Life-Steps Counseling to Enhance Adherence and Engagement in PrEP Care: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Life-Steps Counseling to Enhance Adherence and Engagement in PrEP Care (NCT04316715), a randomized na study. The primary outcome is Participants With TFV-DP Concentrations Consistent With Adherence (≥4 Doses/Week).

2. Clinical Question

3. Trial Design

This is a randomized, parallel-group trial of behavioral approaches intended to affect PrEP medication-taking and engagement in care. The registry record lists the study as completed, with an enrollment of 300. It lists the study start as 2020-09-03 and primary completion as 2025-07-08. Phase is recorded as not applicable.

The intervention arm is described as receiving standard of care and daily text message reminders. Participants in that group who demonstrate continued adherence challenges are also described as receiving 4-6 weekly sessions of Lifesteps for PrEP. The comparison arm receives standard of care without an intervention outside that care. Masking is listed as none, so the record does not describe a masked trial.

The primary endpoint concerns adherence measured using TFV-DP concentrations from dried blood spot testing. Counts are reported at 3, 6, 9, 12, 15, and 18 months, among participants with an analyzable sample at the relevant time point. Retention in PrEP care is listed as a secondary outcome. The registry record lists three outcome measures and three analyses, but the details of the additional measures and analyses are not reported in the registry record.

The registry record does not report the randomization procedure, allocation concealment, the exact timing or delivery procedures for the text messages, or the criteria used to identify continued adherence challenges. It also does not report a detailed statistical analysis plan or a sample-size justification. The trial design can therefore be described from the listed group assignments and endpoint, but further operational or analytic details should not be inferred.

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.

3-Month Follow Up

Reasons for not completing this period:

6-Month Follow Up

Reasons for not completing this period:

9-Month Follow Up

Reasons for not completing this period:

12-Month Follow Up

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: At each time-point, participants who had an analyzable dried blood spot (DBS) sample are included.

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 Participants With TFV-DP Concentrations Consistent With Adherence (≥4 Doses/Week), measured over 3, 6, 9, 12, 15, and 18 months.

The primary endpoint counts participants whose TFV-DP concentrations in dried blood spots are consistent with medication adherence. The registry record defines the adherence level as 4+ pills per week and describes the outcome as categorical: adherent or not adherent. TFV-DP is measured using dried blood spot testing, so the endpoint uses a biological measurement rather than relying only on a participant’s report of medication-taking.

The count is reported at 3, 6, 9, 12, 15, and 18 months. At each time point, the endpoint population includes participants with an analyzable DBS sample at that time. Thus the number contributing information may depend on sample availability at each assessment; the registry record does not state that the same participants contribute at every time point.

Repeated assessments can describe adherence status over follow-up rather than at a single visit. However, a count at one time point does not by itself describe an individual participant’s pattern across visits. The registry record does not report a single summary measure combining these time points, and the primary outcome has not been reduced to one comparison. It also does not provide the observed counts or a comparison estimate, so the magnitude and precision of any group difference are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial is listed as randomized and parallel-group. In general, randomization aims to make assigned groups comparable, on average, with respect to measured and unmeasured participant characteristics. It does not guarantee identical groups in any particular trial. The registry record does not describe the randomization sequence, allocation concealment, or any procedures used to implement assignment, so those details are not reported in the registry record.

What does the primary outcome count?

The primary endpoint is a count of participants whose DBS TFV-DP concentration meets the record’s adherence definition, which is 4+ pills per week. Each participant’s result is categorized as adherent or not adherent at a given assessment. The count is not the same as a continuous measure of drug concentration: it records how many participants meet a specified category, rather than how far each concentration lies above or below a threshold.

In general, a binary endpoint can be summarized using counts and denominators, and comparisons can be expressed in several ways. The choice of a comparison measure depends on the analysis plan and the scientific question. The registry record does not report a single comparison for this primary outcome, and the outcome spans multiple time points. It would therefore be inappropriate to treat any one unreported contrast as the trial’s definitive result.

How should repeated time points be understood?

Measurements are scheduled at 3, 6, 9, 12, 15, and 18 months. These are repeated assessments, potentially involving the same participants at different visits. In general, observations from one participant across time may be related; analyses that account for that dependence can differ from analyses that treat every visit as independent. The registry record does not state whether the primary analysis accounts for repeated measurements, compares groups separately at each visit, or uses another approach.

The endpoint population at each time point includes participants with an analyzable DBS sample. In general, an assessment that is unavailable or not analyzable cannot contribute a measured adherence classification at that visit. The reasons for missing or unanalyzable samples, their frequency, and any methods for handling them are not reported in the registry record. Without those details, it is not possible to determine whether missing outcome information could affect interpretation.

