One-Day Acceptance and Commitment Training Intervention in Primary Care Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for One-Day Acceptance and Commitment Training Intervention in Primary Care Patients (NCT01879800), a randomized na study. The primary outcome is Mean Change in Participants World Health Organization Quality of Life Measure- Physical Score: Change From Baseline to 3 and 6 Month Follow-up..

2. Clinical Question

3. Trial Design

The study is registered as a randomized, single-masked, parallel-arm trial, with an enrollment of 44. The two arms are Treatment As Usual/Waitlist and Acceptance and Commitment Therapy plus Illness Management. The intervention description calls the workshop Acceptance and Commitment Training plus Illness Management (ACT-IM) and describes a one-day group format. The registry record does not identify who was masked or describe the randomization sequence, allocation concealment, or procedures used to assign participants.

The study’s stated aims were to examine the feasibility and acceptability of ACT-IM and to evaluate the intervention compared with TAU on mental health and functioning. The registry summary describes patients with vascular disease risk factors being identified, screened for depression or anxiety symptoms, and assessed. It says patients experiencing significant symptoms and interested in the treatment arm would be randomized. Specific diagnostic thresholds, eligibility criteria, and the details of the recruitment process are not reported in the registry record.

The primary outcome is change in the physical domain of the World Health Organization Quality of Life Measure, with follow-up at 3 and 6 months. The two listed secondary outcomes are changes in the Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale at those follow-ups. The record lists three outcome measures in total, but does not provide numerical results or explain how the multiple follow-up assessments were analyzed.

The registry status is COMPLETED. The record lists start and primary completion dates, but those dates do not by themselves establish when each participant completed follow-up or how complete follow-up was. Participant flow, withdrawals, adherence to the workshop, and use of other care are not reported in the registry record. The record identifies the sponsor as Lilian N. Dindo; a statistical analysis plan and details of the protocol are not reported.

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 Mean Change in Participants World Health Organization Quality of Life Measure- Physical Score: Change From Baseline to 3 and 6 Month Follow-up., measured over Change at 3 and 6- Month Follow-up.

The primary endpoint is mean change from baseline in the physical domain score of the World Health Organization Quality of Life Measure. The domain concerns physical aspects of quality of life, including activities of daily living, dependence on medicinal substances and medical aids, energy and fatigue, mobility, pain and discomfort, sleep and rest, and work capacity. The registry record specifies follow-up at 3 and 6 months.

Each item is scored from 1 to 5, with higher ratings representing more positive perceptions. The mean of the items in the physical domain is multiplied by 4 to form a domain score from 4 to 20. Higher domain scores indicate higher quality of life in physical ability. Because the endpoint is a continuous score, mean change describes the average direction and magnitude of change in the group; a between-arm comparison would address whether average change differed between ACT-IM and TAU.

Quality of life is included because the study’s stated goals extend beyond symptoms to functioning and physical health-related experience in people with mood or anxiety symptoms and vascular risk factors. A physical quality-of-life score can capture several aspects of daily experience in one measure. It does not, on its own, establish changes in vascular health, illness self-management, or mental health symptoms. The registry record defines the endpoint but does not report its observed mean changes, uncertainty, or between-arm estimate. It also does not report a threshold for interpreting a change as important to participants.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design is described as randomized, parallel, and single-masked. Randomization is intended to make treatment allocation independent of participants’ measured and unmeasured characteristics on average. It does not guarantee that the groups will be identical, particularly in a small trial. The registry record does not specify the random sequence method, concealment of assignment, or the identity of the masked party, so the protections used against allocation or assessment bias cannot be evaluated from this record.

What does a mean-change endpoint represent?

The primary outcome is continuous: it is a physical quality-of-life domain score, and the endpoint is change from baseline. A mean change summarizes the average within-group shift in scores across participants with available data. For a treatment comparison, a common target is the difference between the average changes in the two arms. That contrast is not the same as observing that one group changed from its own baseline: a within-group change can reflect many influences, including time, usual care, and measurement variation. The registry record does not report either arm’s mean change or the between-arm contrast.

The scale is oriented so that higher domain scores indicate higher physical quality of life. This direction helps interpret a reported score change, but the record contains no observed change to interpret. It also does not report a minimally important difference or another threshold for judging the practical importance of a change. Statistical evidence and practical importance are separate questions: an estimate can be statistically distinguishable from zero yet small in practical terms, or large but uncertain. The registry record does not permit either judgment for this endpoint.

What does standard error tell the reader?

The registry endpoint lists standard error as the dispersion measure. In general, standard error describes the uncertainty in an estimated mean, rather than the spread of individual participants’ scores. It tends to be smaller when a mean is estimated more precisely, but its interpretation depends on the analysis and the data used. It is not interchangeable with a standard deviation, which describes participant-level variation. No standard error values are reported for the primary outcome in the registry record, so the precision of the means cannot be assessed.

