Developing and Testing the Enhancing Active Caregiver Training (EnACT) Intervention for Dementia Family Caregivers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Developing and Testing the Enhancing Active Caregiver Training (EnACT) Intervention for Dementia Family Caregivers (NCT04920006), a randomized na study. The primary outcome is Imagined Interactions: Specificity.

2. Clinical Question

The study’s broader stated purpose is to develop and initially test EnACT with family caregivers. Its description says the work includes refining the intervention through small-group meetings and testing how achievable and useful caregivers find it. It also describes evaluating caregiver preparation, stress process, and well-being. These aims provide context for the primary measure, but they do not establish what the intervention changed: no outcome estimates for specificity, stress, burden, or positive aspects of caregiving are reported in the registry record.

The registry lists 30 participants enrolled and identifies the study as completed. Those details describe the trial record, not the number contributing data at every assessment. The record specifically notes a withdrawal after T2 and fewer Waitlist Control responses at that assessment. Without outcome estimates, uncertainty measures, and a clearly reported analysis, the primary question cannot be answered from the posted results.

3. Trial Design

The registry describes a randomized, unmasked, crossover study with a total enrollment of 30. It names two groups: Immediate Intervention and Waitlist Control. The study intervention is behavioral and is called Enhancing Active Caregiver Training. The registry lists the study as completed, with a primary completion date of 2024-12-31.

The Immediate Intervention description says participants first take part in three meetings, offered every two weeks at Weeks 2, 4, and 6, and then have eight weeks of follow-up. The primary measure’s schedule includes six assessments: baseline (T1), Week 2 (T2), Week 5 (T3), Week 8 (T4), Week 11 (T5), and Week 14 (T6). The registry identifies a crossover model, but the available group descriptions do not give a complete account of the sequence for both groups or the periods in which each group receives the intervention. Those details are not reported in the registry record.

Random assignment can help make groups comparable at the start of a trial, while a waitlist design can distinguish change over time from change during a period without the intervention. In a crossover design, participants may contribute observations under more than one condition; interpretation then depends on the treatment sequence, timing, and analysis of repeated observations. Those design details matter, but the full crossover schedule and its statistical handling are not reported in the registry record. Masking is listed as none, so the record does not describe participants or study personnel as masked to group assignment.

The registry states that the project first develops and refines EnACT with small-group meetings and then tests it with two groups of caregivers. It does not report further detail on the development phase, allocation procedure, or the precise analysis population. Enrollment and completion status alone do not show how many participants contributed to each primary outcome assessment.

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.

Before assignment: Following enrollment, each participant completed the baseline survey and completed a technology check to make sure they could access the intervention. No significant events occurred between enrollment and assignment to intervention or wait-list control groups.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: One participant withdrew from the study following T2, which is why the Waitlist Control reports 14 responses following Week 2 (T2).

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 Imagined Interactions: Specificity, measured over Assessed at six timepoints: baseline (T1), week 2 (T2), week 5 (T3), week 8 (T4), week 11 (T5), and week 14 (T6).

The primary endpoint is Imagined Interactions: Specificity, reported as scores on a scale. The Survey of Imagined Interactions measures outcomes of imagining interactions to prepare for the future; its Specificity subscale measures the level of detail within those imagined interactions. The subscale has four items, each using a 7-point Likert scale. The total score ranges from 4, representing less specificity, to 28, representing more specificity.

This measure is used to assess one aspect of caregiver preparation: how detailed imagined interactions are. It is not a direct measure of caregiver stress, burden, or well-being, although the registry describes those as broader areas of interest. The registry specifies the mean as the summary measure and standard deviation as the dispersion measure. Measurements are listed at baseline (T1), Week 2 (T2), Week 5 (T3), Week 8 (T4), Week 11 (T5), and Week 14 (T6).

