This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Integrated Alcohol Disorder and PTSD Treatment (NCT01601067), a randomized phase 2 study. The primary outcome is Clinician Administered PTSD Scale (CAPS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01601067 |
| Phase | Phase 2 |
| Condition | PTSD, Alcoholism |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 168 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerns people with comorbid posttraumatic stress disorder (PTSD) and alcohol use disorder. The registry lists PTSD and alcoholism as conditions. It does not report further eligibility details or describe the characteristics of the enrolled participants in the registry record for this analysis.
Intervention
The intervention was Integrated Prolonged Exposure Therapy. The arm description identifies integrated prolonged exposure psychotherapy as prolonged exposure combined with elements of Integrated Cognitive Behavioral Therapy for alcohol use disorder. The intervention is classified as behavioral.
Comparator
The comparator was Seeking Safety, also classified as behavioral. The registry describes Seeking Safety as the comparison treatment and frames it as an integrated coping-skills psychotherapy. The record does not report treatment dose, session schedule, or adherence information in the registry record for this analysis.
Primary question
The primary question is whether the two treatment approaches differ in PTSD symptoms, measured with the Clinician Administered PTSD Scale (CAPS-5) from baseline through 6 month follow-up. The registry summary states the hypothesis that exposure therapy would allow participants to better sustain reductions in PTSD symptoms and alcohol use. That is the study's stated hypothesis, not a finding. The registry record does not reduce the primary outcome, which has several categories or time points, to one comparison. Therefore, the registry entries do not establish the size, direction, or precision of a single treatment contrast.
3. Trial Design
This was a phase 2, randomized, single-masked, parallel-group trial. The registry reports enrollment of 168 and a status of completed. The study start date is 2013-01-21, and primary completion is dated 2018-03-30. These registry entries describe the trial's design and timing; they do not indicate how many participants contributed data to any particular outcome analysis.
Participants were assigned to Integrated Prolonged Exposure Therapy or Seeking Safety. The former combined prolonged exposure with elements of Integrated Cognitive Behavioral Therapy for alcohol use disorder, while Seeking Safety served as the comparison intervention. Both are classified as behavioral interventions. The registry does not describe the masking procedure or identify which people involved in the trial were masked. It also does not report the sequence-generation or allocation-concealment procedures in the registry record for this analysis.
The primary outcome was CAPS-5 score, with the stated timeframe spanning baseline through 6 month follow-up. Timeline Follow-Back Procedure (TLFB) for Alcohol Use is listed as a secondary outcome. Although the registry identifies these outcome areas, it does not specify in the registry record how repeated assessments were modeled, which follow-up visit was used for each contrast, or how missing assessments were handled.
The registry summary explains the clinical motivation: comorbid alcohol use disorder and PTSD are common, and the study compared an exposure-based integrated approach with an integrated coping-skills approach. The summary's proposed benefit of exposure therapy is a hypothesis. The registry record does not report enough numerical primary-outcome information in the registry record to assess that hypothesis from a single contrast.
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: Enrolled participants were excluded from the study for the following reasons: 27 did not meet inclusion criteria; 15 did not complete intake or did not return for intake following informed consent;5 refused research after consent; 2 had travel or logistical constrains.
Overall Study
| Stage | Arm 1: Integrated Prolonged Exposure Therapy | Arm 2: Seeking Safety |
|---|---|---|
| STARTED | 63 | 56 |
| COMPLETED | 30 | 34 |
| NOT COMPLETED | 33 | 22 |
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.
