Effectiveness of Propranolol For Treating People With Post-Traumatic Stress Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of Propranolol For Treating People With Post-Traumatic Stress Disorder (NCT00648375), a randomized phase 4 study. The primary outcome is Change in Severity of PTSD Symptoms Measured by Clinician Administered PTSD Scale for DSM-IV (CAPS-DX).

2. Clinical Question

3. Trial Design

The registry record classifies the study as a randomized, double-blind, parallel-group Phase 4 trial. It lists post-traumatic stress disorder as the condition and propranolol and placebo as the drug interventions. A cognitive therapy workbook is also listed, but how it was used, which participants received it, and whether it was intended to accompany either medication are not reported in the registry record.

The planned medication period was 14 weeks. In both arm descriptions, participants were to self-administer the assigned medication when acute hyperarousal symptoms occurred, with use limited to no more than twice per day. The record does not describe additional dosing instructions, adherence measures or changes to treatment during follow-up.

The registry record reports enrollment of 12 participants and a primary outcome population of 3 subjects who enrolled and completed all study visits. It does not explain the status or outcome data for the other enrolled participants. The outcome population therefore should not be assumed to represent everyone randomized or enrolled.

The study status is terminated. The record lists a start of 2003-12 and primary completion of 2009-06. It does not report why the trial was terminated or whether termination affected the planned analyses. No protocol-level sample-size justification, recruitment target rationale or planned interim analysis is 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.

Before assignment: 12 subjects were screened for the study. 3 subjects met enrollment criteria and were randomized to study medication.

Overall Study

Analysis population for the primary outcome, as defined in the registry: 3 subjects enrolled in the study and completed all study visits.

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.

Population: 3 of 12 subjects met inclusion criteria for the study

6. Primary Endpoint

The registry lists the primary outcome as Change in Severity of PTSD Symptoms Measured by Clinician Administered PTSD Scale for DSM-IV (CAPS-DX), measured over Measured at Week 0, 2,4,6,8,10,12,14.

The primary endpoint was change in PTSD symptom severity measured by the Clinician Administered PTSD Scale for DSM-IV (CAPS-DX). The registry describes the measure as a score on a scale, with scores ranging from 0-70 and higher scores representing more severe symptoms. It specifies a mean parameter and full-range dispersion, but does not report the numerical mean, range or change values.

Measurements were scheduled at Week 0, 2,4,6,8,10,12,14. Week 0 provides the listed starting measurement, followed by repeated assessments during the 14-week medication period. The record does not specify precisely how change was calculated, which visits were included in a single endpoint, or how repeated measurements were combined or compared.

In general, a symptom-severity measure can track whether scores move over time and can provide a common outcome for comparing treatment groups. A clinician-administered measure may also structure how symptoms are assessed. These are general reasons for using such measures; the registry record does not state why CAPS-DX was selected or give further information about its administration in this trial. No numerical primary endpoint result or arm comparison is reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a randomized, double-blind, parallel-group design. Randomization is intended, in general, to allocate participants to groups by chance, which can help balance measured and unmeasured characteristics on average. In a double-blind study, masking is intended to limit the influence of treatment knowledge on participant behavior, outcome assessment or other study processes. These are general explanations, not details of how this trial carried out randomization or masking; those procedures are not reported in the registry record.

What would an arm comparison estimate?

A treatment comparison usually needs an outcome summary for each arm and a clearly defined contrast between them. For this study, the primary outcome is CAPS-DX symptom severity measured at multiple visits. The record identifies a mean parameter, but gives no means, changes, arm-specific values or comparison estimate. It also states that the primary outcome has several categories or time points and was not reduced to one comparison. As a result, no single treatment-effect estimate can be interpreted from the registry record.

General statistical principle: a mean summarizes the center of a set of numerical observations. A range describes the lowest and highest values observed, while an uncertainty interval, when reported, addresses uncertainty in an estimated quantity. The registry specifies full-range dispersion, but does not give numerical values for the primary outcome. The listed score range of 0-70 describes the scale, not the distribution of observed scores in this trial.

Why do repeated measurements need a defined analysis?

Repeated assessments on the same participant are related rather than independent observations. A statistical method for repeated measurements generally needs to account for that within-participant relationship and define how the pattern over time will be summarized or compared. Possible approaches differ in their assumptions and in the question they answer. The registry record does not identify a repeated-measures model, a visit-specific comparison plan, a method for handling baseline scores, or a single summary time point. None should be inferred from the schedule alone.

General statistical principle: an analysis that treats correlated measurements as independent can misstate uncertainty. A method that accounts for correlation can use the repeated information while recognizing that measurements from one participant are connected. The appropriate method depends on the prespecified question, data structure and assumptions. Since the registry record lists zero analyses and does not report a statistical plan, it is not possible to determine which method, if any, was used for the posted outcome.