Repeated assessments can describe how scores vary over the study schedule, but interpreting a treatment effect requires a defined comparison and reported outcome estimates. The registry does not report primary outcome means, standard deviations, confidence intervals, or a statistical test result. It therefore does not establish the direction, size, or precision of any change in specificity.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies Imagined Interactions: Specificity as a continuous outcome summarized by a mean and standard deviation. General statistical explanation: a continuous measure can take a range of numerical values, and a group mean gives its average while the standard deviation describes how spread out individual scores are around that average. For this endpoint, scores are totals across four items, with a stated range from 4 to 28. The registry does not report the group means or standard deviations at any timepoint.

Why do repeated assessments matter?

The primary outcome is scheduled at baseline (T1), Week 2 (T2), Week 5 (T3), Week 8 (T4), Week 11 (T5), and Week 14 (T6). Repeated measures can show whether outcomes change across time and whether patterns differ between groups. General statistical explanation: measurements from the same participant are usually related, so an analysis should account for that dependence rather than treating every observation as unrelated. A crossover design also requires attention to the sequence in which participants receive conditions and to the timing of measurements. The registry does not report the model, covariance structure, period effects, or other details used to analyze repeated observations.

A single endpoint comparison could focus on a prespecified assessment, a change from baseline, an average over assessments, or a model-based contrast. These approaches answer different questions. The record does not report which contrast was intended as the primary inferential comparison. Its note that the outcome has several timepoints and is not reduced to one comparison means there is no single posted estimate to interpret as the primary effect.

What does a confidence interval add?

General statistical explanation: a confidence interval communicates uncertainty around an estimated effect. A narrow interval indicates greater precision under the chosen method; a wide interval indicates less precision. The interval should be interpreted together with the effect estimate and the outcome’s scale. No confidence interval or effect estimate for Imagined Interactions: Specificity is reported in the registry record, so precision cannot be assessed.

A p-value, when reported, describes how compatible the observed data are with a specified null hypothesis under an analysis model. It does not measure the size or importance of an effect. The registry does not report a p-value for the primary endpoint. Even if one were available, it would need to be read alongside the estimate, its uncertainty, and the planned comparison rather than treated as a complete summary.

Why can over-dispersion matter?

General statistical explanation: over-dispersion arises when observed variation exceeds what a model assumes. If an analysis does not account for that extra variability, its standard errors may be too small and its intervals or tests may overstate precision. This issue is most directly relevant to count outcomes and particular model families; the primary endpoint is a continuous scale score. The registry does not identify an analysis model or report a diagnostic assessment, so there is no basis to say whether over-dispersion was relevant to any analysis in this study.

The registry’s planning illustration is described as using the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a specified fraction of the observed effect. These are planning assumptions, not evidence about the achieved precision of this trial. The planning illustration is not observed power, and no numerical planning results are reported in the record. The record also does not report the trial’s own sample-size justification, so the basis for enrolling 30 cannot be inferred from the planning illustration.

General statistical explanation: power is a design-stage probability tied to a specified effect, variability, sample size, and analysis. A retrospective calculation using an observed effect does not establish whether the trial was adequately designed, and it should not be used to reinterpret an unreported result. The registry’s stated planning method does not resolve the absence of primary outcome estimates.

The trial is labeled crossover, but the registry does not provide enough detail to reconstruct treatment sequences or the statistical model. In crossover studies, within-participant comparisons can be informative, while period and sequence effects may also matter. The precise validity of a crossover analysis depends on the design and assumptions. Those assumptions and any checks for them are not reported in the registry record.

Finally, statistical significance and practical importance are distinct. General statistical explanation: an estimate can be statistically distinguishable from a null value yet small in magnitude, or sizable but uncertain. Interpreting importance for this scale would require a reported effect and appropriate context for its meaning. Neither a threshold for meaningful change nor a primary outcome estimate is reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and 12 analyses. Secondary outcomes include Perceived Stress, Modified Caregiver Burden Inventory, and Positive Aspects of Caregiving Scale. The primary outcome is assessed at six timepoints. Considering multiple outcomes, timepoints, or contrasts can create multiplicity: when many statistical comparisons are made, the chance of at least one apparently notable result may increase. General statistical explanation: prespecifying a primary comparison and an appropriate multiplicity strategy can help readers distinguish confirmatory findings from exploratory patterns.

