Efficacy Testing of a Culturally Relevant Stigma Intervention With WLWH in Tanzania: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy Testing of a Culturally Relevant Stigma Intervention With WLWH in Tanzania (NCT05033002), a randomized na study. The primary outcome is Number of Participants Recruited as Measured by Enrollment Logs.

2. Clinical Question

The study also names internalized stigma, coping self-efficacy, self-esteem, hope, and depressive symptoms among its outcomes. These are relevant to the intervention’s stated focus, but the posted primary endpoint is not an efficacy endpoint. The distinction matters: a randomized comparison of recruitment counts does not answer whether the intervention changes a participant’s score or experience.

The quantitative secondary result described in the registry is a comparison of hope scores at baseline. Because this measurement is explicitly at baseline, it describes scores before the intervention period rather than change attributable to the intervention. The registry record does not report quantitative results for the other named scales in the information available for this analysis.

3. Trial Design

The registry describes a randomized, parallel-group study with no masking. The enrollment was 167, with 80 participants in the Treatment as Usual Group and 87 in the Stigma Intervention Group. The recorded status is completed. The study phase is recorded as NA. Duke University is listed as the sponsor.

The intervention was behavioral. The intervention group was assigned to a 5 week program consisting of weekly ethnodrama segments and guided debriefs using motivational interviewing. The treatment-as-usual group was not to receive a formal stigma-reduction intervention during the study and was to be invited to view the intervention after the follow-up period, without follow-up. Further details about treatment as usual are not reported in the registry record.

The registry lists the study start as 2022-10-24 and primary completion as 2024-05-16. The primary outcome timeframe is up to 6 months. Further details about how individual follow-up was scheduled or completed are not reported in the registry record.

Random assignment is intended to create groups whose differences can be evaluated as an intervention comparison, but the design description alone does not establish that all outcome data were collected or analyzed as planned. The randomization method, allocation concealment, analysis population, handling of missing outcomes, and detailed statistical analysis plan are not reported in the registry record. With no masking, participants and study personnel were not described as masked; whether outcome assessors or analysts were masked is not reported in the registry record.

The recorded enrollment counts describe participants assigned to the two groups, and the primary outcome counts match those group sizes. Those counts should not be mistaken for evidence about treatment effects on stigma or other psychological outcomes. The posted data on those outcomes need to be considered separately, including whether they are baseline measurements or post-intervention changes.

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 Recruited as Measured by Enrollment Logs, measured over up to 6 months.

The primary endpoint is the number of participants recruited, measured by enrollment logs over a timeframe of up to 6 months. It addresses a practical study question: how many participants entered the trial during the stated recruitment period. Recruitment counts can help describe whether a study enrolled participants, but they do not measure the intervention’s effect on stigma, hope, self-efficacy, self-esteem, or depressive symptoms.

The registry reports 80 participants in the Treatment as Usual Group and 87 in the Stigma Intervention Group, for an enrollment of 167. The comparison is represented as a risk difference of 0.0 with p=1.0. In the posted coding for this endpoint, the number recruited equals the group size in both arms. Consequently, the comparison does not distinguish recruitment between the groups in a way that evaluates an intervention effect on a participant outcome.

Recruitment count is useful for describing enrollment against a study’s recruitment needs. However, the registry record does not report a recruitment target, recruitment rate, or a target-based assessment of whether recruitment was successful. It also does not report a separate primary clinical or psychosocial outcome result. The endpoint should therefore be read narrowly as a count of enrollment, not as a test of stigma reduction or overall efficacy.

7. Results Posted in the Registry

• Stigma Intervention Group: 100.0% (87/87) versus 100.0% (80/80) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Hope, as Measured by the Swahili Version of the State of Hope Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Stigma Intervention Group: mean 15.82 versus 15.48 on control; difference 0.34 (95% CI -0.66 to 1.34), standardized effect d = 0.10; z-test p = 0.506.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Stigma Intervention Group and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcome domains listed by the registry span internalized stigma, coping self-efficacy, self-esteem, hope, and depressive symptoms. The numerical result described in detail is a baseline hope comparison. A baseline result can describe how the randomized groups’ scores compare before the intervention period, but it does not show whether either group changed afterward or whether changes differed between groups.

For the other named domains, quantitative results are not reported in the registry record for this analysis. Therefore, a cross-outcome pattern—such as whether measures moved consistently in a particular direction—cannot be assessed from the reported numerical results. It would be inappropriate to infer such a pattern from the intervention’s aims, the outcome names, or the recruitment endpoint.

