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 Evaluation of Stepped Care for Chronic Pain in Iraq/Afghanistan Veterans (ESCAPE) (NCT00386243), a randomized na study. The primary outcome is Roland-Morris Disability Questionnaire.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00386243 |
| Phase | NA |
| Condition | Low Back Pain, Pain, Pain, Intractable |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 242 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
Veterans with chronic pain, including pain conditions recorded as low back pain, pain, and intractable pain. The study description refers to OIF/OEF veterans. Enrollment was 242, while baseline data were available for 241 participants.
Intervention
Stepped care for pain. The registry describes FDA-approved analgesic therapy and a 12-week pain self-management program, followed, if pain did not improve, by a 12-week cognitive behavioral therapy program. The intervention list also names co-analgesic therapy and opioid analgesics.
Comparator
Usual care from participants’ providers, with no study intervention undertaken in that arm. Participants in both arms were scheduled to complete outcome surveys during the study.
Primary question
Does stepped care reduce pain-related disability more than usual care, as assessed with the Roland-Morris Disability Questionnaire at baseline and 9 months? The registry also describes a hypothesis concerning psychological distress, but comparative endpoint results are not reported in the registry record.
The primary question is a comparison between randomized care strategies, not a test of whether any single component works in isolation. Stepped care combines medication-related and behavioral components, with cognitive behavioral therapy described as a subsequent step when pain does not improve. The comparison therefore concerns the overall strategy against usual care.
The registry describes disability and psychological distress as the two primary hypotheses. The reported primary outcome measure is the Roland-Morris Disability Questionnaire. Secondary outcomes listed include mental health, depression, post-traumatic stress, anxiety, and pain catastrophizing measures. The record does not report the comparative results for these measures, so the direction, size, or precision of any effect cannot be established from the registry information.
3. Trial Design
ESCAPE is recorded as a randomized, parallel-group trial with no masking. The study status is completed. The sponsor is the VA Office of Research and Development. The record lists enrollment as 242 and the study dates as 2007-12 for the start and 2012-05 for primary completion.
Participants were assigned to usual care or stepped care. Usual care meant care from participants’ providers without a study intervention. The stepped-care description includes FDA-approved analgesic therapy, a 12-week pain self-management program, and, if pain did not improve, a 12-week cognitive behavioral therapy program. The intervention list additionally names co-analgesic therapy and opioid analgesics. The registry does not provide further detail about how treatment decisions were operationalized or how adherence to each component was assessed.
The primary outcome was the Roland-Morris Disability Questionnaire, described as a mean score on a scale. The timeframe is baseline and 9 months. The registry reports baseline data for 241 participants: 120 in usual care and 121 in stepped care. It states that, at 9 months, 7 usual-care participants and 13 stepped-care participants withdrew, leaving 114 and 108 available for analysis, respectively. The specific analysis population and the handling of missing outcome measurements are not reported in the registry record.
The trial record lists seven outcome measures and zero analyses. Comparative estimates, uncertainty intervals, and test results for the primary endpoint are not reported in the registry record. The record also does not report a statistical analysis plan or sample-size justification. The clinical question can therefore be described from the design and outcome definitions, but the treatment comparison cannot be evaluated from the registry results presented in the 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.
Overall Study
| Stage | Usual Care | Stepped Care |
|---|---|---|
| STARTED | 121 | 121 |
| COMPLETED | 114 | 108 |
| NOT COMPLETED | 7 | 13 |
Analysis population for the primary outcome, as defined in the registry: We had baseline data available for 241 participants; 120 in the usual care arm and 121 in the stepped care arm. At 9 months, 7 participants withdrew from the study leaving 114 usual care participants available for analysis. In the stepped care arm, 13 participants withdrew leaving 108 available for analysis
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 | Usual Care | Stepped Care | Total |
|---|---|---|---|---|
| Participants analysed | 121 | 121 | 242 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 121 | 120 | 241 |
| Age, Categorical: >=65 years | Participants | 0 | 1 | 1 |
| Age, Continuous | years | 38.2 (SD 10.5) | 36.4 (SD 10.1) | 36.7 (SD 10.3) |
| Sex: Female, Male: Female | Participants | 16 | 12 | 28 |
| Sex: Female, Male: Male | Participants | 105 | 109 | 214 |
| Region of Enrollment: United States | participants | 121 | 121 | 242 |
6. Primary Endpoint
The registry lists the primary outcome as Roland-Morris Disability Questionnaire, measured over at baseline and 9 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | scores on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Roland-Morris Disability Questionnaire, a pain-specific measure of disability. The registry describes it as a 24-item questionnaire about physical functions likely to be affected by back pain. The score is formed by adding the number of items checked by the participant, with a range of 0-24. Higher scores indicate greater disability.
