Feasibility & Acceptability of a Virtual Sister Circle Intervention for Black Women With Depressive Symptoms: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Feasibility & Acceptability of a Virtual Sister Circle Intervention for Black Women With Depressive Symptoms (NCT04837573), a non-randomized na study. The primary outcome is Completion and Retention Rates of Participants as Measures of Feasibility.

2. Clinical Question

The study is registered as an evaluation of feasibility and acceptability for Black women with depressive symptoms. Its primary endpoint is specifically titled around completion and retention rates, so the registry’s primary question is whether participants complete enough sessions and remain in the study under the stated definitions. The record does not report numerical completion or retention results, nor does it describe a separate primary measure of acceptability.

A secondary outcome is change in psychological flexibility from baseline to 6 weeks. The registry record does not report the result for that outcome. Because allocation is nonrandomized and the groups receive the intervention during different periods, comparisons between them would not by themselves establish that any outcome difference was caused by the intervention.

3. Trial Design

The registry record identifies this as a completed, nonrandomized, parallel-model study of a behavioral intervention. Enrollment is listed as 30. The study start date is 2022-09-14, and the primary completion date is 2023-04-02. The record lists no masking.

The intervention is the Sister Circle protocol. The arm descriptions state that Group 1 receives the intervention during Weeks 1-8 while Group 2 receives no treatment, followed by Group 2 receiving the intervention during Weeks 9-16 while Group 1 receives no treatment. This is a staggered schedule in which the groups have different intervention periods, rather than a randomized, simultaneous comparison of treatment and control.

The adverse-event entries use different period labels: Group 1 Intervention, Weeks 1-6, and Group 2 Intervention, Weeks 7-12. These labels do not match the Weeks 1-8 and Weeks 9-16 schedule in the arm descriptions. The registry record does not explain this difference, so the timing should not be treated as reconciled.

The primary outcome timeframe is listed as 12 weeks, while the arm descriptions extend through Weeks 16. The record does not explain how that endpoint timeframe relates to the intervention schedule. It also does not report the allocation process beyond identifying it as nonrandomized, or provide further details about treatment delivery, adherence procedures, or the basis for the schedule.

The registry record describes the study purpose as evaluating feasibility and acceptability. It lists 4 outcome measures and 0 analyses. Numerical results for the primary and secondary outcomes are not reported in the registry record, so the study design can be described but outcome performance cannot be assessed from the recorded information.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Completion rates were calculated for participants who were able to meet during the time the sessions were held. Retention rates were calculated for all enrolled participants.

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 Completion and Retention Rates of Participants as Measures of Feasibility, measured over 12 weeks.

The primary endpoint is completion and retention, used as measures of feasibility. Completion is defined as the number of participants who attended 4+ sessions divided by the participants available to attend 4+ sessions. Retention is defined as the number retained divided by the number enrolled. The listed timeframe is 12 weeks.

These measures address whether participants can take part in the intervention and remain in the study, rather than whether depressive symptoms improve. The completion denominator is restricted to participants able to meet during the session times, whereas the retention denominator includes all enrolled participants. Those definitions represent different aspects of feasibility and should not be treated as interchangeable.

Completion depends on session attendance, and the threshold of 4+ sessions makes it an operational measure of participation. Retention captures continued participation under the study’s definition. Neither measure, by itself, describes why a participant did or did not attend or remain in the study. The registry record does not report the observed completion or retention percentages, the counts used to calculate them, or the handling of participants with incomplete follow-up.

Although the study purpose includes acceptability, the listed primary endpoint is completion and retention. The record does not give a separate acceptability endpoint or its result. It also lists change in psychological flexibility from baseline to 6 weeks as a secondary outcome, but does not report that result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation depends on how an outcome is defined, how its denominator is chosen, and what comparison the design can support. In this study, the primary outcome is a pair of feasibility measures—completion and retention—not a symptom score or a randomized treatment-effect estimate. The registry record does not report numerical results or an analysis method, so statistical concepts can clarify what the measures would represent without implying that a particular analysis was performed.

What does a percentage measure?

A percentage expresses a count relative to a defined denominator. For completion, the numerator is participants who attended 4+ sessions, and the denominator is participants available to attend 4+ sessions. For retention, the numerator is participants retained, and the denominator is all enrolled participants. Because the denominators differ, the percentages answer different questions. A completion percentage is about attendance among those able to meet at the scheduled times; a retention percentage is about remaining in the study among those enrolled.

Denominator definitions matter especially when participation opportunities differ. Excluding participants unable to attend from the completion denominator means that the measure does not represent attendance among every enrolled participant. Retention instead includes all enrolled participants by definition. The record does not give the actual numerator and denominator counts, so neither percentage can be reproduced or checked from the information recorded for this trial.

What would uncertainty add?

A confidence interval is a range of values compatible with the observed data under a specified statistical procedure. It communicates precision as well as an estimate: a narrower interval indicates greater precision under that method, while a wider interval indicates more uncertainty. For a percentage, the interval also depends on the number of observations and the method used to calculate it. The registry record does not report confidence intervals or enough outcome counts to calculate them.