What would a p-value or confidence interval add?

General statistical principle: a p-value evaluates how compatible observed data are with a specified null model, under the assumptions of the test. It is not the probability that a treatment works, nor does it measure the size or clinical importance of an effect. A confidence interval gives a range of values compatible with the data and analysis at a stated confidence level; its width conveys precision. Neither a primary outcome p-value nor a confidence interval is reported in the registry record. Their absence prevents assessment of statistical uncertainty, but does not establish a null effect.

General statistical principle: small outcome samples tend to yield imprecise estimates, and a small observed sample can make estimates sensitive to individual observations. The primary outcome population includes 3 subjects who completed all visits. The record does not give arm-specific counts or individual scores, so the degree of sensitivity or precision cannot be quantified. It would be inappropriate to infer a treatment effect from the enrollment figure alone.

How should the planning illustrations be read?

The stated planning setup uses a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. It describes planning illustrations based on a stated fraction of the observed effect; time-to-event calculations, if applicable, are defined in terms of total events, while other calculations are defined as participants per arm. These are planning assumptions, not a report of the trial's original design justification. The registry record does not report a sample-size justification for the trial.

General statistical principle: a planning calculation depends on an assumed effect, variability, significance threshold, allocation and analysis method. Changing an assumption can change the required sample size. Any illustration based on an observed effect is hypothetical and depends on the stability and relevance of that observed estimate. It is not observed power, and it cannot replace the actual trial results. Because numerical primary outcome results are not reported, the planning illustrations cannot be treated as evidence about the size or certainty of an effect in this trial.

The registry record lists three secondary outcomes: change in depression measured by the Beck Depression Inventory (BDI), change in Post-traumatic Scale-Self Score (PS-SR), and change in Brief Symptoms Inventory-Short Form (BSI-SF). It reports four outcome measures overall, but does not provide numerical results for these secondary measures or identify an analysis plan for them. The distinction between a registered outcome and a reported result matters: listing an outcome does not establish that a result was analyzed or posted.

10. Multiplicity, Missing Data and Analysis Populations

The record identifies one primary outcome and three secondary outcomes: depression measured by BDI, post-traumatic symptoms measured by PS-SR, and symptoms measured by BSI-SF. The primary CAPS-DX outcome was scheduled at multiple visits. Considering several outcomes or time points can create multiplicity: in general, the more comparisons made, the greater the chance of at least one apparently notable result under a null model. Statistical plans may address this by defining a primary contrast or adjusting inference across comparisons. No multiplicity strategy, hierarchy of comparisons or adjustment method is reported in the registry record.

The record lists zero analyses. It does not give p-values or estimates for the primary or secondary outcomes, and it does not explain whether any analyses were conducted but not posted. Therefore, it is not possible to assess how multiplicity was handled in practice or to compare outcomes using reported estimates.

The primary outcome population is described as 3 subjects who enrolled and completed all study visits, while total enrollment is 12. The record does not describe the disposition of the other enrolled participants, specify missing outcome values, or report a method for handling missing data. It is therefore not appropriate to label the difference as a particular type of loss or to assume why participants did not complete all visits.

The analysis population is not identified as intention-to-treat, per-protocol or another defined group. The description of 3 completers identifies the reported primary outcome population, but does not say whether this was the planned analysis population. Randomized group counts and arm-specific outcome denominators are not reported in the registry record.

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 5% reporting threshold.

For the propranolol group, the registry record lists 1 participant at risk for serious adverse events and 0 affected. For the placebo group, it lists 2 participants at risk and 0 affected. The record lists no serious adverse event terms. Deaths are recorded as 0 in each group.

For other, non-serious adverse events, the record lists 1 participant at risk in the propranolol group and 2 in the placebo group, with 0 affected in each group. These counts should be read as the posted group figures, not as estimates of event rates in a larger population. The denominators are small, and no statistical comparison or uncertainty interval is reported.

General statistical principle: an absence of recorded events in a small group does not establish that an event cannot occur or that the groups have equivalent safety. The registry record does not describe the safety observation period, event collection procedures or the reason the recorded at-risk groups are small. The counts therefore describe what was recorded, but provide limited information about comparative safety.

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

The registry record establishes that a randomized, double-blind, parallel-group study of propranolol and placebo for post-traumatic stress disorder was registered and later marked terminated. It describes a 14-week medication schedule and repeated CAPS-DX assessments. It also identifies a primary outcome population of 3 participants who completed all study visits and reports the group-level safety counts.

It does not establish whether CAPS-DX scores improved, worsened or remained similar, either within an arm or between arms. Numerical primary outcome results, secondary outcome results, confidence intervals and p-values are not reported in the registry record. The record's listing of outcomes and measurement times should not be mistaken for evidence of a treatment effect.