| Characteristic | Unit | Arm 1: Integrated Prolonged Exposure Therapy | Arm 2: Seeking Safety | Total |
|---|---|---|---|---|
| Participants analysed | 63 | 56 | 119 | |
| Age, Continuous | years | 43.2 (SD 13.5) | 39.7 (SD 11.3) | 41.6 (SD 12.6) |
| Sex: Female, Male: Female | Participants | 7 | 5 | 12 |
| Sex: Female, Male: Male | Participants | 56 | 51 | 107 |
| Race/Ethnicity, Customized: White | Participants | 41 | 37 | 78 |
| Race/Ethnicity, Customized: Black | Participants | 8 | 8 | 16 |
| Race/Ethnicity, Customized: Asian | Participants | 3 | 3 | 6 |
| Race/Ethnicity, Customized: Other | Participants | 11 | 7 | 18 |
| Race/Ethnicity, Customized: Unavailable | Participants | 0 | 1 | 1 |
| Region of Enrollment: United States | Participants | 63 | 56 | 119 |
6. Primary Endpoint
The registry lists the primary outcome as Clinician Administered PTSD Scale (CAPS), measured over baseline through 6 month follow-up.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the Clinician Administered PTSD Scale (CAPS), described as the CAPS-5. It is a structured interview used to assess PTSD symptoms and diagnosis. The registry describes it as a 30-item interview and identifies it as the criterion standard for PTSD. Its stated score range is 0-80, with 0 indicating no PTSD symptoms and 80 indicating extreme ratings across all symptoms. Diagnosis was determined using a severity score of 2 or higher, following DSM-5 PTSD criteria.
A symptom score and a diagnostic classification are related but not identical kinds of information. A score can represent symptom severity across the measure, while a diagnostic rule classifies whether criteria are met under the stated threshold. The primary measure is described as a score on a scale, summarized as a mean with a 95% confidence interval. The registry timeframe is baseline through 6 month follow-up.
As a general statistical point, a mean can provide a concise summary of a continuous outcome, while a confidence interval communicates uncertainty around an estimated mean or contrast. The interval's width is relevant to precision; it does not by itself establish clinical importance. Numerical CAPS-5 estimates and confidence interval limits are not reported in the registry record for this analysis. The record also does not provide a single reduced comparison across the primary outcome's several categories or time points, so the primary endpoint cannot be interpreted as one quantified treatment effect.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The trial addresses an important statistical distinction: a stated hypothesis is not a result. The registry summary predicts that exposure-based integrated treatment would better sustain improvements in PTSD symptoms and alcohol use. The registry entries describe the design and outcome definitions but do not give a single numerical comparison for the CAPS-5 primary outcome. The registry record indicates that the primary outcome has several categories or time points and was not reduced to one comparison. Consequently, these registry entries do not establish whether the treatment groups differed, how large any difference was, or how precisely it was estimated.
The CAPS-5 is a continuous symptom measure in the registry's primary-outcome description, and the stated summary is a mean with a 95% confidence interval. In general, a confidence interval helps show the range of values compatible with an estimate under the analysis assumptions. A narrow interval generally indicates more precision than a wide one, but neither precision nor statistical significance alone determines whether an effect is important to patients. No numerical CAPS-5 means, treatment contrast, interval limits, or p-value are reported in the registry record for this analysis. Those quantities cannot be reconstructed from the enrollment figure or outcome description.
The registry also lists TLFB for Alcohol Use as a secondary outcome. The study summary links the treatment rationale to alcohol use as well as PTSD symptoms, but the registry entries available do not provide a numerical TLFB result. It is therefore not possible to characterize an alcohol-use difference or connect it quantitatively to the CAPS-5 outcome.
Safety information should be read separately from efficacy outcomes. The registry lists serious adverse events in the intervention arms and reports deaths and other adverse events separately. Those counts describe the posted safety record; they do not substitute for a comparative analysis of symptom change. Small event counts also tend to provide limited precision, and the registry information available does not include a formal safety comparison or detailed event-level context.
The trial's randomized, parallel design is relevant because random assignment is intended to support fair comparison of groups. However, interpretation also depends on details such as analysis populations, follow-up completeness, and the statistical model. Those details are not reported in the registry record in the registry record for this analysis. The designation of the trial as randomized does not, on its own, resolve possible uncertainty from missing outcomes, deviations from assigned treatment, or choices among multiple outcome time points.
The responsible conclusion is limited: the registry describes a completed phase 2 randomized comparison, identifies its primary symptom measure and secondary alcohol-use outcome, and records selected adverse-event counts. The registry entries do not support a numerical statement about comparative benefit, absence of benefit, or equivalence. They also do not justify treating the hypothesis in the study summary as if it were an observed result.