A p-value, when used, evaluates how compatible data are with a specified null hypothesis under a statistical model. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. No p-values or analysis results are reported in the registry record. The absence of an analysis result means statistical significance cannot be assessed from this record.

How does nonrandomized allocation affect comparisons?

Randomization, when used, aims to make comparison groups similar on average with respect to measured and unmeasured characteristics. This record identifies allocation as nonrandomized. Therefore, group comparisons may reflect pre-existing differences or other factors associated with group membership, in addition to any intervention-related difference. Adjustment methods can address some measured differences in some settings, but the registry record does not report an adjusted analysis or describe a method for controlling confounding.

The schedule also places intervention and no-treatment periods at different times. A comparison across periods can be affected by time-related changes or differences in who is observed during each period. The registry does not describe a method for separating such influences from intervention effects. For that reason, these arms should not be read as a like-for-like randomized control comparison.

What do the planning assumptions mean?

The record describes planning illustrations using a two-sided significance level 0.05, equal allocation between arms, and a normal approximation. It also describes an effect to detect as a stated fraction of an observed effect. Such calculations are hypothetical design exercises: they ask what sample size might be needed under assumptions about an effect and analysis. They are not measurements of what happened in the completed study, and they are not observed power.

Power is a design property under an assumed effect, variability, significance level, and analysis. Calculating power after observing results does not establish that the study had a particular ability to detect an effect. Because no outcome effect or numerical planning result is reported in the trial details, the planning assumptions cannot be used to infer an observed effect, a sample-size justification, or a statistical conclusion about feasibility.

How should outcome timing be read?

The primary endpoint is assigned a 12-week timeframe. The arm descriptions instead schedule intervention during Weeks 1-8 for Group 1 and Weeks 9-16 for Group 2. The adverse-event group labels refer to Weeks 1-6 and Weeks 7-12. These are distinct time descriptions in the registry record. Without an explanation of their relationship, the timing cannot be harmonized or used to infer when each outcome was measured.

The secondary outcome is change in psychological flexibility from baseline to 6 weeks. Change outcomes generally compare a measurement at follow-up with a baseline measurement, but the record does not provide the numerical measurements, the calculated change, or the statistical procedure used. It is therefore not possible to assess the magnitude, variability, or uncertainty of that outcome.

These concepts describe how the listed measures could be interpreted. They do not establish which estimator, test, confidence-interval method, or missing-data procedure was used. The registry record does not report those methods.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 4 outcome measures, including the primary completion and retention endpoint and a secondary outcome of change in psychological flexibility from baseline to 6 weeks. It lists 0 analyses. Numerical results and the analysis procedures for these outcomes are not reported in the registry record. The identities and results of the other listed outcome measures are not included in the trial details recorded.

Multiplicity arises when several outcomes, time points, or comparisons are analyzed. Conducting multiple tests can increase the chance of at least one apparently notable result under a null hypothesis. A prespecified hierarchy or adjustment can address some multiplicity concerns, but the registry record does not report a multiplicity plan, a testing hierarchy, or an adjustment procedure. It is not possible to determine from the available record whether or how multiplicity was handled.

Missing-data methods are also not reported. The completion definition excludes participants who were unable to meet during the times sessions were held, while retention is defined for all enrolled participants. These are endpoint-specific denominator rules, not a general account of how missing outcome measurements were handled. The record does not state whether incomplete measurements were imputed, excluded, or addressed by another method.

The analysis populations are not described beyond the endpoint definitions: completion applies to participants able to attend 4+ sessions, and retention applies to all enrolled participants. The recorded enrollment is 30, but the registry does not report the number included in each outcome analysis or any departures from the stated populations. The record also does not report a statistical analysis plan. Therefore, interpretation should not assume a particular missing-data strategy, population definition, or multiplicity adjustment.

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.

The registry record contains adverse-event entries for Group 1 Intervention, Weeks 1-6, and Group 2 Intervention, Weeks 7-12. Each entry lists 15 participants at risk for serious adverse events and 0 participants affected. Each also lists 15 participants at risk for other adverse events and 0 affected, with 0 deaths in each entry. No serious adverse-event terms are listed.

These figures describe the recorded safety entries, not the primary feasibility outcome. A zero recorded count means that the registry reports no events in that category for the listed group and period. It does not prove that the intervention carries no risk, and it does not establish that events were actively sought or reported in a particular way; those details are not reported in the registry record.

The safety periods, Weeks 1-6 and Weeks 7-12, do not match the arm schedule described elsewhere as Weeks 1-8 and Weeks 9-16. The record does not explain the difference. The figures should therefore be read using their stated adverse-event labels rather than assumed to cover the full intervention schedule. They do not support conclusions about comparative safety because allocation was nonrandomized and the listed entries do not constitute a like-for-like control comparison.