The primary endpoint measures recruitment rather than a participant-level psychosocial outcome. Its result cannot serve as corroboration of the secondary outcomes: successful or completed recruitment does not show that stigma, hope, coping, self-esteem, or depressive symptoms changed. Conversely, the baseline hope comparison does not answer the primary recruitment question.

General explanation: secondary analyses are often less conclusive than a clearly prespecified primary analysis, particularly when many outcomes or comparisons are examined. Multiple testing can increase the chance of observing a seemingly notable result by chance unless the analysis plan addresses it. The registry record lists 10 outcome measures and 9 analyses, but a multiplicity strategy is not reported in the registry record. The baseline p-value is unadjusted, and results for the other named outcomes are not available in the reported information. It should therefore be treated as limited descriptive evidence, not a standalone claim about intervention efficacy.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Change in Internalized Stigma, as Measured by the Swahili Version of the Multidimensional Measure of Internalized Stigma Scale
• Change in Coping Self-efficacy, as Measured by the Swahili Version of the Coping Self-Efficacy Scale
• Change in Self-esteem, as Measured by the Swahili Version of the Rosenberg Self-Esteem Scale
• Hope, as Measured by the Swahili Version of the State of Hope Scale
• Change in Depressive Symptoms, as Measured by the Swahili Version of the Patient Health Questionnaire 9

9. Statistical Interpretation

10. Statistical Methods Explained

What does a randomized parallel-group design mean?

General explanation: in a randomized parallel-group design, participants are allocated to one of the study groups and remain in that assigned group for the comparison. Random assignment can reduce systematic differences between groups at the start, on average, but it does not guarantee that the groups are identical. The registry describes this study as randomized and parallel, but the method of sequence generation and allocation concealment is not reported in the registry record.

There was no masking listed. General explanation: masking is intended to limit the influence of knowledge about assignment on participant reports, study procedures, or outcome assessment. The registry does not describe which people, if any, beyond participants and intervention personnel were aware of assignments, so further conclusions about masking cannot be drawn.

What does the primary comparison test?

The primary endpoint is a count of participants recruited. The posted comparison expresses this using a risk-difference format, but the underlying quantities are recruitment counts: 80 of 80 in the Treatment as Usual Group and 87 of 87 in the Stigma Intervention Group. This coding yields a risk difference of 0.0 and p=1.0. These figures reflect that each group’s recruited count equals the corresponding group size. They are not an estimate of a difference in stigma or another clinical outcome.

General explanation: a risk difference usually compares the proportions of participants with an event between groups. Its meaning depends on what is defined as the event and on the denominators. Here, the endpoint is recruitment itself, and the group-specific counts used in the comparison do not provide a treatment-response measure. Thus, the format should not lead readers to interpret the result as evidence for or against a stigma-reduction effect.

How should the baseline hope analysis be read?

The registry reports a two-sided t-test for a mean difference in final values, with a stated mean difference of 0.34 and p=0.506. The outcome is identified as Hope, measured at baseline, on a scale. The means are 15.48 in the Treatment as Usual Group and 15.82 in the Stigma Intervention Group. These are group summaries at baseline, not before-and-after changes.

General explanation: a two-sample t-test evaluates whether the observed difference in group means is compatible with a null hypothesis of no difference, under assumptions about the data and sampling process. A p-value is not the probability that the null hypothesis is true and does not establish that the groups are exactly alike. The registry reports the test and p-value, but details of model diagnostics or any adjustments are not reported in the registry record.

The unadjusted confidence interval associated with the posted summary statistics crosses zero. General explanation: for a mean difference, zero represents no difference between group means. An interval spanning zero therefore includes both directions of difference and no difference. This is uncertainty about the baseline contrast, not an interval for an intervention effect over time.

What is the role of the planning illustration?

The planning illustration uses the observed baseline hope difference as its reference effect and gives participant counts per arm for 80% and 90% power under stated assumptions: two-sided significance level 0.05, equal allocation between arms, and a normal approximation. It also considers planning for 75% and 50% of the observed effect. These are planning illustrations, not the trial’s observed power and not evidence that the trial was designed around those assumptions. The trial’s own sample-size justification is not reported in the registry record.

General explanation: power calculations estimate how often a specified design would detect an effect of a chosen size if that effect were real and the model assumptions held. Such calculations are sensitive to the effect size chosen. Using an effect observed in a small or particular dataset can give an unstable planning basis, and using a baseline contrast does not make that contrast a treatment effect. The listed planning counts should therefore be read as hypothetical design illustrations, not as a retrospective measure of success.

What analysis details remain unknown?