What do confidence intervals and p-values convey?

In general, a confidence interval describes the precision of an estimated effect and the range of values compatible with the data under the method used. A wider interval indicates less precision than a narrower interval, while an interval’s relation to a null value can be relevant for interpreting a comparison. A p-value measures how incompatible the observed data are with a specified null model, under the assumptions of the analysis. Neither quantity alone expresses clinical importance or resolves concerns about measurement, missing data, or analysis choices.

No effect estimate, confidence interval, or p-value for the primary outcome is reported in the registry record. Therefore, its statistical precision and evidence against a null comparison are not reported in the registry record. No recalculated estimate is presented because the relevant primary-outcome counts and denominators are not reported.

What analysis choices remain unclear?

The registry record lists three analyses but does not describe their methods or map them to the outcomes. The statistical model, covariate adjustment, handling of repeated observations, treatment of missing data, and analysis population are not reported in the registry record. It also does not report a prespecified primary contrast or a detailed plan for interpreting results across the multiple assessments.

In general, over-dispersion matters when observed variation in count data is greater than expected under a model’s assumptions; using a model that does not accommodate that variation can produce misleading uncertainty estimates. That concept is not an indication that over-dispersion occurred in this trial. The primary endpoint is described as a count of participants meeting a binary criterion, and the registry record does not report an over-dispersion assessment or model.

Any planning illustration based on an observed effect should be distinguished from the trial’s original design justification. The registry record does not report its sample-size justification, assumptions for such a justification, or interim analyses. Planning calculations are not observed power and do not replace the estimated effect and its precision.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is assessed at 3, 6, 9, 12, 15, and 18 months. Looking at several time points raises a general multiplicity issue: the more comparisons considered, the greater the chance that some result may appear noteworthy by chance if no adjustment or prespecified interpretation strategy is used. The registry record does not report whether a multiplicity adjustment was planned, which time point was designated as the principal contrast, or how results across visits were to be interpreted.

The record lists three outcome measures and three analyses, but the analysis details and the relationship between analyses and outcomes are not reported in the registry record. Retention in PrEP care is listed as a secondary outcome. The record does not describe its definition, timing, or analysis. Without an analysis plan, it is not possible to determine whether the assessments were treated as separate questions or combined in a model.

For the primary endpoint, each time-point population includes participants with an analyzable DBS sample. In general, missing or unusable outcome data can affect interpretation, especially if the availability of measurements differs between groups or is related to adherence. The registry record does not report the number or reasons for missing samples, how missing outcomes were handled, or whether sensitivity analyses were conducted.

The analysis population is also not reported in the registry record. It is not stated whether analyses followed randomized assignment, were limited to participants with available measurements, or used another definition. No interim analyses or stopping rules are reported. These omissions limit assessment of how the results, if available, were selected and how robust they would be to missingness and multiple comparisons.

11. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: gallbladder (0.7%), food poisoning (0.7%), covid (0.7%), gallstones/baker act (0.7%), outpatient surgery (0.7%).

The registry record reports serious adverse event counts by group. In the Life-Steps for PreP group, 1 of 151 participants at risk is listed with a serious adverse event; in the Standard of Care group, 5 of 149 participants at risk are listed. For the other adverse-event count, the record lists 1 of 151 in the Life-Steps for PreP group and 1 of 149 in the Standard of Care group. Deaths are listed as 0 in both groups.

These counts describe what the registry record reports; they do not establish that an intervention caused or prevented an event. The record does not provide event-level timing, a detailed attribution assessment, or an analysis comparing safety between groups. The listed top serious-event terms are Gallbladder, Food poisoning, COVID, Gallstones/Baker Act, Outpatient Surgery, and Assault, each reported as 0.7%. Those terms and percentages should be read as registry listings, not as a complete account of all clinical context.

In general, safety counts are easier to interpret when their definitions, observation periods, and participant denominators are clear. The figures should not be combined or converted into additional rates without the relevant analytic details. The registry record does not report those details, so the counts are descriptive rather than a standalone comparative safety analysis.

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

The registry record describes a randomized comparison of standard of care plus daily text reminders, with Lifesteps for PrEP sessions for a subset with continued adherence challenges, against standard of care alone. Its primary endpoint uses dried blood spot TFV-DP concentrations to classify adherence at several follow-up time points. This establishes what the trial was designed to measure, but it does not provide the observed primary-outcome counts or a group comparison.

The record lists the study as completed and reports enrollment of 300. Completion and enrollment do not reveal whether adherence differed between groups, how large any difference was, or how precisely it was estimated. No primary outcome effect estimate, confidence interval, or p-value is reported in the registry record. It is therefore not possible to draw a comparative conclusion about the primary endpoint from these registry entries.