9. Statistical Methods Explained
Statistical interpretation depends on matching the analysis to the outcome and the way it was collected. The primary endpoint is a continuous CAPS-5 score, described as a mean with a 95% confidence interval. The registry's timeframe extends from baseline through 6 month follow-up, and its note indicates that the primary outcome has several categories or time points rather than one reduced comparison. The registry entries available do not identify which estimates correspond to which time points or categories, or how those repeated observations were analyzed.
What does a confidence interval communicate?
As a general explanation, a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the analysis. A point estimate alone can conceal how much sampling variability remains. An interval makes precision more visible, but it is not a guarantee that the true value lies within the interval, and it does not measure the importance of an effect. Interpreting an interval for a treatment contrast also requires knowing what contrast was estimated and how the model defined it. The registry record identifies 95% confidence intervals as the dispersion format for the primary endpoint, but the numerical estimates and interval limits are not reported in the registry record for this analysis.
Why do repeated assessments matter?
As a general statistical matter, measures collected repeatedly from the same participant are not independent observations. An analysis must account for the relationship between measurements from one person, as well as the timing and pattern of follow-up. Different choices can answer different questions: a comparison at a selected follow-up, a change from baseline, and an overall pattern across visits are not interchangeable. Since the registry note says the primary outcome has several categories or time points and is not reduced to one comparison, a single headline effect cannot be inferred. The exact repeated-measures method, visit-specific contrasts, and treatment of baseline values are not reported in the registry record.
What can the design tell us?
In general, random allocation is intended to make treatment groups comparable at the time of assignment, including with respect to factors that were not measured. A parallel design compares groups that receive their assigned approaches over the trial period. These design features help frame a treatment comparison, but they do not reveal whether allocation was concealed, what the masking procedure covered, or whether all assigned participants were included in each analysis. The registry identifies the study as randomized, single-masked, and parallel. Further operational details are not reported in the registry record in the registry record for this analysis.
How should the planning illustrations be read?
The sample-size material is described as a planning illustration based on the observed effect, not the trial's own design. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. For non-time-to-event outcomes, the illustrations are expressed as participants per arm for a stated power; time-to-event illustrations instead use a total number of events. These are conditional planning calculations, not observed power and not evidence that the original trial was designed around those assumptions. They should not be mistaken for the actual enrollment or for proof that an analysis had adequate precision. The registry record does not report the original sample-size justification in the registry record for this analysis.
Why can over-dispersion matter?
As a general statistical explanation, over-dispersion occurs when observed variability is greater than a model assumes. If a model understates variability, standard errors may be too small and confidence intervals too narrow. The choice of model should reflect the outcome's distribution and the design. The primary outcome is described as a mean of a continuous score, but the registry entries do not state whether over-dispersion was evaluated or which model was fitted. No conclusion about a specific modeling issue can be drawn from the endpoint description alone.
What is needed to assess a treatment contrast?
A complete interpretation would ordinarily require the estimate being compared, its uncertainty, the analysis population, and a clear account of the time point or summary being targeted. It can also be useful to know whether the result was adjusted for baseline values or other covariates and whether the analysis followed randomized assignment. These are general considerations, not claims about this trial's actual analysis. The registry record does not report those details in the registry record for this analysis. Because the primary outcome is not reduced to one comparison, the statistical interpretation must remain at the level of the outcome definition and the stated design.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when several outcomes, time points, categories, or contrasts are examined. In general, the more opportunities there are to identify a seemingly notable result, the more important it is to understand which analyses were planned and whether any adjustment or hierarchy was used. The registry indicates that the primary outcome has several categories or time points and is not reduced to one comparison. It also lists TLFB for Alcohol Use as a secondary outcome. The registry entries available do not describe a multiplicity strategy, a hierarchy among outcomes or time points, or whether reported p-values were adjusted. These details are not reported in the registry record.