The registry record does not report the primary statistical analysis plan, any prespecified covariate adjustments, interim analyses, the method used for missing data, or which analysis population was used for each outcome. The number of outcome measures and analyses is listed, but that does not disclose how the analyses were selected or whether all were planned before data were examined. These omissions limit assessment of analytic choices and of how completely the posted results represent the intended outcome set.

General explanation: complete interpretation of a randomized trial usually depends on knowing the analysis population, outcome timing, missing-data handling, and whether comparisons were prespecified. These details affect the estimates’ meaning and the credibility of inferences. Their absence in the registry record does not establish that a particular method was or was not used; it means that method is not reported in the registry record.

11. Confidence Intervals and Precision

The registry’s baseline hope comparison gives a mean difference of 0.34. The unadjusted confidence interval derived from the posted summary statistics crosses zero, so it includes a range of possibilities that allows for a difference in either direction as well as no difference. The two-sided t-test p-value is 0.506. Together, these statistics do not establish a clear baseline difference, and they do not estimate a change caused by the intervention.

General explanation: a confidence interval describes a range of values compatible with the data and the method used to calculate it. A wide interval indicates limited precision; an interval crossing the null value indicates that the data do not rule out no difference at the stated confidence level. The interval’s interpretation depends on the analysis and its assumptions. The registry does not provide a confidence interval in its reported t-test entry, so the interval described for the mean difference is an unadjusted calculation from the posted group summaries, not a registry-reported interval.

For recruitment, the registry comparison gives a risk difference of 0.0 and p=1.0. Because the endpoint is the number recruited and the registered count equals the group size for each arm, this comparison is not informative about precision for an intervention effect on a participant outcome. No uncertainty interval for a clinical or psychosocial treatment effect is reported in the registry record.

The group sizes and baseline standard deviations help describe the available information for the baseline score, but they do not resolve the broader limitation that post-intervention outcome estimates are not reported in the registry record. Precision cannot be inferred for those missing treatment-effect estimates.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 9 analyses. It identifies several secondary domains, but the multiplicity strategy—if any—is not reported in the registry record. The record does not state whether a particular outcome family was treated as confirmatory, whether p-values were adjusted, or whether a hierarchy of testing was prespecified. The reported baseline hope p-value is a two-sided t-test result; it is not identified as multiplicity-adjusted.

General explanation: when many statistical tests are conducted, the chance of at least one apparently unusual result can rise, even if none of the underlying effects is real. Adjustment methods or prespecified testing hierarchies can address this issue, but the appropriate approach depends on the trial’s aims and analysis plan. Without a reported plan, the strength of evidence from isolated secondary tests is difficult to evaluate.

Missing-data procedures and analysis populations are also not reported in the registry record. The posted group sizes are available, but the record does not state how many participants contributed data to each secondary analysis, whether all randomized participants were included, or how missing measurements were handled. It does not report whether analyses followed an intention-to-treat principle or used another population definition.

General explanation: missing outcomes can affect estimates if the participants with observed data differ systematically from those without observed data. Analysis populations also shape the question answered by an estimate. These considerations are especially important for repeated or follow-up measures, but the registry record does not provide enough information to assess them for the named psychological outcomes.

The registry record also does not report the detailed statistical analysis plan, interim analyses, or whether secondary analyses were prespecified. These absences do not show that no plan or procedures existed; they mean the relevant details are not reported in the registry record. Accordingly, interpretation should avoid treating the available secondary statistic as a complete account of the planned outcome analyses.

13. 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 record lists zero serious adverse events and zero other adverse events in the Treatment as Usual Group, with 80 participants at risk. It also lists zero serious adverse events and zero other adverse events in the Stigma Intervention Group, with 87 participants at risk. No deaths are listed in either group.

These are recorded counts, not proof that no adverse events occurred outside the registry’s collection or reporting procedures. The registry record does not report the event definitions, the method or frequency of safety monitoring, the observation period for these counts, or whether the adverse-event information was collected in a way that could identify all events. It also lists no serious adverse-event terms.

General explanation: zero recorded events can occur when no events happen, when events are not detected, or when they are not reported under the applicable procedures. The counts should therefore be read as the safety information posted in the registry, rather than as a guarantee of absence of risk. These figures do not establish a comparative safety profile beyond the reported counts.

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

The posted primary result means that the trial enrolled 167 participants, with 80 in the Treatment as Usual Group and 87 in the Stigma Intervention Group. The primary endpoint is a recruitment count, and its posted comparison does not measure whether the intervention changes stigma or other psychosocial outcomes. The risk difference of 0.0 and p=1.0 should not be described as evidence that the intervention has no effect on those outcomes.