The outcome is a threshold-based classification at an assessment. In general, such a measure can be useful for describing the proportion of participants meeting a defined criterion, but it does not show the full distribution of drug concentrations or the day-to-day pattern of taking medication. Nor does an isolated visit classification describe adherence across all follow-up visits. The registry record does not report a combined longitudinal result.

The intervention is not counseling alone for every participant: the described intervention group receives daily text reminders, and a subset with continued challenges is also to receive counseling sessions. The registry record does not report results separated by receipt of counseling, so the effects of the components cannot be disentangled from these details. Retention is listed as a secondary outcome, but no retention result is reported.

The serious adverse event counts are descriptive and do not provide a causal safety comparison. Taken together, the registry information clarifies the study question, assignment structure, endpoint definition, and some safety counts. It does not establish the direction or magnitude of the primary outcome, the precision of any effect, or the comparative result for retention.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question about measuring medication adherence repeatedly rather than relying on a single assessment. The primary outcome uses TFV-DP concentrations from dried blood spots and classifies participants according to a stated adherence threshold. Considering measurements at 3, 6, 9, 12, 15, and 18 months makes it important to distinguish a visit-specific count from a summary of adherence over time.

The endpoint also makes the analysis population consequential. At each time point, only participants with an analyzable DBS sample are included. In general, the completeness and pattern of repeated measurements can affect both precision and interpretation. Understanding those features requires counts of available samples and an explicit missing-data approach, which are not reported in the registry record.

The intervention structure illustrates another important issue: an assigned strategy can contain more than one component. The intervention group receives daily text reminders, while a subset with continued adherence challenges may also receive Lifesteps for PrEP sessions. A comparison between assigned groups would address the strategy as described; it would not, on its own, isolate the contribution of counseling from reminders. The registry record does not report component-specific results.

Finally, multiple assessment times and listed analyses make prespecified analysis choices important. In general, identifying the principal comparison and explaining how repeated measures, missing data, and multiplicity are handled helps readers distinguish planned inference from exploratory findings. Those details are not reported in the registry record. The study is therefore statistically informative as an example of the questions raised by longitudinal binary outcomes, while its comparative findings cannot be evaluated from the reported information.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record does not report the primary-outcome counts by group at any of the listed time points. It also does not provide denominators for analyzable DBS samples, effect estimates, confidence intervals, or p-values. As a result, neither the direction nor the precision of the primary comparison can be assessed from the record.

The endpoint is measured repeatedly, but the analytic treatment of those repeated observations is not described. The record does not state whether the analysis compares each time point separately, models change over time, or uses another summary. The definition of the analysis population, covariate adjustment, missing-data handling, and sensitivity analyses are also not reported.

There is no reported sample-size justification or detailed statistical analysis plan. Although the record lists three analyses and three outcome measures, it does not explain their methods, identify a principal contrast among the repeated assessments, or describe any adjustment for multiple comparisons. Interim analyses are not reported.

The intervention group includes daily text reminders and counseling sessions for a subset with continued adherence challenges. The registry record does not report how that subset was identified or provide results by receipt of counseling, limiting interpretation of the components separately. The record also does not report detailed results for the secondary outcome, retention in PrEP care.

The safety information is limited to counts and listed serious-event terms. Detailed event timing, attribution, and comparative analysis are not reported in the registry record. These limitations concern the information available in the record and should not be taken as evidence that the unreported procedures or analyses were not conducted.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Life-Steps Counseling to Enhance Adherence and Engagement in PrEP Care — NCT04316715.
• Registry record last updated 2026-09-16; status last verified 2026-08.
• Results first posted 2026-09-16.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT04316715, titled Life-Steps Counseling to Enhance Adherence and Engagement in PrEP Care, is listed as a completed randomized, parallel-group trial with no masking. The sponsor is the University of Miami, and enrollment is 300. The record lists a start date of 2020-09-03 and primary completion date of 2025-07-08.

The intervention group received standard of care and daily text message reminders, with 4-6 weekly Lifesteps for PrEP sessions for a subset with continued adherence challenges. The comparator received standard of care without an additional intervention. The primary outcome counts participants with DBS TFV-DP concentrations consistent with 4+ pills per week at 3, 6, 9, 12, 15, and 18 months; participants need an analyzable sample at each time point.

Retention in PrEP care is listed as a secondary outcome. The record reports serious adverse event counts and zero deaths in both groups, but does not report primary-outcome results or a detailed analysis plan. The magnitude and precision of the primary comparison are therefore not reported in the registry record.