Investigating Compassion-Based Guided Self-Help for Depression in People With Skin Conditions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Investigating Compassion-Based Guided Self-Help for Depression in People With Skin Conditions (NCT04132973), a na na study. The primary outcome is Acceptability of Intervention Overall.

2. Clinical Question

The study’s central question concerns acceptability and feasibility, rather than a controlled estimate of treatment effect. Retention was defined through online login during each participant’s sixth week; the study also sought explicit feedback about acceptability and explored whether online self-help and email guidance could be delivered.

Changes in depression, self-compassion and skin-related distress were also to be assessed after six weeks. These measures were intended to help estimate likely effect sizes for future research. The registry record identifies the Depression Anxiety Stress Scales depression subscale, the Self-Compassion Scale and the Dermatology Life Quality Index as secondary outcomes. It does not report their observed results.

With no control group, any observed change would describe participants over time in this study, not a contrast with what would have happened without the intervention. The registry record does not report a primary outcome count or percentage, so it does not establish the level of week-6 retention. The question that can be evaluated from the recorded design is therefore whether the study set out to measure engagement and feasibility, not whether the intervention caused a change in depression or skin-related distress.

3. Trial Design

This was a completed, single-group behavioral study sponsored by the University of Sheffield. The registry record lists enrollment as 34, masking as none, and allocation as NA. The study dates are 2019-11-12 to 2020-03-23 for start and primary completion, respectively. The registry status is completed.

Participants were to take part in the Compassion for Skin Conditions programme, an online compassion-based self-help intervention lasting six weeks, with email guidance from the researcher. The record describes people with heterogeneous skin conditions and depression as the focus. It does not report detailed eligibility criteria, baseline characteristics, the number who began the intervention, or the number who completed all study activities.

The primary outcome was an acceptability measure based on engagement: whether a participant logged in to the online intervention during their sixth week. Week 6 was defined for each participant, with rolling recruitment. This means the assessment point was tied to each person’s participation rather than to one common calendar date.

Secondary outcomes concerned change from baseline to after six weeks in depression, self-compassion and dermatology-related quality of life. The registry lists 10 outcome measures overall but does not give results for these measures in the record described. The number of analyses is recorded as 0; no analysis results or statistical plan are reported in the registry record.

Because there was no randomized allocation or control group, this design cannot provide a like-for-like comparison between people receiving the intervention and people receiving another condition. Its stated aims are acceptability, feasibility and preliminary estimation of likely effect sizes for later research. The registry record does not report a phase designation beyond NA, a sample-size justification, or an interim-analysis plan.

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 Acceptability of Intervention Overall, measured over Week 6 for each participant (rolling recruitment)..

The primary endpoint is titled “Acceptability of Intervention Overall.” It counts participants who logged in to the online intervention during their sixth week. The assessment was made at week 6 for each participant, with rolling recruitment. This operational definition treats continued login as an indicator of participant retention and engagement with the online programme.

Retention is useful in a feasibility study because it describes whether participants continue to access an intervention through the intended period. It can help researchers judge whether the delivery format and duration can be studied further. It is not itself a measure of depression improvement, self-compassion, skin-related distress, or satisfaction. The study also aimed to collect explicit feedback about acceptability, but the registry record does not report those feedback findings.

The registry record does not report the number or percentage of participants who logged in during week 6. Therefore the endpoint definition is available, but its observed result is not. Enrollment is recorded as 34, but that enrollment figure alone does not establish how many participants reached week 6 or logged in at that time. The registry record also does not describe how login data were handled if participants had incomplete or unavailable records.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the single-group design imply?

The registry identifies this as a single-group study. Participants took part in the intervention, and no concurrent control group is listed. In general, a single-group design can describe implementation and changes observed among participants over time. It cannot directly estimate how those participants’ outcomes compare with outcomes under a different intervention or no intervention. Without that comparison, changes can reflect factors beyond the intervention itself, including the passage of time or other experiences during follow-up.

The allocation entry is NA and masking is listed as none. These entries are consistent with the absence of a randomized comparison in this record. They do not reveal additional details about how participants were recruited or enrolled; those details are not reported in the registry record.

How should the primary endpoint be understood?

The primary outcome is a binary engagement measure at the participant level: whether a participant logged in during their sixth week. A binary outcome records whether a defined event occurred, rather than measuring a continuous score. For a group, it is often described using the number of participants with the event and the proportion or percentage of the group represented by that count. The registry record gives the outcome definition but not its observed event count or percentage.

General statistical context: a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis. A wide interval generally indicates less precision than a narrow interval. No interval for the primary outcome is reported in the registry record, so its precision cannot be assessed from this entry.