General statistical explanation: a confidence interval is constructed to represent uncertainty around an estimate under a statistical model and its assumptions. Its width depends on factors such as variability, sample size, and the analysis method. A confidence interval for a between-arm difference would show which effect sizes remain compatible with the data and model. No such interval is reported for the primary comparison. A p-value, if reported, would address compatibility with a null hypothesis under an analysis model; it would not measure the probability that the null hypothesis is true or quantify clinical importance. No p-value for the primary comparison is reported in the registry record.

How should the follow-up times be considered?

The primary endpoint is assessed at 3 and 6 months, and the secondary symptom measures are also specified at 3 and 6 months. Repeated measurements on the same participants are related, so a statistical analysis may need to account for within-participant correlation. General approaches can estimate time-specific contrasts or model outcome trajectories, but the appropriate approach depends on the prespecified question and assumptions. The registry record does not report the model, covariance structure, or whether measurements were analyzed separately or together. It is therefore not possible to identify the method used to account for repeated measures.

Multiple outcomes and time points create more than one opportunity to examine results. If many tests are considered without a plan, the chance of at least one apparently notable result can increase. An analysis plan may specify a primary contrast or a method to address multiplicity. The registry record names one primary outcome and two secondary outcomes, each with follow-up assessments, but does not report how multiplicity was handled. This does not imply that any particular adjustment was or was not performed.

What assumptions underlie planning calculations?

The registry record describes a planning illustration using a two-sided significance level of 0.05, equal allocation between arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. These are assumptions for a planning exercise, not evidence about the trial’s actual power. The record does not report the trial’s own sample-size justification or the effect estimate used for a numerical illustration in the registry record for this analysis.

General statistical explanation: sample-size planning asks how many participants would be needed under specified assumptions to detect a target effect with a chosen probability. It is not an estimate of the probability that a completed trial’s result is true. “Observed power,” calculated after looking at an estimated effect, adds little information beyond the estimate and its uncertainty. Planning counts based on a fraction of an observed effect are hypothetical scenarios, not additional trial findings. No planning count should be mistaken for the 44 participants enrolled.

Over-dispersion is a general issue when observed variability exceeds what a statistical model assumes. If present and ignored, standard errors may be too small and confidence intervals too narrow. The registry record does not identify a count outcome or a model involving over-dispersion for the primary endpoint; the endpoint is a continuous mean. No specific variance model or diagnostic assessment is reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary physical quality-of-life outcome and two secondary symptom outcomes: HAM-D and HAM-A. The outcome descriptions include assessments at 3 and 6 months. Considering more than one outcome and follow-up can create multiplicity: repeated testing can increase the chance of at least one result appearing unusual under a null model. A prespecified hierarchy, a defined primary contrast, or an adjustment can help clarify how such results should be interpreted. The multiplicity strategy is not reported in the registry record.

The record gives no numerical analysis results, and it does not report a statistical analysis plan, model specifications, covariate adjustments, or the particular contrast used for the primary endpoint. The number of analyses is listed as 0. This means no analyses are recorded in the available registry information; it does not establish whether analyses were conducted outside the registry or what conclusions they produced.

Missing-data handling is also not reported in the registry record. The record does not state the number of participants with completed primary outcome measurements at baseline or follow-up, reasons for missing assessments, or whether any imputation or other method was used. The analysis population—such as all randomized participants or participants with observed follow-up data—is not described. These details matter because missingness can affect both the size and interpretation of an estimated treatment contrast.

The overall enrollment of 44 cannot be assumed to equal the number included in every outcome analysis. Likewise, the adverse-event monitoring counts do not establish the available sample size for the quality-of-life or symptom analyses. Without outcome-specific denominators and a stated missing-data method, the completeness and potential impact of missing follow-up cannot be assessed.

11. Safety Results

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

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 lists zero serious adverse events in Treatment As Usual/Waitlist, with 14 participants at risk, and zero in Acceptance and Commitment Therapy Plus Illness Management, with 30 participants at risk. It also records zero other adverse events in each arm, using those same at-risk counts. These are the event counts recorded in the registry; they are not a comparison of the probability of harm with an uncertainty estimate.

The death counts are null in the record, so death results are not reported in the registry record. Zero recorded events should be read as a report of no events in the listed categories in the registry, not as proof that no events occurred or that an intervention is free of risk. The record does not give event definitions, monitoring procedures, observation periods for adverse events, severity beyond the serious/non-serious categories, or reasons participants may not have contributed safety information.

The at-risk counts describe the denominators recorded for these safety categories; they should not be substituted for outcome-specific analysis counts. The small overall enrollment and absence of event-level detail limit what can be concluded from the safety entries. In particular, these figures do not estimate rare risks precisely and do not support a safety comparison beyond the events recorded.

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

The registry record establishes that a randomized, parallel-arm study was completed with enrollment of 44 and that it was designed to compare a one-day ACT-IM workshop with Treatment As Usual/Waitlist. It identifies physical quality of life as the primary outcome and changes in depression and anxiety measures as secondary outcomes. It also records zero serious and zero other adverse events in the listed arms and provides the corresponding at-risk counts.

