Design

The registry describes a randomized, open-label, parallel-group trial, with the STARR NC Intervention Condition compared with the STARR NC Standard-of-Care Control Condition. Randomization means assignment was intended to occur by chance, but the method used to generate or implement the allocation sequence is not reported in the registry record. Masking is listed as none. The record does not explain whether outcome verification or any other study procedures were conducted by personnel unaware of assignment.

The study is listed as completed, with enrollment of 17. Its start date is 2023-08-31 and its primary completion date is 2025-05-02. The phase is listed as NA. The brief description places the randomized trial within a broader two-phase project and identifies the primary outcome as PrEP uptake within 3 months of an index STI clinic visit. The record does not provide further detail about the transition between project phases or which activities fall within the posted trial results.

The arm descriptions distinguish a multilevel intervention from the clinic’s standard PrEP referral services, with a control-version digital platform also used in the control arm. The primary outcome arm entries list n=6 for the intervention and n=10 for standard of care. The registry record does not explain how these arm-specific counts relate to the enrollment figure or identify the analysis population used for the outcome. It also does not report a target enrollment, recruitment flow, site-level enrollment, or reasons participants may have been excluded from the posted outcome.

The registry lists 22 outcome measures, including the primary initiation outcome and secondary measures of later initiation, adherence, duration of PrEP use, and use-related measures for different PrEP strategies. The record marks the study completed, but that status alone does not supply details about follow-up completion or the conduct of each outcome assessment.

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: Prospective participants deemed study-eligible are required to complete the following before being randomized and enrolled in the study: (1) informational video, (2) informed consent, (3) HIPAA authorization, (4) baseline survey. To continue study participation, participants must receive baseline HIV testing and be confirmed seronegative within 45 days of completing the pre-screening questionnaire. Participants who do not verify HIV-negative status within that 45-day window are study-stopped.

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 Proportion of Participants Reporting PrEP Initiation by 3 Months, measured over 3 months.

The primary endpoint is the proportion of participants reporting PrEP initiation by 3 months. The registry defines initiation as verified self-reported use of pre-exposure prophylaxis, with a first dose of oral or injectable PrEP at or before the 3-month point. Within each arm, the numerator is the number verified to have started PrEP and the denominator is the total number of participants in that arm.

This endpoint focuses on uptake after contact with an STI clinic, rather than on PrEP use alone at a single later time. It is relevant to the multilevel strategy because the intervention components are designed to support linkage to PrEP services, including navigation and telehealth referral. The outcome therefore records whether initiation was reported within the stated timeframe; it does not by itself describe the timing of initiation within that period, persistence after starting, or adherence to a chosen PrEP strategy.

The registry also lists secondary outcomes concerning initiation by 6 months, adherence and consecutive months of use over follow-up periods, and measures specific to daily oral, event-driven oral, and injectable PrEP. Those measures address aspects of use beyond the primary uptake outcome. The posted primary results are proportions for the two arms, but no confidence interval or comparative estimate is reported in the registry record. The endpoint should therefore be read as a descriptive measure of reported uptake, not as a complete account of PrEP persistence or as an adjusted estimate of the intervention’s effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods relevant to interpreting the primary results begin with the outcome’s scale. A binary outcome classifies each participant as meeting or not meeting a defined event criterion. Here, the event is verified self-reported PrEP initiation by 3 months. An arm-specific proportion represents the share of participants in that arm classified as having the event, using the arm total as the denominator. The posted values are 0.33 for the intervention arm and 0.1 for the standard-of-care arm. The registry record does not post the event counts or a comparative model for this outcome.

What does randomization contribute?

In general, randomization assigns participants to study groups by chance and is intended to make the groups comparable, on average, before the intervention is delivered. That supports interpreting an arm-to-arm contrast as a comparison of assigned strategies, provided the design and analysis are carried out appropriately. Randomization does not guarantee that small groups will have similar characteristics, and it does not by itself address missing outcomes, deviations from assigned care, or measurement problems. The record identifies the allocation as randomized, but the sequence generation, concealment procedures, and analysis approach are not reported in the registry record.

The trial is listed as open-label, so participants and study personnel are not described as masked to assignment. Lack of masking can matter for outcomes based on self-report because awareness of group assignment may influence reporting or assessment. The primary outcome is described as verified self-reported use, but the record does not describe the verification procedure, who performed it, or whether outcome assessors were masked. It is therefore not possible to assess from the registry record how these features may have affected outcome classification.

Why are uncertainty estimates important?

A point estimate is a single summary of the observed data. A confidence interval, in general, adds information about statistical uncertainty under a specified method and its assumptions. It does not describe every source of uncertainty, such as errors in measurement or departures from the planned design, but it can show whether the estimate is precise or imprecise. No confidence interval for the primary arm values or their contrast is reported in the registry record. No p-value or other inferential result for the primary comparison is reported either. As a result, the numerical values should not be interpreted as evidence that a threshold for statistical significance was reached.