The registry does not report whether multiplicity adjustments were used, how outcomes were prioritized, or whether any analyses were designated exploratory. The record also does not report an analysis plan that clarifies how results across the primary outcome’s timepoints were to be combined or compared. As a result, the intended inferential role of individual tests cannot be assessed.

For missing data, the record notes that one participant withdrew following T2 and that the Waitlist Control group reports 14 responses following Week 2 (T2). This is the specific missing-response detail reported for the primary measure. It does not establish whether the other participants provided data at every assessment, whether data were missing for other reasons, or whether the withdrawal affected later outcome counts. The registry does not report a missing-data method, assumptions about missingness, or sensitivity analyses.

The analysis population is also not reported in the registry record. It is not stated whether analyses included all randomized participants, only participants with observed measurements, or another defined group. The crossover sequence and the way repeated observations were handled in the analysis are not reported either. Without those details, readers cannot assess whether the reported sample at each comparison would match the randomized groups or how missing measurements influenced estimates. Since outcome estimates themselves are not reported, no assessment of the consequences of multiplicity or missing data is possible.

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 lists 15 participants at risk for serious adverse events in the Immediate Intervention group and 15 in the Waitlist Control group. It reports zero serious adverse events in each group, zero other adverse events in each group, and zero deaths in each group. No serious adverse event terms are listed.

These figures describe what is recorded in the adverse-event summary; they do not show that every participant was assessed in the same way or for the same duration. The registry does not report detailed adverse-event definitions, collection procedures, attribution to the intervention, or the period covered by the safety summary. It also does not provide event-level narratives.

General statistical explanation: when no events are recorded, the observed count is zero, but that alone does not establish that an event is impossible or that an intervention is free of risk. The ability to estimate uncommon harms depends on the amount and duration of observation, among other factors. The registry’s safety counts should therefore be read as reported counts, not as proof of absence of risk.

The record gives the same at-risk count for both groups and reports no serious or other adverse events and no deaths. It does not report a comparative statistical analysis of safety outcomes. These counts should not be interpreted as evidence for a difference between groups or as a complete account of safety beyond the registry’s reporting.

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

The registry describes a randomized study of EnACT for family caregivers of persons living with dementia, with a primary outcome focused on the specificity of imagined interactions. It records a continuous scale measure, its range, the assessment schedule, group labels, and an enrollment of 30. It also records a withdrawal following T2 and the associated 14 Waitlist Control responses at that assessment.

Those details explain what the study was designed to examine, but they do not show the outcome. No primary means, standard deviations, treatment contrasts, confidence intervals, or p-values are reported. It is therefore not possible to determine from the registry whether scores changed, whether groups differed, or how uncertain any estimate was. The same limitation applies to the listed secondary outcomes of perceived stress, caregiver burden, and positive aspects of caregiving.

The stated aim includes development and initial testing, including whether caregivers find the intervention achievable and useful. The registry does not report numerical findings for those aims. It also does not provide enough detail to judge how the crossover design was implemented or analyzed. The safety summary records no serious adverse events, other adverse events, or deaths in either group, but the event counts do not establish that risks are absent.

General statistical explanation: an absence of posted estimates must not be mistaken for a finding of no difference. A null result would require reported data and an analysis capable of estimating the relevant contrast. Likewise, enrollment and completed status do not provide an estimate of effect or its precision.

The defensible interpretation is limited to the trial’s stated design, measurement plan, response-count note, and registry safety counts. Any claim about the size, direction, statistical significance, or practical importance of an intervention effect would go beyond what is reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it combines a randomized waitlist-control description with a crossover model and repeated measurement of a caregiver-focused outcome. That combination can support questions about change over time and differences associated with intervention timing, but only if the sequence, timing, and analysis are clearly reported. The registry does not provide enough detail to identify the specific crossover contrasts or their assumptions.

