A Pilot Trial of Perinatal Depression Treatment in HIV Infected Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Pilot Trial of Perinatal Depression Treatment in HIV Infected Women (NCT04094870), a randomized phase 4 study. The primary outcome is Number of Women Retained in the Study.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group pilot trial registered as NCT04094870. The registry lists the trial as Phase 4, with no masking. It reports enrollment of 80 and shows 40 participants assigned to each treatment arm. The two assigned approaches were antidepressant medication, specifically sertraline, and interpersonal therapy. The registry describes the study as using quantitative and qualitative methods to assess feasibility and acceptability in postpartum women with HIV who were taking antiretroviral therapy.

The study took place at several clinics in Lusaka, Zambia. The registry gives a start date of 2019-10-30 and a primary completion date of 2020-10-30, and lists the status as completed. The primary outcome timeframe runs from enrollment to a final visit approximately 24 weeks after enrollment. The interpersonal therapy arm is described as having up to 11 planned sessions during a 24-week period beginning on the day of randomization. The medication arm is described as daily self-administered sertraline, a selective serotonin reuptake inhibitor.

The main trial result concerns retention: the registry reports that 39 participants in each group completed the final study visit. Outcome summaries also include symptom-score changes, adverse events, adherence, acceptability, and change in viral load. The registry lists 12 outcome measures, while seven secondary outcomes are posted in the available results. A fuller description of the randomization procedure, concealment, treatment delivery, qualitative methods, and analysis populations is not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

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 Women Retained in the Study, measured over Enrollment - final visit, approximately 24 weeks after enrollment.

The primary endpoint is the number of enrolled women who completed the final study visit. The registry specifies that the visit was expected approximately 24 weeks after enrollment. It is therefore a retention outcome: it counts completion of the study visit rather than directly measuring depression symptoms, treatment adherence, viral load, or treatment acceptability.

The posted results report 39 completions among 40 participants in the antidepressant medication group and 39 among 40 in the interpersonal therapy group. The unadjusted risk difference for interpersonal therapy compared with antidepressant medication is 0.0. The registry also reports an unadjusted p-value of 1.0. These summaries indicate that the observed completion counts were the same in the two randomized groups. The confidence interval is reported as extending on both sides of zero, so the estimate is compatible with differences in either direction; its numerical bounds are not repeated because they exceed the stated display precision limit.

Retention is commonly used as a feasibility indicator in pilot studies (general statistical context). It can show whether participants completed the planned follow-up, but it is not by itself a direct measure of whether the treatments were acceptable or whether depression improved. The registry’s secondary outcomes address some of those other questions. The record does not describe a specific retention threshold for judging feasibility, so no pass-or-fail criterion can be inferred.

7. Results Posted in the Registry

• Interpersonal Therapy: 97.5% (39/40) versus 97.5% (39/40) on control; risk difference 0.0 percentage points (95% CI -6.8 to 6.8), risk ratio 1.00 (0.93–1.07); unadjusted two-proportion z-test p = 1.000.

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.

Number of Women With an EPDS Score Decline of 3 Points From Baseline

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Interpersonal Therapy: 100.0% (39/39) versus 94.9% (37/39) on control; risk difference 5.1 percentage points (95% CI -1.8 to 12.1), risk ratio 1.05 (0.98–1.13); unadjusted two-proportion z-test p = 0.152.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Interpersonal Therapy and the control. The interval gives the range of effects that remain compatible with the data.

Number of Women With a CGI Score Decline of One Point From Baseline

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Interpersonal Therapy: 100.0% (39/39) versus 97.4% (38/39) on control; risk difference 2.6 percentage points (95% CI -2.4 to 7.5), risk ratio 1.03 (0.98–1.08); unadjusted two-proportion z-test p = 0.314.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Interpersonal Therapy and the control. The interval gives the range of effects that remain compatible with the data.

Changes in the Viral Load Between Study Entry and the Last Visit

• 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:
  • Interpersonal Therapy: mean 1.60 versus 0.60 on control; difference 1.00 (95% CI -0.71 to 2.71), standardized effect d = 0.26; z-test p = 0.252.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Interpersonal Therapy and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes broaden the focus beyond retention. They include counts tied to changes in depression-related scores, medication toxicity and adherence, adherence to interpersonal therapy, acceptability of trial participation, and change in viral load. This range reflects the study’s stated interest in feasibility and acceptability as well as clinical and treatment-related measures. The posted outcomes use different definitions and scales, so they should be interpreted as separate pieces of descriptive evidence rather than as one combined measure.