This measure addresses the functional consequences of pain rather than pain intensity alone. A participant may experience pain while retaining different levels of ability to carry out physical activities; a disability measure captures that aspect of the clinical question. In this trial, it was used to assess whether the stepped-care strategy was associated with a difference in pain-related disability compared with usual care.
The registry identifies the outcome as a mean of a continuous measure and gives baseline and 9 months as the assessment time points. A comparison of group means could describe an average difference, but the record does not report the group means, the estimated difference, its uncertainty, or the analysis used. The record therefore establishes what the endpoint measures and how higher scores should be interpreted, but not what the endpoint results were.
As a general measurement point, a score is most informative when interpreted alongside its scale, direction, timing, and uncertainty. A mean can summarize the group’s average score, while also concealing variation among participants. The registry lists standard deviation as the dispersion measure, but does not report the actual endpoint standard deviations.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the intended comparison and the primary outcome, but it does not report a numerical comparison of Roland-Morris Disability Questionnaire scores. There is no posted group mean, mean difference, confidence interval, or p-value for the primary endpoint in the record. Consequently, the magnitude, direction, and precision of the primary treatment contrast cannot be interpreted from these registry data.
The record’s statement of the primary hypotheses is not itself evidence that either hypothesis was supported. The hypotheses concern reducing pain-related disability and psychological distress. A hypothesis describes the question the investigators intended to test; evaluating it requires outcome results and an account of the analysis. Those comparative results are not reported in the registry record.
The baseline and follow-up counts provide context for outcome availability. Baseline data were available for 241 participants, split as 120 in usual care and 121 in stepped care. The registry reports withdrawals by 9 months and gives the numbers available for analysis in each arm. These figures do not, on their own, show whether the observed outcome values differed between arms or whether missing measurements affected the comparison. The analysis population and missing-data method are not reported in the registry record.
As a general statistical principle, an effect estimate and its confidence interval answer different but related questions. The estimate describes the observed contrast under the selected analysis; the interval conveys the range of values reasonably compatible with the data and model. Without either, readers cannot judge how large an estimated contrast was or how precisely it was estimated. A p-value alone, even if reported, would not quantify the effect’s size or clinical importance.
The registry lists secondary measures including SF-Mental Component Summary, PHQ-9 Depression, PTSD Checklist-17 Civilian Version, GAD-7 Anxiety Score, and Pain Catastrophizing Scale. Their inclusion indicates that several domains were assessed, but outcome names do not establish that a difference was observed. Comparative results for these outcomes are not reported in the registry record.
The serious adverse event figures are separate from the disability outcome. They report counts in each arm, but they cannot substitute for the missing primary endpoint analysis. Nor do the figures alone establish that the intervention caused or prevented an event. The adverse-event information should be read as a descriptive account of events recorded in the registry, with the limits discussed in the safety interpretation.
Overall, the available registry information supports a description of the trial design, intended outcomes, and some participant and safety counts. It does not support a conclusion about the direction or size of the randomized comparison on disability or psychological distress. Any interpretation of the treatment effect would require results not reported in the registry record.
9. Statistical Methods Explained
The trial is recorded as randomized and parallel-group. Randomization is intended, in general, to make treatment assignment independent of participants’ baseline characteristics, so that an outcome contrast can be interpreted as a comparison of assigned strategies under the assumptions of the analysis. Random assignment does not guarantee that every baseline characteristic will be identical between arms, especially in a finite study. The record does not describe the randomization sequence, allocation concealment, or any stratification factors.
What does a mean comparison represent?
The primary outcome is a continuous score, and the registry identifies the parameter as a mean. A mean comparison summarizes the average score in one assigned arm relative to the other. Because larger Roland-Morris scores represent more disability, the direction of a mean contrast would need to be read using that scale direction. No group means or mean contrast are reported in the registry record, so no direction can be assigned to the result.
The registry lists standard deviation as the measure of dispersion. In general, a standard deviation describes how spread out participant scores are around their group mean. It is not the uncertainty in the difference between group means; that uncertainty depends on the observed spread and the amount of available information, as well as the analysis model. The actual standard deviations and the model used for the primary comparison are not reported in the registry record.