What do the secondary outcomes add?

The secondary outcomes concern change from baseline to after six weeks in DASS-DEP, the Self-Compassion Scale and the Dermatology Life Quality Index. These measures address different constructs: depression symptoms, self-compassion and skin-related quality of life. The fact that the outcomes are named does not establish that results were collected or analyzed. Their observed values, changes and uncertainty estimates are not reported in the registry record.

General statistical context: a change score is interpreted relative to the scale’s scoring and the direction in which scores indicate more or less of the construct. The record does not give score results or a statistical analysis plan, so no direction or magnitude of change can be interpreted for these measures.

What are the planning illustrations intended to show?

The sample-size assumptions describe planning illustrations based on an observed effect, not a design feature or observed power for this single-group study. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two hypothetical arms, a normal approximation, and an effect set to a stated fraction of the observed effect. For time-to-event calculations, the assumption describes total events; for other calculations, it describes participants per arm. These are hypothetical planning conventions and do not mean that this study had two arms.

General statistical context: a planning calculation estimates how much information a future study might need to detect a specified effect under stated assumptions. Its result depends on the assumed effect, variability, design and analysis. A planning illustration is not an observed finding, and it is not “observed power.” The registry record does not report the underlying effect estimates or values for these illustrations, nor does it report a sample-size justification for the current study.

Why does over-dispersion matter in some analyses?

General statistical context: for count outcomes, over-dispersion means the observed variation is greater than would be expected under a simple count model. If a model does not account for this extra variation, uncertainty can be understated and intervals or tests can be misleading. This concept is relevant only when the outcome and model call for it; the primary endpoint in this study is defined as participants who log in, not as a rate of repeated events. The registry record does not report a model or an analysis that would establish whether over-dispersion was considered.

More broadly, the registry record does not report methods for handling incomplete observations, defining analysis populations, adjusting for baseline values, or estimating uncertainty. These omissions limit methodological interpretation: an endpoint definition alone does not tell readers how observed data would be analyzed. The record lists 0 analyses, so no statistical result from which to evaluate those choices is available.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Compassion Guided Self-help")
n      <- c(34)
events <- c(11)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Compassion Guided Self-help  34  11  32.4  17.4  50.5  19.1  49.2  19.1  49.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures, including the primary acceptability endpoint and the secondary changes in depression, self-compassion and dermatology-related quality of life. It records 0 analyses and does not report outcome results. The record therefore does not show how many measures were analyzed, which results were emphasized, or whether any approach to multiple testing was planned.

General statistical context: when several outcomes are tested, the chance of at least one apparently unusual result can increase if each is assessed separately without accounting for multiplicity. The implications depend on the analysis plan and the role of each endpoint. A pre-specified primary outcome can help focus interpretation, but a title or listing alone does not establish how multiplicity was handled in analysis. The registry record does not report a multiplicity strategy.

Missing-data methods are also not reported in the registry record. It does not state how participants without a week-6 login record, incomplete questionnaires, or withdrawals were treated in the analyses. Nor does it report whether results used all enrolled participants, only participants who began the intervention, or another analysis population. The enrollment figure of 34 does not establish the denominator used for any endpoint.

These gaps matter because retention and missing observations are closely related in a feasibility study. Without participant flow and endpoint denominators, readers cannot distinguish non-engagement from unavailable outcome data. No imputation method, sensitivity analysis, or other missing-data procedure is described in the registry record. Interpretation should therefore remain limited to the recorded aims, endpoint definitions and descriptive safety counts.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists 34 participants at risk for serious adverse events and 0 with a serious adverse event. It lists 34 participants at risk for other adverse events and 3 with other adverse events. The deaths count is 0. No serious adverse event terms are listed.

These counts are descriptive safety information for the single intervention group. They do not provide a comparison with an untreated or alternative-treatment group, so they cannot estimate a relative difference in event risk. The record also does not provide event descriptions for the other adverse events, timing, severity details beyond the serious-versus-other categories, or information about how events were assessed.

General statistical context: a zero count in a study does not establish that an event cannot occur. The ability to characterize uncommon events depends on the amount of observation and the completeness of reporting. The registry record does not provide a detailed safety analysis or uncertainty estimates. The counts should be read as events recorded for this study, not as a comprehensive safety profile.

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

The record establishes that a six-week online compassion-based guided self-help intervention was studied in a single group of people with depression and skin conditions, with an emphasis on acceptability and feasibility. It defines retention as logging in during each participant’s sixth week and names secondary outcomes for depression, self-compassion and skin-related quality of life. It also records safety counts.