Across these outcomes, the registry does not report a full set of statistical analyses. The available group summaries and unadjusted comparisons can suggest patterns, but they do not establish a consistent treatment advantage across outcome domains. Some outcomes are counts of participants meeting thresholds; others address adverse events or continuous viral-load change. Differences in denominator, measurement, and uncertainty make a single overall conclusion inappropriate.

The primary result concerns final-visit completion, not symptom change or viral load. Secondary findings therefore complement the retention result rather than redefining it. They may provide additional context about whether trial participation and treatment delivery were feasible, but the registry record does not provide a prespecified framework for combining these results into one feasibility judgment.

Unadjusted secondary comparisons carry less weight than a single prespecified primary outcome because multiple outcomes create more opportunities for chance findings. General statistical context: when multiple tests are interpreted together without adjustment or a defined hierarchy, isolated small p-values can be misleading. The registry record does not report multiplicity control or a plan that distinguishes confirmatory from exploratory secondary analyses. The secondary results are best read as exploratory descriptions that can inform further study, rather than as definitive evidence on their own.

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

• Number of Women With an EPDS Score Decline of 3 Points From Baseline
• Number of Women With a CGI Score Decline of One Point From Baseline
• Percentage of Women Experiencing Anti Depressant Medication Toxicity
• Percentage of Women Who Adhere to the Prescribed Antidepressant Medication (ADM)
• Number of Women Who Adhere to the Interpersonal Therapy Arm (IPT)
• Acceptability of Trial Participation for Treatment of Postpartum Depression
• Changes in the Viral Load Between Study Entry and the Last Visit

9. Statistical Interpretation

10. Statistical Methods Explained

The primary comparison is a difference in the proportion completing the final study visit. A risk difference expresses the difference between two group proportions in the outcome of interest. A value of 0.0 means that the observed proportions are equal. In this trial, the reported completion counts are equal as well: 39 of 40 in each group. This is an unadjusted comparison, meaning the posted summary does not account for other participant characteristics through a statistical adjustment.

What does a confidence interval describe?

General statistical explanation: a confidence interval communicates uncertainty around an estimated effect. It shows a range of values compatible with the data under the method used to construct it. An interval that includes zero for a difference does not establish that the true difference is zero; it indicates that the data do not exclude zero under that interval method. An interval extending to both negative and positive values can also be consistent with effects in either direction. The registry record does not report the confidence-interval construction method or confidence level, so those details should not be assumed.

How should the p-value be read?

General statistical explanation: a p-value describes how unusual data at least as discrepant as those observed would be under a specified null model. It is not the probability that the null hypothesis is true, nor is it a measure of the size or importance of an effect. The primary result has a reported unadjusted p-value of 1.0. That value accompanies an estimated risk difference of 0.0 and equal observed counts. It does not demonstrate equivalence or show that a meaningful difference is impossible.

How do the secondary outcome summaries differ?

The posted symptom outcomes are counts of participants meeting a stated score-change threshold. Their comparisons use risk differences, which contrast group proportions. Viral-load change is a continuous outcome reported as a mean and standard deviation in each group, with a mean difference used for the comparison. A mean summarizes the central value of a distribution; a standard deviation describes the spread of individual values around that mean. These summaries answer different questions and should not be treated as interchangeable.

General statistical explanation: mean-based summaries can be sensitive to skewness or unusually extreme observations, while counts and proportions have their own limitations, including dependence on the selected threshold. The registry does not report distribution checks, adjusted models, or further details of the analysis methods for these secondary outcomes. It is therefore not possible to assess from the registry record whether alternative models or assumptions were considered.

What does unadjusted mean for the secondary comparisons?

The registry posts unadjusted comparisons for the secondary outcomes. General statistical explanation: when several outcomes are examined, each unadjusted test is interpreted without accounting for the number of other tests. If many comparisons are considered, the chance of at least one apparently noteworthy result can increase. Adjustment methods can address some multiplicity concerns, but the registry record does not report a correction method or a prespecified hierarchy for interpreting secondary outcomes. The listed unadjusted p-values should therefore be regarded as exploratory rather than as stand-alone confirmatory evidence.

How should the planning illustration be understood?

The registry includes a sample-size planning illustration based on the observed viral-load effect, not on the trial’s own design assumptions. It describes equal allocation, a two-sided significance level of 0.05, a normal approximation, and planning for the stated fractions of the observed effect. For 100% of the observed effect, the illustration gives 234 participants per arm for 80% power and 312 participants per arm for 90% power. For 75% of the observed effect, it gives 415 participants per arm for 80% power and 555 participants per arm for 90% power. For 50% of the observed effect, it gives 933 participants per arm for 80% power and 1,248 participants per arm for 90% power.