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

The registry record describes a completed study intended to evaluate the feasibility and acceptability of a virtual Sister Circle protocol for middle- and older-aged Black women with depressive symptoms. It defines completion and retention as its primary feasibility measures and identifies psychological flexibility change from baseline to 6 weeks as a secondary outcome. These details clarify what the study set out to assess.

The record does not report the observed completion rate, retention rate, or psychological flexibility result. It also does not provide confidence intervals, p-values, or other outcome analyses. Without these results, it is not possible to judge the level of participation, the precision of a feasibility estimate, or the direction and size of change in the secondary outcome. The purpose and endpoint definitions alone do not establish that the intervention was feasible or acceptable.

The study is nonrandomized. The groups receive the intervention during different scheduled periods, with no treatment described for the other group during each period. This design can inform a feasibility evaluation, but a difference between groups or periods would not, by itself, isolate an intervention effect. The registry record does not report an adjusted comparison or explain how differences in group composition or timing were addressed.

The safety entries report 0 serious adverse events, 0 other adverse events, and 0 deaths for each listed group period. These are the recorded counts, not proof that no risk exists. The adverse-event periods also do not align with the arm schedule, and the record does not explain that discrepancy.

Accordingly, the defensible interpretation is limited to the study’s registered purpose, design, endpoint definitions, and recorded safety counts. It cannot establish a treatment effect, a symptom benefit, the acceptability of the intervention, or a definitive safety profile from the outcome information recorded in the registry.

13. Why This Trial Matters Statistically

Feasibility studies ask whether an intervention and its evaluation can be carried out, rather than relying only on clinical outcome comparisons. This registry record makes that distinction visible by naming completion and retention as the primary endpoint. Attendance and continued participation are operational outcomes: they can describe whether participants engage with a study under its particular scheduling and eligibility rules.

The two denominator definitions are statistically important. Completion is based on participants able to attend 4+ sessions, while retention is based on all enrolled participants. Clear denominator definitions prevent unlike quantities from being treated as the same rate. They also show why a percentage without its numerator, denominator, and inclusion rules can be difficult to interpret.

The study also illustrates how design affects inference. Nonrandomized allocation and intervention periods occurring at different times mean group comparisons do not have the same interpretation as a randomized, concurrent control comparison. Recognizing this is essential when distinguishing descriptive feasibility evidence from causal evidence about an intervention.

Finally, the registry record demonstrates the limits of interpreting a completed study when outcome results and analysis methods are not recorded. A completed status and an enrollment figure do not substitute for outcome estimates or uncertainty measures. The primary outcome definitions, secondary outcome listing, and safety counts can be described, but the missing outcome results prevent assessment of feasibility performance or the precision of any estimate.

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 contains limited information for interpreting outcomes. Although the study is marked completed and lists enrollment of 30, it does not report numerical primary or secondary outcome results, outcome counts, confidence intervals, p-values, or analysis procedures. This prevents assessment of the magnitude and precision of feasibility estimates and prevents reconstruction of the listed percentages.

The nonrandomized allocation limits causal interpretation of comparisons between groups. The arm descriptions place intervention and no-treatment periods at different times, and the registry record does not report how group differences, period effects, or other potential sources of bias were addressed. There is no reported adjusted comparative analysis.

There is an unresolved timing discrepancy. The arm descriptions identify intervention periods as Weeks 1-8 and Weeks 9-16, the primary endpoint timeframe is 12 weeks, and adverse-event entries are labeled Weeks 1-6 and Weeks 7-12. The record does not explain how these timeframes relate. The intervention schedule and the endpoint measurement window therefore cannot be fully reconciled.

The record does not specify an age range, detailed eligibility criteria, recruitment procedures, or the extent of follow-up. It also does not report a separate acceptability measure, the handling of missing outcome data, the analysis populations beyond the endpoint definitions, or a multiplicity plan. These omissions constrain interpretation of both feasibility and acceptability. The recorded safety counts are limited to the stated adverse-event entries and do not establish a complete safety profile.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Feasibility & Acceptability of a Virtual Sister Circle Intervention for Black Women With Depressive Symptoms — NCT04837573.
• Registry record last updated 2026-06-05; status last verified 2024-05.
• Results first posted 2026-06-05.
• 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

The registry record describes a completed, nonrandomized, parallel-model behavioral study of a virtual Sister Circle protocol for middle- and older-aged Black women with depressive symptoms. Enrollment is listed as 30. The study started on 2022-09-14, and primary completion is dated 2023-04-02.

The primary endpoint is completion and retention, with a 12-week timeframe. A secondary outcome is change in psychological flexibility from baseline to 6 weeks. The record lists 4 outcome measures and 0 analyses, but does not report numerical results for the primary or secondary outcomes.

The arm descriptions schedule the intervention in different periods for the two groups. Adverse-event labels use different periods, which the record does not reconcile. Each safety entry lists 0 serious adverse events, 0 other adverse events, and 0 deaths. These registry entries describe the registered design and recorded counts, but do not permit assessment of intervention effects or the precision of feasibility outcomes.