For a binary endpoint, a comparison might be expressed as a difference in proportions, a relative measure, or a model-based effect estimate. Each requires a stated method and an uncertainty measure to support inferential interpretation. No such comparative statistic is posted for the primary outcome. No new contrast should be inferred from the arm values alone, because doing so would require an analysis choice and would not substitute for a sponsor-reported analysis. The registry record does not report a statistical analysis plan specifying a preferred effect measure or model.

What do the planning illustrations represent?

The planning illustrations use the observed effect as a basis and describe a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. Their stated purpose is to consider effects set at a fraction of the observed effect. Such calculations are planning illustrations rather than evidence about the probability that the completed trial detected an effect. They are not observed power and should not be read as a retrospective measure of how conclusive the results are. The record does not identify these illustrations as the trial’s original design calculation, and the assumptions are explicitly distinguished from the trial’s own design.

Planning estimates depend on assumptions about the effect to detect, allocation, the analysis, and the chosen error criterion. If an observed effect is used as the reference, the resulting illustration inherits uncertainty from that observed estimate. With a small set of outcome observations, the observed effect may itself be imprecise. The registry record does not report a sample-size justification from the protocol, a target effect specified before enrollment, or a planned power calculation for this trial. Therefore, the planning illustrations cannot establish whether the original study was adequately sized for its intended question.

How should the additional outcomes be considered?

The registry lists 22 outcome measures and identifies 21 secondary outcomes as posted. These include initiation by 6 months, adherence among PrEP initiators, consecutive months of use, and measures related to daily oral, event-driven oral, or injectable PrEP. The outcome definitions vary in both population and time window: some concern all participants, while others concern participants who initiate a specific strategy. Those outcomes address distinct questions and should not be treated as interchangeable with the primary 3-month initiation endpoint. Their estimates and analysis details are not reported in the registry record in the information available for this interpretation.

The record lists zero analyses. It does not describe a statistical model, covariate adjustment, interim monitoring, multiplicity procedure, missing-data method, or analysis population. These omissions limit the ability to determine how the posted results were generated or how they relate to any prespecified plan. General statistical principles can explain why these details matter, but they cannot fill in methods that are not reported in the registry record.

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("STARR NC Intervention Condition", "STARR NC Standard-of-Care Control Condition")
n      <- c(6, 10)
events <- c(0, 0)
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  STARR NC Intervention Condition  6  0  0.0  0.0  45.9  0.0  39.0  0.4  41.0
ARM  STARR NC Standard-of-Care Control Condition  10  0  0.0  0.0  30.8  0.0  27.8  0.2  28.5

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 22 outcome measures, including the primary outcome and 21 secondary outcomes, but does not report a multiplicity strategy. When a study evaluates multiple outcomes or multiple comparisons, the chance of at least one apparently notable result can increase if each is assessed independently. In general, multiplicity procedures may control that risk or prioritize a smaller set of planned tests. No such procedure, hierarchy, or distinction between confirmatory and exploratory outcomes is reported in the registry record. Since no analyses are listed, the record also does not provide a set of test results from which to assess how multiplicity was handled.

Missing data are another important concern for a proportion endpoint. If a participant’s PrEP initiation status is unknown, the result can depend on whether that participant is included, excluded, or classified using an imputation approach. The registry record does not report the number of missing primary outcomes, reasons for missingness, follow-up completion, or any method used to address missing data. It also does not state whether all randomized participants were included in the primary analysis or whether a different population was used.

The record lists enrollment of 17, while the primary outcome arm entries list n=6 and n=10. It does not explain the relationship between these figures or provide participant-flow information that would clarify the outcome denominators. The record also does not report whether participants were analyzed according to their randomized assignment, whether any participants were excluded after randomization, or whether protocol deviations occurred. Without these details, the analysis population and the potential influence of missing outcomes cannot be assessed from the registry record. The posted arm values should therefore be interpreted as reported summaries, not as a fully documented intention-to-treat analysis.

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 adverse-event entries report serious adverse events affecting 0 participants in the intervention group and 0 in the standard-of-care control group. The serious-event at-risk counts are 7 and 10, respectively. The entries also report other adverse events affecting 0 participants in each group, with at-risk counts of 7 and 10. Deaths are reported as 0 in both groups.

These figures describe what is recorded for the listed groups and do not demonstrate that no adverse events could occur. The registry record does not provide additional detail on the period during which events were collected, how events were solicited or classified, or the completeness of safety follow-up. It lists no top serious-event terms. The at-risk counts for adverse-event reporting are not the same as the primary outcome arm counts, and the record does not explain the relationship among these counts. Safety data should therefore be read as the posted event summary, with the limitations of the recorded follow-up and definitions in mind.

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

The primary result gives a descriptive comparison of reported PrEP initiation by 3 months in a randomized, parallel-group study. The posted values are 0.33 in the multilevel intervention arm and 0.1 in the standard-of-care arm. They indicate the arm-specific proportions recorded for the defined endpoint. The registry record does not provide an uncertainty interval, a direct comparison estimate, or a test result, so the precision and statistical compatibility of the observed contrast cannot be judged from these values alone.