These are planning illustrations, not observed power and not evidence that this pilot was designed to detect the listed effects. They are based on an effect estimated from the posted viral-load results, so they inherit uncertainty in that estimate. The registry does not report the trial’s own sample-size justification. General statistical context: planning calculations depend on the chosen effect, variability assumptions, error rate, and analysis method; changing those assumptions changes the resulting sample-size estimate.

11. Confidence Intervals and Precision

The primary estimate is a risk difference of 0.0, based on 39 final-visit completions among 40 participants in each group. The registry reports a confidence interval with a negative lower bound and a positive upper bound. The interval therefore includes zero and allows for possible differences in either direction. The numerical bounds are not reproduced because the registry values have more than three decimal places.

A point estimate alone does not convey precision. The interval gives a sense of how much uncertainty remains around the estimate, while the equal observed counts describe only what happened in this trial. The interval is not so narrow that it establishes the two groups’ underlying retention as identical. The registry does not report a confidence level or the method used to calculate the interval, so those features cannot be specified.

The trial’s pilot nature and the number of observed outcomes also matter to interpretation. The primary outcome is a count over a relatively small randomized group, and the secondary outcomes use their own denominators and scales. The viral-load comparison, for example, is expressed as a mean difference with a confidence interval that crosses zero. Its planning illustration requires substantially larger per-arm samples for the listed power targets, but those are planning figures based on the observed effect, not a retrospective statement about the trial’s power.

General statistical context: a wide interval indicates limited precision, while a narrow interval indicates greater precision under the method used. Neither width nor whether an interval includes zero determines clinical importance on its own. Judging importance also requires a meaningful threshold, which is not reported in the registry record for retention or the other outcomes.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and several secondary outcomes, including symptom-score thresholds, adverse events, treatment adherence, acceptability, and viral-load change. It does not report a statistical analysis plan specifying how these outcomes were prioritized beyond the stated primary outcome. A prespecified hierarchy or multiplicity adjustment is not reported in the registry record.

Multiplicity matters because each additional statistical comparison creates another opportunity for a result to appear notable by chance. General statistical context: adjustment procedures or a clear outcome hierarchy can help control how several tests are interpreted. Without reported adjustment, secondary p-values should be treated as unadjusted and exploratory. The registry lists no reported analyses for the secondary outcomes, further limiting the basis for confirmatory interpretation.

The record does not describe how missing outcome data were handled, whether analyses followed intention-to-treat principles, or whether a per-protocol population was defined. The primary outcome itself records completion of the final visit, but the registry does not report how participants without a final visit were handled in analyses of other outcomes. Secondary results use 39 participants per group for several measures, while the primary retention outcome starts from 40 assigned per group. Reasons for the differing denominators and any imputation procedures are not reported in the registry record.

Detailed analysis populations, exclusions, missingness patterns, and sensitivity analyses are also not reported in the registry record. These omissions do not negate the posted summaries, but they limit assessment of whether the analyzed participants represent all randomized participants and whether missing data could affect the secondary comparisons. The record does not report interim analyses or stopping rules; their presence or absence should not be inferred.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event summaries list zero serious adverse events among 40 participants at risk in each treatment group. They also list 9 other adverse events among 40 at risk in each group, with zero deaths in each group. These are registry-record counts, not a detailed account of event types, severity, timing, or causal attribution.

The summary does not establish that the treatment groups have identical safety profiles. Counts in a pilot study provide limited precision, and the record does not report confidence intervals or a statistical comparison for these safety figures. The serious-event terms list is empty, and details about the nine other events in each group are not reported in the registry record. The separate secondary outcome concerning antidepressant medication toxicity is listed, but a result for that outcome is not included among the posted secondary summaries described in the record.

General statistical context: adverse-event counts are most informative when accompanied by definitions, event descriptions, follow-up duration, and assessment procedures. Without those details, the posted figures can be read only as the recorded counts for the stated groups and at-risk denominators.

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

The primary result shows equal observed retention counts in the two randomized groups: 39 participants completed the final visit in each group, from 40 assigned to each. The reported risk difference is 0.0, and the unadjusted p-value is 1.0. These findings describe the observed trial data and do not show a difference in final-visit completion between the groups.

The result does not prove that the treatments have identical retention rates. The confidence interval extends to both sides of zero, leaving room for differences in either direction. The record does not provide a predefined equivalence margin or feasibility threshold, so the result cannot be classified against such a criterion.