Those design and safety details do not answer whether average quality of life, depression, or anxiety changed differently between the groups. Numerical outcome estimates, confidence intervals, and statistical tests are not reported in the registry record. Thus, no direction or magnitude of benefit or harm can be attributed to ACT-IM from these entries, and the degree of precision of an outcome comparison is unknown. The absence of reported outcome results is not a finding of no effect.

The study’s aims included feasibility and acceptability, but the registry record does not report numerical measures of either. It also does not report participant adherence, outcome completion, or the results of the planned assessments of illness self-management, blood vessel health, and blood. The endpoint definitions indicate what the study intended to assess; they do not demonstrate that an effect was observed.

General interpretation: an effect estimate is most informative when read alongside its uncertainty, the outcome definition, follow-up time, and the analysis population. Clinical importance cannot be determined from statistical significance alone, and neither can be assessed without outcome results. The record does not provide enough information to compare the intervention’s effects across time or to determine whether any observed change was sustained.

Accordingly, the defensible conclusion is limited to the registered design, outcome definitions, enrollment, and recorded adverse-event counts. Claims about comparative effectiveness, symptom improvement, quality-of-life change, feasibility, acceptability, or safety beyond the recorded categories would require results and methods not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable because it brings together a randomized comparison, a brief behavioral group intervention, and a population described as having both vascular disease risk factors and significant depressive or anxiety symptoms. The study aimed to examine both feasibility and acceptability and outcomes related to mental health and functioning. Its primary endpoint is a continuous quality-of-life domain score, while the secondary outcomes focus on depression and anxiety symptoms.

For researchers, the endpoint structure highlights the need to distinguish change within each arm from the contrast between arms. A change from baseline can be observed in both groups; the comparative question concerns whether those changes differ. The two follow-up assessments also raise questions about how repeated measurements and multiple outcomes were handled. The statistical plan and numerical results are not reported in the registry record, so those questions remain open rather than answerable from the outcome definitions.

The safety entries illustrate another statistical point: event counts require context, including denominators, definitions, and observation periods. The record does include at-risk counts for each arm, but its zero counts alone cannot establish that the intervention has no safety risks or allow a precise risk comparison.

Finally, the enrollment count should not be confused with an analysis sample size or evidence of adequate power. Adequacy depends on the target effect, outcome variability, design, follow-up, and analysis assumptions. The record does not report the trial’s own sample-size justification or outcome analyses. This distinction matters when interpreting a completed small trial: without effect estimates and uncertainty, the record describes what was studied but does not quantify what the comparison found.

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.

A central limitation of the registry information is that it defines the primary and secondary outcomes without reporting their numerical results. There are no arm-specific outcome summaries, between-arm contrasts, confidence intervals, or tests recorded for the quality-of-life, depression, or anxiety outcomes. As a result, the comparative findings and their precision cannot be evaluated.

The outcome schedule includes assessments at 3 and 6 months, but the registry record does not describe the analysis used to account for repeated measures or specify the primary contrast across those times. It does not report multiplicity procedures, covariate adjustment, or model assumptions. The statistical analysis plan is not reported in the registry record.

Although the study is described as randomized and single-masked, the record does not identify the masked party or explain sequence generation or allocation concealment. Recruitment details are broad, and eligibility thresholds are not reported. The TAU/Waitlist description does not specify the care or waiting arrangements. These omissions limit assessment of potential selection, performance, and measurement biases.

Participant flow, follow-up completion, workshop attendance, and adherence are not reported. Neither outcome-specific denominators nor missing-data methods are available, so it is not possible to determine how missing observations may affect the results. The stated aims include feasibility and acceptability, but no corresponding findings are reported. Assessments mentioned in the summary, including illness self-management, blood vessel health, and blood, are not accompanied by outcome results in the registry record.

The safety information gives event counts and at-risk numbers, but not event definitions, timing, monitoring detail, or death counts. Zero recorded events therefore offer limited information about the occurrence or comparative risk of adverse events. These limitations are specific to what the registry record reports; additional protocol or results information is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: One-Day Acceptance and Commitment Training Intervention in Primary Care Patients — NCT01879800.
• Registry record last updated 2017-05-25; status last verified 2017-05.
• Results first posted 2015-08-28.
• 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

NCT01879800 is a completed randomized, single-masked, parallel-arm trial with enrollment of 44. It compares a one-day Acceptance and Commitment Training plus Illness Management group workshop with Treatment As Usual/Waitlist in patients described as having vascular disease risk factors and significant depressive or anxiety symptoms.

The primary outcome is mean change in the World Health Organization Quality of Life Measure—Physical score from baseline to 3 and 6 months. The listed secondary outcomes are changes in HAM-D and HAM-A at those follow-ups. Numerical results for these outcomes, the statistical analysis plan, missing-data methods, and analysis populations are not reported in the registry record.

The registry records zero serious and zero other adverse events in both arms, with 14 and 30 participants at risk, respectively. Death counts are not reported in the registry record. The record defines the study’s questions and measures, but does not report the comparative outcome estimates needed to determine their direction or precision.