What would a confidence interval add?
In general, a confidence interval expresses uncertainty around an estimate under a specified statistical model and procedure. A narrow interval indicates greater precision than a wide interval, while an interval spanning effects in substantially different directions or magnitudes leaves greater uncertainty about the contrast. It does not describe the range of individual participant outcomes. The registry record does not report a confidence interval for the primary outcome.
A p-value, as a general concept, measures how surprising the data would be under a specified null hypothesis and statistical model. It does not measure the probability that the null hypothesis is true, and it does not convey the size or practical importance of an effect. No primary-outcome p-value is reported in the registry record. The record also does not report whether the primary analysis was adjusted, which test was used, or whether a particular significance threshold was prespecified.
Why do analysis populations matter?
In a randomized trial, an analysis based on assigned groups can preserve the original comparison, while analyses restricted to participants with observed follow-up data can be affected if follow-up availability is related to treatment assignment, outcomes, or participant characteristics. These are general considerations, not statements about what happened in this trial. The registry reports baseline availability and 9-month withdrawals and available-for-analysis counts, but does not identify the analysis population or explain how missing outcome values were handled.
As a general matter, complete-case analysis uses participants with observed measurements for the endpoint, whereas other methods may use assumptions and models to incorporate incomplete records. No particular method can be attributed to this trial from the registry record. The reasons for withdrawal, patterns of missingness, and sensitivity analyses are also not reported in the registry record.
What does over-dispersion mean for count outcomes?
For outcomes recorded as counts, a simple model may assume that the mean and variance are linked in a particular way. Over-dispersion means the observed variability is greater than that assumed by such a model. In general, ignoring over-dispersion can make uncertainty estimates too small and statistical evidence appear more precise than it is. This concept does not establish that over-dispersion occurred in this trial. The primary endpoint is continuous, and the registry does not report a statistical model for the primary analysis.
How should planning illustrations be read?
The registry’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The stated effect to detect is a fraction of the observed effect. Such an illustration is a conditional planning exercise, not evidence that the trial was designed with those assumptions, and not an observed power calculation. The registry does not report the trial’s own sample-size justification or the specific planning results in the information.
More generally, power calculations depend on assumptions about the effect, outcome variability, allocation, significance threshold, and analysis. If an assumed effect is smaller, a study generally requires more information to distinguish it from random variation at a chosen threshold. These are general statistical principles. They do not recover the assumptions or design rationale of ESCAPE, which are not reported in the registry record.
The registry marks the primary outcome as having several categories or time points and indicates that it was not reduced to one comparison. This means a single primary contrast is not available in the posted analysis representation. The specific comparisons, model structure, and treatment of repeated assessments are not reported in the registry record. As a result, readers should not infer a particular longitudinal model, baseline adjustment, or time-by-treatment interaction analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists multiple outcome measures, including the Roland-Morris Disability Questionnaire and measures of mental health, depression, post-traumatic stress, anxiety, and pain catastrophizing. When investigators test multiple outcomes or contrasts, the chance of obtaining at least one apparently unusual result by chance can increase. As a general statistical principle, multiplicity procedures may control this risk or define a hierarchy of primary and secondary tests. The registry record does not report a multiplicity adjustment, testing hierarchy, or prespecified approach to interpreting the several outcomes.
The record describes two primary hypotheses: pain-related disability and psychological distress. It also lists secondary measures and gives a primary endpoint timeframe of baseline and 9 months. However, the registry’s outcome entry notes that the primary outcome has several categories or time points and was not reduced to one comparison. The analysis plan, the intended contrasts across time, and the relationship between the hypotheses and the listed measures are not reported in the registry record. No adjustment strategy should therefore be assumed.
Missing data are also relevant to interpretation. The registry reports baseline data for 241 participants, with 120 in usual care and 121 in stepped care. At 9 months, it reports 7 withdrawals in usual care and 13 in stepped care, with 114 and 108 participants available for analysis, respectively. These counts describe availability, but do not reveal why participants withdrew, whether withdrawal was related to outcomes, or how missing measurements were treated statistically.
In general, missing-data methods rely on assumptions about why observations are missing. Different assumptions can lead to different estimates, so sensitivity analyses can help show whether conclusions depend on those assumptions. The registry record does not report the missing-data method, the analysis population, or sensitivity analyses. These omissions limit assessment of the robustness of any outcome comparison, and the comparative outcome results themselves are not reported.