General statistical principle: a trial result is interpreted through both its estimated effect and the uncertainty around that estimate. Without outcome estimates and uncertainty measures, readers cannot determine how large an observed difference might be or how precisely it was estimated. Nor can the lack of posted statistical results be taken as evidence of no difference, equivalence or absence of an analysis outside the registry.

The recorded safety counts show zero affected participants for serious and other adverse events in the listed groups, and zero deaths. Because only 1 and 2 participants, respectively, are listed at risk in the groups, these counts do not support a precise comparative safety conclusion. They are descriptive registry figures, not proof that adverse events could not occur.

The most defensible reading is therefore bounded: the registry record documents a study design, an outcome schedule, a small reported completer population and sparse safety counts, but does not provide results sufficient to quantify the effect of propranolol relative to placebo. This interpretation concerns the information reported in the registry, not a conclusion about what analyses may have been conducted elsewhere.

13. Why This Trial Matters Statistically

This trial illustrates why a registry entry needs to be read as a record of both study design and reporting status. The record identifies randomization, double masking, parallel groups, an active medication arm, a placebo arm and a repeated symptom measure. Those details help define the intended comparison, but they cannot answer the comparison without numerical outcome results.

The distinction between enrollment and the primary outcome population is important. The record reports 12 enrolled participants but identifies 3 completers as the population for the primary outcome. Without a disposition account, arm-specific counts or an analysis population definition, readers cannot tell how representative the completer results would be of the enrolled participants even if results were available.

The repeated CAPS-DX schedule also highlights the importance of specifying a primary contrast. In general, several time points can support different questions about symptom change. A single prespecified comparison, a time-course analysis and separate visit-level tests need not yield the same interpretation. The registry record does not report which approach was planned or used, and lists zero analyses.

There is also a useful distinction between planning and evidence. A sample-size illustration based on an assumed fraction of an observed effect describes hypothetical planning under stated assumptions; it is not the trial's observed power and does not supply missing outcome results. This matters especially when the posted primary outcome population is small and the record gives no effect estimate or precision measure.

For biostatisticians and clinical researchers, the central statistical lesson is that registration detail, outcome availability and inferential evidence are separate. A registered design can define what was intended, but only reported analysis results can quantify the comparison. Here, the registry record supports description of the intended trial and its reporting gaps, not a numerical efficacy conclusion.

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 principal limitation for interpreting this trial is that numerical primary and secondary outcome results are not reported in the registry record. Although four outcome measures are listed, the record lists zero analyses. There is no reported arm-specific CAPS-DX summary, treatment contrast, uncertainty interval or p-value from which to assess effect size or precision.

The primary outcome population is described as 3 subjects who completed all study visits, compared with total enrollment of 12. Participant disposition, randomized arm counts and the outcome data available for those who did not complete all visits are not reported. This prevents assessment of the amount and pattern of missing outcome information or whether the reported population aligns with a planned analysis population.

The outcome schedule includes multiple measurements, but the record does not specify how change was calculated or how the repeated assessments were analyzed. It does not identify a primary time-point contrast, repeated-measures model, missing-data method or approach to multiplicity. These are material uncertainties for interpreting a longitudinal outcome.

The role of the cognitive therapy workbook is also unclear. It is listed among interventions, but the arm descriptions do not explain its allocation or use. The record does not report why the study was terminated, how termination affected completion, or a sample-size justification. The small safety denominators and absence of detail about safety observation further limit interpretation of the adverse event counts. These limitations concern what the registry record reports and do not establish what may have been documented elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effectiveness of Propranolol For Treating People With Post-Traumatic Stress Disorder — NCT00648375.
• Registry record last updated 2020-01-02; status last verified 2019-12.
• Results first posted 2020-01-02.
• 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 Phase 4, randomized, double-blind, parallel-group trial of propranolol versus placebo for post-traumatic stress disorder. The medication schedule was 14 weeks, with self-administration at acute hyperarousal symptom onset, limited to no more than twice per day. A cognitive therapy workbook is listed, but its role is not described in the arm descriptions.

The primary outcome was change in CAPS-DX symptom severity, scheduled at Week 0, 2,4,6,8,10,12,14. The record reports 12 enrolled participants and identifies 3 subjects who completed all study visits as the primary outcome population. It lists three secondary outcomes and four outcome measures overall, but lists zero analyses. Numerical outcome results and the reason for termination are not reported in the registry record.

Serious and other adverse event counts are recorded as zero affected in each group, with 1 participant at risk in the propranolol group and 2 in the placebo group; deaths are recorded as zero in both groups. These small denominators and the absence of outcome analyses limit statistical interpretation.