Missing data can affect both the precision and interpretation of a treatment comparison. As a general matter, the consequences depend on how much information is missing, why it is missing, and the assumptions used in the analysis. The registry entries do not report follow-up completion by arm, the amount or pattern of missing CAPS-5 or TLFB data, or the methods used to address missingness. It is therefore not possible to assess whether the analyzed participants represent everyone randomized or whether missing outcomes could have influenced estimates.
The record also does not specify the analysis populations, such as whether analyses followed randomized assignment or were restricted by treatment exposure or outcome availability. It does not describe deviations from assigned treatment or the handling of participants who did not complete follow-up. These omissions limit assessment of how the randomized design was carried through into the analysis. They are uncertainties about reporting, not evidence that a particular method was or was not used.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Arm 1: Integrated Prolonged Exposure Therapy | 2 | 63 | 3.2% |
| Arm 2: Seeking Safety | 0 | 56 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Arm 1: Integrated Prolonged Exposure Therapy | 0 of 63 |
| Arm 2: Seeking Safety | 0 of 56 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Arm 1: Integrated Prolonged Exposure Therapy | 0 of 63 |
| Arm 2: Seeking Safety | 0 of 56 |
Most frequent serious adverse event terms
| Event term | Organ system | Arm 1: Integrated Prolonged Exposure Therapy | Arm 2: Seeking Safety |
|---|---|---|---|
| hospitalization for alcohol intoxication and mood stabilization | Psychiatric disorders | 2 of 63 | 0 of 56 |
Serious events with the highest arm-level rate: hospitalization for alcohol intoxication and mood stabilization (3.2%).
The registry reports serious adverse events separately for the two arms. In the Integrated Prolonged Exposure Therapy arm, 2 serious adverse events are reported among 63 participants at risk; in the Seeking Safety arm, 0 are reported among 56 participants at risk. Other adverse events are reported as 0 among 63 participants at risk in the first arm and 0 among 56 participants at risk in the second. Deaths are reported as 0 in each arm.
The registry also lists “hospitalization for alcohol intoxication and mood stabilization” as a serious adverse-event term, with 3.2% shown for that term. The registry entries available do not state the denominator or derivation for that percentage, so it should not be converted into a count or interpreted as a rate for a particular arm.
These counts are descriptive safety information, not a formal comparison of risk. A zero count does not establish that an event cannot occur, and low event counts generally give limited information about differences between groups. The registry entries do not provide event timing, duration, relatedness assessments, or a statistical comparison. Serious adverse-event counts should also be kept distinct from the primary CAPS-5 symptom outcome and the secondary alcohol-use outcome.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a phase 2 randomized, single-masked, parallel trial compared Integrated Prolonged Exposure Therapy with Seeking Safety for PTSD and alcohol use disorder. It identifies CAPS-5 as the primary symptom measure, with assessment from baseline through 6 month follow-up, and TLFB for Alcohol Use as a secondary outcome. It also records selected serious adverse-event counts. These design and measurement details clarify what the trial set out to compare.
They do not, in the registry record for this analysis, establish the direction or size of a treatment difference. The registry note says the primary outcome includes several categories or time points and is not reduced to one comparison. Numerical CAPS-5 estimates and confidence intervals are not reported in the registry record, and no numerical TLFB result is included. The stated hypothesis that exposure therapy would better sustain reductions in PTSD symptoms and alcohol use must therefore remain a hypothesis rather than a conclusion about the observed data.
In general, interpreting a clinical trial requires attention to estimates and uncertainty, not only to whether a study was randomized or completed. A confidence interval can indicate precision, while outcome definitions and analysis choices determine what question the estimate answers. Missing-data methods, analysis populations, and multiplicity procedures can also affect interpretation. The registry record does not report those details in the registry record for this analysis.
The safety counts are likewise limited. They report observed events in each arm, but the record details do not provide a formal risk comparison or detailed context for each event. A lack of reported events in a category is not proof of zero underlying risk. These counts cannot answer the primary symptom question.