It does not report the observed primary endpoint count or percentage. It does not report results for the secondary outcome changes, participant feedback, or intervention feasibility. Consequently, the record cannot show how many participants remained engaged through week 6, what changes were observed, or how precisely any such changes were estimated.

The absence of a comparator is central to interpretation. This study cannot provide a controlled estimate of what would have happened under another condition. The registry entry therefore does not establish that the intervention caused improvement or caused no improvement. It also cannot support a direct comparative safety conclusion.

The study’s aim to estimate likely effect sizes for future research is distinct from confirming an effect. Early estimates can be useful for planning, but the registry record does not report the effect estimates or their uncertainty. The planning assumptions described for hypothetical two-arm calculations do not make the actual study randomized or comparative, and those illustrations are not observed power.

In short, this record is informative about the study’s intended question, delivery format, endpoint definitions and recorded adverse-event counts. It is not sufficient to judge the observed acceptability result, changes on the named scales, or clinical impact. Those results are not reported in the registry record.

14. Why This Trial Matters Statistically

Feasibility studies address practical questions that can determine whether a larger study is worth developing: can the intervention be delivered, will participants engage with it, and can the intended outcomes be measured? This study’s focus on online delivery, email guidance and week-6 login makes participant engagement a central design concern. Its stated intention to collect explicit feedback adds an acceptability dimension beyond login alone.

The statistical distinction between feasibility and effectiveness is important. Retention is a useful process outcome, but it is not a direct measure of depression or quality of life. Changes in clinical scales can help generate hypotheses and inform future planning, but a single-group study cannot distinguish an intervention-related effect from other explanations for change. The registry’s stated purpose of estimating likely effect sizes is therefore appropriately exploratory in scope.

Clear outcome definitions are valuable because they identify what a future study would need to measure. Here, the week-6 login definition provides a concrete operational measure of retention, while the named secondary outcomes identify domains for follow-up assessment. Yet definitions are not results. Without observed counts, change estimates, participant flow and uncertainty measures, readers cannot evaluate whether the feasibility targets were achieved.

The record also illustrates why transparent reporting matters: a completed status does not by itself communicate endpoint findings, analysis choices or missing-data handling. For statistical interpretation, those details are needed to assess the evidence and to plan subsequent work. The record offers a framework for understanding the study’s aims, but its reported results are too limited to quantify acceptability or outcome change.

15. Limitations

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

The principal limitation for interpretation is that the registry record does not report the observed primary endpoint result. Although retention is clearly defined as a week-6 login, the number of participants meeting that definition and the denominator used for the calculation are absent. The enrollment figure of 34 cannot fill this gap.

Results for the secondary outcomes are also not reported. The record names change in depression, self-compassion and dermatology-related quality of life as outcomes, but gives no baseline or follow-up values, change estimates, or uncertainty measures. Explicit participant feedback about acceptability is an aim, but its findings are not reported either.

The single-group design has no concurrent comparator, and masking is listed as none. Therefore any change observed over time would not be a controlled treatment contrast. This is especially important because the stated goal of estimating likely effect sizes may be misunderstood as a definitive efficacy analysis; the design and available reporting do not support that interpretation.

Participant flow, recruitment details, eligibility criteria, baseline characteristics, adherence beyond the primary login definition, and analysis populations are not reported in the registry record. Missing-data procedures, multiplicity handling, statistical models, confidence intervals and a sample-size justification are also not reported. The record lists 0 analyses, leaving no reported outcome analysis to assess.

Safety reporting is limited to counts: 0 serious adverse events, 3 other adverse events and 0 deaths, with 34 participants at risk in each adverse-event category. No serious event terms are listed, and detailed descriptions of the other events are not given. These limitations mean that neither efficacy nor a comprehensive safety profile can be inferred from the registry entry.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Investigating Compassion-Based Guided Self-Help for Depression in People With Skin Conditions — NCT04132973.
• Registry record last updated 2021-10-26; status last verified 2019-10.
• Results first posted 2021-10-26.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT04132973 is a completed, single-group behavioral study sponsored by the University of Sheffield. Enrollment is recorded as 34. Participants were assigned no listed comparator and took part in a six-week online compassion-based self-help programme with researcher email guidance. The study focused on acceptability and feasibility for people with depression and heterogeneous skin conditions.

The primary endpoint was week-6 login as a measure of retention. Secondary outcomes were changes in depression, self-compassion and dermatology-related quality of life. The registry record does not report the primary endpoint result, secondary outcome results, or participant feedback findings. It lists 0 serious adverse events, 3 other adverse events and 0 deaths. No controlled treatment-effect conclusion can be drawn from this single-group record.