The result does not isolate the contribution of any single intervention component. The intervention combines navigation, a digital health platform, and telehealth referral, while the control includes standard clinic referral and a control version of the digital platform. A two-arm comparison of these packages cannot establish which component may account for an observed pattern. Details about how consistently the components were delivered are not reported in the registry record.

The endpoint concerns initiation by a specified time. It does not establish sustained PrEP use, adherence, or protection over later periods. Although the registry lists secondary outcomes addressing some of these topics, their numerical results and analysis methods are not reported in the registry record. The primary result also does not establish how the strategy would perform in other settings, since the study description focuses on rural and peri-urban North Carolina STI clinic settings and the record does not report broader recruitment details.

Randomized design is relevant to comparative interpretation, but it cannot replace information about participant flow, missing outcomes, baseline characteristics, outcome verification, and the prespecified analysis. Those details are not reported in the registry record. The results therefore support a limited statement about the posted arm-specific endpoint values, not a conclusion about clinical benefit, certainty of an effect, or the comparative performance of the intervention beyond this study’s recorded data.

14. Why This Trial Matters Statistically

This trial raises statistical questions common to behavioral and service-delivery interventions. Its intervention is multilevel, combining individual navigation, digital support, and referral to telehealth services. The outcome is not a laboratory measurement but a time-bounded report of PrEP initiation, described as verified self-report. Interpreting such an endpoint depends on both the definition of initiation and the process used to verify it. The registry record supplies the definition but not enough detail to assess the verification process.

The randomized parallel-group design provides a framework for comparing the intervention package with standard-of-care services. However, the posted primary arm counts are limited, and no comparative uncertainty estimate is reported. General statistical reasoning emphasizes that point estimates from small samples can be unstable: they can change materially with a small number of different outcome classifications. That does not invalidate the observations, but it does make precision especially important when drawing comparative conclusions.

The record also illustrates the importance of distinguishing the study’s own design from retrospective planning illustrations. The posted illustrations use observed effect assumptions and specified planning conventions; they do not report observed power or confirm that the trial was originally designed for those assumptions. Separately, the registry record does not report a protocol-based sample-size justification or an analysis plan. Those details matter because they clarify what effects the study aimed to estimate, which outcomes were prioritized, and how uncertainty and multiple outcomes were to be handled.

Finally, uptake is only one part of PrEP use. The registry includes secondary questions about adherence and persistence, but the primary endpoint cannot answer them. Clear reporting of outcome definitions, denominators, missingness, and comparative estimates would be essential to connect an uptake result with the broader pattern of use.

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.

Several trial-specific details needed for a fuller interpretation are not reported in the registry record. These include eligibility criteria, baseline characteristics, recruitment and participant flow, site-specific enrollment, and the relationship between the enrollment figure of 17 and the arm-specific primary outcome counts of n=6 and n=10. Without participant-flow information, it is difficult to determine how the primary outcome denominator was formed or whether outcome data were available for all randomized participants.

The record identifies a randomized design but does not describe the random sequence method, allocation concealment, or the analysis population. Masking is listed as none, and the outcome relies on verified self-report; further details about verification and assessor masking are not reported. The intervention combines multiple components, but the record does not report component uptake, fidelity, or exposure. The standard-of-care services may be tied to the recruiting clinic, yet clinic-level variation is not described.

For the primary outcome, arm-specific values are posted without a confidence interval or a direct comparative analysis. The record does not provide missing-outcome counts, a missing-data method, baseline-adjusted estimates, or a prespecified statistical analysis plan. It also does not report a multiplicity approach for the many outcome measures. Secondary outcome definitions are listed, but their results are not reported in the registry record. These gaps limit assessment of precision, robustness, and the relation of the posted endpoint to other measures of PrEP use.

The listed planning assumptions are illustrations based on the observed effect, rather than a report of the original design rationale. A protocol-based target sample size, design effect, or interim-analysis plan is not reported in the registry record. These limitations call for cautious, descriptive interpretation and do not permit a definitive assessment of the intervention’s comparative effect.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Supporting Tailored And Responsive PrEP in Rural North Carolina — NCT05984030.
• Registry record last updated 2025-08-15; status last verified 2025-06.
• Results first posted 2025-08-15.
• 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

The registry record describes NCT05984030, “Supporting Tailored And Responsive PrEP in Rural North Carolina,” with the official title “Meet me Where I am: A Multilevel Strategy to Increase PrEP Uptake and Persistence in Rural NC.” It is listed as a completed randomized, open-label, parallel-group study with enrollment of 17 and phase NA. The listed start date is 2023-08-31 and the primary completion date is 2025-05-02.

The primary endpoint is verified self-reported initiation of oral or injectable PrEP by 3 months. Posted arm values are 0.33 for the intervention group, n=6, and 0.1 for standard of care, n=10. No comparative estimate, confidence interval, or hypothesis-test result is reported in the registry record. Serious adverse events, other adverse events, and deaths are each recorded as 0 in both groups. Analysis methods, missing-data handling, and the relationship between enrollment and outcome counts are not reported in the registry record.