Accordingly, this record supports a description of the trial's design, outcomes, and selected safety reporting, but not a quantified judgment about comparative efficacy or equivalence. It also does not establish that one approach is superior, or that the approaches have the same effect. Those conclusions would require interpretable comparative outcome estimates and adequate information about their uncertainty and analysis.
13. Why This Trial Matters Statistically
This trial is statistically notable because it compares two behavioral approaches within a population identified by comorbid PTSD and alcohol use disorder. Its randomized, parallel design gives a framework for evaluating treatment differences, while its primary endpoint uses a structured PTSD symptom measure. The CAPS-5 description also distinguishes symptom scoring from diagnostic classification, helping readers understand what the outcome represents and how its diagnostic rule is defined.
The study's question involves more than one outcome domain. PTSD symptoms are the primary outcome, while TLFB for Alcohol Use is listed as a secondary outcome. The registry summary links both domains in its rationale and hypothesis. This creates a useful reminder that a trial can address a broad clinical question while individual statistical results answer narrower questions about specified outcomes and time points. A result on one measure would not automatically establish a result on another.
The registry's indication that the primary outcome has several categories or time points is also important. Repeated measurements can provide information about change over time, but they require clear definitions of the contrast and suitable analysis. Without a single reduced comparison, readers should avoid treating a particular time point or trend as the sole trial result unless the analysis specifies that role. The registry entries available do not report a multiplicity strategy or detailed longitudinal model.
Finally, the sample-size material is explicitly a planning illustration based on the observed effect, rather than the trial's original design. That distinction matters: a calculation based on an observed effect is not observed power, and it does not replace a prospective sample-size justification. The trial therefore illustrates why design information, endpoint definitions, estimated effects, uncertainty, and analysis details all need to be read together.
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 entries available for this analysis do not include numerical CAPS-5 estimates or confidence interval limits. The registry note states that the primary outcome has several categories or time points and is not reduced to one comparison. This prevents a direct interpretation of one primary treatment contrast and leaves the stated hypothesis unquantified. Numerical TLFB results are also not reported in the registry record.
Important analysis details are not reported in the registry record. These include the exact statistical model, the definition of each primary-outcome contrast, the analysis populations, the handling of baseline measurements, and the approach to missing data. The record details also do not describe the multiplicity strategy, allocation procedures, or which roles were masked. These reporting gaps limit evaluation of how the randomized design translated into the outcome analyses.
The enrollment figure does not establish how many participants contributed to a particular endpoint or follow-up assessment. The registry entries available do not provide outcome completion by arm or information about treatment adherence and deviations from assigned treatment. As a result, the available information cannot show whether missing outcome data or incomplete treatment exposure affected the analysis.
Safety reporting is also limited to the listed counts and term. Event timing, duration, relatedness, and the denominator behind the listed 3.2% are not reported in the registry record. The reported counts do not amount to a formal comparison of safety between arms.
These limitations concern the information available in the registry record and do not establish that analyses or procedures were absent from the full trial documentation. They mean that conclusions should remain bounded by the record's reported design, outcome definitions, and descriptive safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Integrated Alcohol Disorder and PTSD Treatment — NCT01601067.
- Registry record last updated 2019-08-08; status last verified 2019-08.
- Results first posted 2019-08-08.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry describes a completed phase 2, randomized, single-masked, parallel trial with enrollment of 168. It compared Integrated Prolonged Exposure Therapy, combining prolonged exposure with elements of Integrated Cognitive Behavioral Therapy for alcohol use disorder, with Seeking Safety. The study concerned PTSD and alcoholism.
The primary outcome was CAPS-5 score from baseline through 6 month follow-up, described as a mean with a 95% confidence interval. TLFB for Alcohol Use was listed as a secondary outcome. The primary outcome was not reduced to one comparison because it included several categories or time points. The record details do not report numerical outcome estimates, detailed analysis methods, missing-data procedures, or a multiplicity strategy.
Serious adverse events were reported as 2 among 63 at risk in the first arm and 0 among 56 at risk in the second. Other adverse events were 0 in both arms, and deaths were 0 in both arms. The record also lists a serious-event term with 3.2%. These descriptive details do not establish a comparative treatment effect.