The baseline hope result describes a difference between group means before the intervention period. It is not a treatment-response estimate, and its p-value does not show that the groups are exactly equivalent. The unadjusted interval spanning zero indicates uncertainty around the baseline contrast. The registry record does not report quantitative post-intervention results for the named psychosocial outcomes in the information analyzed.

These results also do not establish whether recruitment met a prespecified target, because a target and target-based evaluation are not reported in the registry record. Nor do the adverse-event counts establish that the intervention has no risks; they describe only the events recorded in the registry.

General explanation: a treatment-effect conclusion ordinarily requires a clearly defined participant outcome, a comparison at the relevant follow-up time, and an analysis that accounts for the trial design and available data. Without a reported post-intervention contrast for the outcomes of interest, that kind of conclusion cannot be drawn from the recruitment count or baseline score. The absence of a reported result should not be interpreted as proof of no effect; it means the effect is not reported in the registry record.

The most defensible reading is therefore narrow. The record describes a completed randomized study and its enrollment, intervention, comparator, and selected outcome domains. Its posted quantitative information supports a description of recruitment and a baseline hope comparison, but does not provide a reported estimate of intervention-related change in stigma or the other listed psychosocial measures.

15. Why This Trial Matters Statistically

This study illustrates why the endpoint’s definition matters as much as the statistical result. A recruitment count can describe how many people entered a study, but a comparison expressed in a familiar format such as a risk difference does not become an efficacy analysis unless the underlying event represents a participant outcome relevant to the intervention question. Here, recruitment is the registered primary outcome, while the intervention’s stated focus concerns stigma reduction.

The record also makes the timing of a measurement important. Hope is among the named outcomes, and a baseline comparison is posted. A baseline measure helps describe the groups before intervention exposure; it is not a measure of change. Treating it as an efficacy result would confuse group description with a treatment effect.

For biostatisticians and clinical researchers, the record highlights the value of transparent reporting on outcome timing, analysis populations, missing data, multiplicity, and the prespecified analysis plan. Without these details and without post-intervention estimates for the named psychosocial outcomes, readers cannot assess the intended efficacy questions or the robustness of secondary findings.

The planning illustration also shows why sample-size calculations need careful framing. It is based on an observed baseline contrast and stated assumptions, rather than being a report of the trial’s design justification or observed power. Planning figures can be informative as hypothetical scenarios, but their relevance depends on choosing a defensible target effect and clearly distinguishing that target from an observed estimate.

16. 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 is the mismatch between the study’s stated intervention focus and its registered primary endpoint. Recruitment count does not measure stigma reduction or change in the other psychosocial outcomes. The posted comparison is consequently not evidence of an intervention effect on those outcomes.

The quantitative secondary result described is measured at baseline, rather than as a post-intervention change. Quantitative results for the other named outcome domains are not reported in the registry record. This prevents assessment of whether the intervention groups differed over time on stigma, coping self-efficacy, self-esteem, hope, or depressive symptoms.

The registry does not report details needed to assess the analytic approach fully, including the analysis populations, missing-data handling, multiplicity strategy, randomization method, or detailed statistical plan. Follow-up details beyond the primary outcome timeframe and intervention description are not reported in the registry record. Participant characteristics and further eligibility information are also not reported in the registry record.

The planning illustration is based on the observed baseline hope difference, not a reported intervention effect or the trial’s own design assumptions. It should not be used to infer observed power or to judge the adequacy of the trial’s original sample size. The registry record does not report a sample-size justification.

Finally, the adverse-event record contains zero events in both groups, but details about collection, definitions, and observation are not reported in the registry record. The absence of reported events should be interpreted in that reporting context and not as proof that no risk exists.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Efficacy Testing of a Culturally Relevant Stigma Intervention With WLWH in Tanzania — NCT05033002.
• Registry record last updated 2025-05-29; status last verified 2025-05.
• Results first posted 2025-05-29.
• 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.

20. Record Summary

NCT05033002 is a completed randomized, parallel-group study with no masking listed, sponsored by Duke University. The registry records enrollment of 167 participants: 80 assigned to treatment as usual and 87 assigned to the Labda Siku Moja stigma-reduction intervention. The intervention involved weekly ethnodrama segments and guided debriefs over 5 weeks.

The registered primary outcome is the number of participants recruited over a timeframe of up to 6 months. Its posted comparison is a risk difference of 0.0 with p=1.0; this is a recruitment result, not an efficacy estimate. A baseline hope comparison is also reported, but it does not measure intervention-related change. Quantitative results for the other named psychosocial outcomes are not reported in the registry record.

The registry lists zero serious and zero other adverse events in each group. Further statistical-plan, missing-data, and safety-monitoring details are not reported in the registry record.