The primary measure also makes the analysis question important. Imagined Interactions: Specificity is assessed at baseline (T1), Week 2 (T2), Week 5 (T3), Week 8 (T4), Week 11 (T5), and Week 14 (T6). A trajectory across these assessments can tell a different story from a comparison at one timepoint. The registry’s note that the primary outcome has several timepoints and is not reduced to one comparison underscores why readers need an explicit estimand: the precise outcome contrast the study intends to estimate.

The record also highlights ordinary but consequential issues in small studies: response counts may vary over time, several outcomes are listed, and reported safety counts need a defined observation context. One withdrawal following T2 and 14 Waitlist Control responses at that assessment make transparent reporting of missingness and analysis populations particularly relevant. The registry does not report how those issues were handled.

For biostatistical interpretation, the key lesson is that design labels and outcome schedules are not substitutes for estimates. Means, measures of uncertainty, analysis definitions, and missing-data methods are needed to evaluate what the study found. Their absence in the registry limits quantitative conclusions, regardless of the study’s completed status or stated goals.

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 most important limitation for interpreting the posted record is that it does not report primary or secondary outcome estimates. The primary outcome is defined in detail, but its means, standard deviations, treatment contrasts, confidence intervals, and p-values are not reported in the registry record. The direction, size, and precision of any outcome difference therefore remain unknown.

The registry labels the study randomized, unmasked, and crossover, and describes Immediate Intervention and Waitlist Control groups. However, the available group descriptions do not fully specify both groups’ treatment sequences. The precise crossover schedule, period structure, allocation procedure, and statistical model are not reported. This prevents readers from reconstructing the intended comparison or assessing whether the analysis accounted for repeated measurements and crossover-specific considerations.

The primary outcome is assessed at six timepoints, but the registry does not identify one primary contrast across them. It also does not report a multiplicity strategy despite listing 12 outcome measures and 12 analyses. The analysis population, missing-data method, and sensitivity analyses are not reported. The stated withdrawal after T2 and 14 Waitlist Control responses at that assessment provide only a limited view of missingness.

Participant characteristics and further eligibility criteria are not reported in the registry record, limiting assessment of who the findings might represent even if estimates were available. The intervention’s detailed content and implementation information are also not reported. Finally, the safety summary lists zero serious events, zero other events, and zero deaths in both groups but does not specify the collection period or procedures. These record-specific limitations prevent a full evaluation of outcome interpretation, generalizability, and safety reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Developing and Testing the Enhancing Active Caregiver Training (EnACT) Intervention for Dementia Family Caregivers — NCT04920006.
• Registry record last updated 2026-05-20; status last verified 2026-04.
• Results first posted 2026-05-20.
• 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 identifies NCT04920006 as a completed randomized, unmasked crossover study of Enhancing Active Caregiver Training for dementia family caregivers. It lists 30 participants enrolled and names Immediate Intervention and Waitlist Control groups. The intervention description specifies three meetings at Weeks 2, 4, and 6 for the Immediate Intervention group, followed by eight weeks of follow-up.

The primary outcome is Imagined Interactions: Specificity, a mean score on a four-item scale with a range from 4 to 28. It is scheduled at baseline (T1), Week 2 (T2), Week 5 (T3), Week 8 (T4), Week 11 (T5), and Week 14 (T6). The registry notes one withdrawal following T2 and 14 Waitlist Control responses at that assessment. It lists Perceived Stress, Modified Caregiver Burden Inventory, and Positive Aspects of Caregiving Scale as secondary outcomes.

Safety reporting lists zero serious adverse events, zero other adverse events, and zero deaths in both groups. Outcome estimates, analysis methods, and missing-data procedures are not reported in the registry record.