Retention is only one aspect of feasibility. The study also planned to assess acceptability, treatment adherence, medication toxicity, symptom-score changes, and viral-load change. Those outcomes address different questions, and their posted summaries do not turn the retention measure into a direct measure of depression response or overall treatment acceptability. The registry record does not report enough detail to establish how all quantitative and qualitative evidence was combined.

These results do not establish whether either treatment is effective, ineffective, safer, or preferable for individuals. They describe outcomes in this pilot trial and should not be generalized beyond the population and setting studied without further evidence. Detailed participant characteristics, eligibility criteria, and some analysis methods are not reported in the registry record, limiting assessment of how broadly the findings may apply.

The viral-load planning figures likewise should not be mistaken for observed trial conclusions or observed power. They are sample-size illustrations calculated from the observed effect under stated assumptions. They indicate what those assumptions imply for future planning, not what a larger study would necessarily find.

15. Why This Trial Matters Statistically

This trial illustrates why a pilot study’s primary outcome may concern whether participants complete follow-up rather than whether a treatment changes a clinical measure. Retention is a practical component of feasibility, and the posted completion counts are directly interpretable as study follow-up outcomes. The result is therefore relevant to the trial’s stated feasibility focus, while remaining distinct from symptom change, treatment adherence, acceptability, or viral load.

It also shows the difference between an equal point estimate and a precise estimate. Both groups had the same observed completion count, and the risk-difference estimate is 0.0. Yet the confidence interval crosses zero and includes possible differences in either direction. The absence of an observed difference is not the same as evidence of equivalence; a study needs an appropriate design and a prespecified margin to support an equivalence claim, and no such margin is reported.

The range of secondary outcomes highlights another statistical issue: a study may collect several kinds of evidence, each with distinct denominators, scales, and interpretations. Unadjusted comparisons across multiple outcomes require caution, particularly when the registry does not report a multiplicity plan or detailed analysis methods. The pilot’s results are informative as descriptive estimates, but they do not carry the same confirmatory weight as a prespecified primary analysis.

Finally, the sample-size illustration makes clear that planning depends on the effect chosen for detection and the assumptions used. Because the illustration is based on the observed viral-load effect, it is not a justification for the completed trial’s enrollment and not a measure of its observed power. The registry does not report the trial’s own sample-size rationale.

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 registry record leaves important aspects of the trial methods and population undescribed. Detailed eligibility criteria, participant characteristics, the randomization procedure, allocation concealment, treatment fidelity, and the conduct of the qualitative methods are not reported in the registry record. These details would help readers assess implementation and the applicability of the findings.

The primary outcome is limited to final-visit completion. It does not directly measure symptom response, treatment acceptability, or treatment adherence. Although the registry lists those areas among secondary outcomes, it does not provide a complete set of reported analyses or a framework for integrating them into an overall feasibility assessment. The specific feasibility threshold, if any, is not reported in the registry record.

The registry does not report how missing data were handled, why some secondary outcome denominators differ from the primary outcome group sizes, or which analysis populations were used. The confidence-interval method and confidence level are also not reported. The record does not provide a prespecified multiplicity strategy, detailed statistical analysis plan, or reported secondary analyses.

The adverse-event summary gives counts but not event descriptions or details about seriousness assessment, timing, or attribution. The sample-size illustration is based on the observed viral-load effect rather than a reported design justification, and it cannot resolve uncertainty in that effect. These limitations constrain the conclusions that can be drawn from the posted registry summaries.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: A Pilot Trial of Perinatal Depression Treatment in HIV Infected Women — NCT04094870.
• Registry record last updated 2021-11-10; status last verified 2020-12.
• Results first posted 2021-11-10.
• 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

NCT04094870 is a completed, randomized, unmasked, parallel-group Phase 4 pilot trial of antidepressant medication compared with interpersonal therapy for postpartum women with HIV-1 infection and perinatal depression. The registry describes the participants as receiving antiretroviral therapy and the study setting as several clinics in Lusaka, Zambia. Enrollment was 80, with 40 assigned to each group.

The primary outcome was completion of the final study visit approximately 24 weeks after enrollment. The registry reports 39 completions in each group, a risk difference of 0.0, and an unadjusted p-value of 1.0. Secondary outcomes include symptom-score changes, treatment adherence, acceptability, adverse events, and viral-load change. The record does not report a full secondary analysis plan, missing-data procedures, or a sample-size justification for the trial.