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 |
|---|---|---|---|
| Usual Care | 1 | 121 | 0.8% |
| Stepped Care | 6 | 121 | 5.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Usual Care | 0 of 121 |
| Stepped Care | 4 of 121 |
Most frequent serious adverse event terms
| Event term | Organ system | Usual Care | Stepped Care |
|---|---|---|---|
| hospital stay longer than 24 hours | Psychiatric disorders | 1 of 121 | 3 of 121 |
| hospitalization for longer than 24 hours | Nervous system disorders | 0 of 121 | 2 of 121 |
| hospitalization for longer than 24 hours | Respiratory, thoracic and mediastinal disorders | 0 of 121 | 1 of 121 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Usual Care | Stepped Care |
|---|---|---|---|
| Medication side effects | Nervous system disorders | 0 of 121 | 2 of 121 |
| Medication side effects | Gastrointestinal disorders | 0 of 121 | 2 of 121 |
Serious events with the highest arm-level rate: hospital stay longer than 24 hours (2.5%), hospitalization for longer than 24 hours (1.7%).
The registry reports serious adverse events for both arms, with 121 participants at risk in each. It records 1 serious adverse event in usual care and 6 in stepped care. For other adverse events, it records 0 in usual care and 4 in stepped care. Deaths are not reported in the registry record.
These are descriptive counts. They do not establish whether an event was caused by the assigned care strategy, and the registry record does not provide an adjusted comparison or uncertainty interval for these figures. Event counts alone also do not describe severity beyond the serious-event classification, timing, duration, or clinical context of each event. The record lists “hospital stay longer than 24 hours” at 2.5% and “hospitalization for longer than 24 hours” at 1.7% among the top serious terms, but does not establish from the information presented how those terms map to each arm.
As a general statistical point, safety comparisons require careful attention to how events and participants are counted, how follow-up time is defined, and whether one participant can contribute more than one event. Those details are not reported in the registry record. The posted counts should therefore be read as the recorded event figures, not as a definitive estimate of comparative safety.
12. What the Result Does, and Does Not, Mean
The registry record can establish that ESCAPE was a randomized, parallel-group comparison of stepped care and usual care for chronic pain in Iraqi/Afghanistan veterans. It identifies pain-related disability as the reported primary outcome and describes how the Roland-Morris Disability Questionnaire is scored. It also reports participant availability at baseline and 9 months, as well as serious and other adverse-event counts.
What the record does not establish is whether stepped care reduced disability or psychological distress relative to usual care. The comparative outcome estimates are not reported in the registry record. Without those estimates, there is no basis in this record for describing an observed treatment effect as favorable, unfavorable, large, small, or precise. The stated hypotheses must not be mistaken for findings.
Even when comparative results are available, an average difference would not describe every participant’s experience. A group mean summarizes outcomes across participants, and uncertainty around that estimate matters when judging how strongly the data support a range of possible effects. The registry record does not report the primary outcome means, a mean difference, or its uncertainty.
The intervention is a care strategy with several components, rather than a comparison of a single isolated treatment. Thus, any result from such a randomized comparison would concern assignment to the stepped-care approach as implemented, relative to usual care. It would not by itself identify the separate contribution of medication, self-management, or cognitive behavioral therapy. The registry does not report adherence or component-specific comparisons.
The safety counts likewise do not prove that the intervention caused or prevented serious events. They are descriptive registry figures without a reported comparative statistical analysis. Further information about event definitions, timing, and participant-level event patterns would be needed for a fuller assessment.
In short, the registry record documents the question, design, endpoint definition, and selected participant and safety counts. It does not report the comparative clinical outcome results needed to answer the central efficacy question. No treatment recommendation follows from the information reported.
13. Why This Trial Matters Statistically
This trial is statistically notable as a randomized comparison of a multicomponent stepped-care strategy with usual care, with pain-related disability assessed using a continuous questionnaire score. That design raises familiar questions about the estimand: whether the intended comparison concerns assignment to the care strategy, receipt of its components, or outcomes under a specified follow-up approach. The registry describes the arms but does not report the analysis plan needed to resolve those distinctions.
The trial also highlights the importance of connecting an endpoint definition to its analysis. The Roland-Morris score has a clear direction, with higher scores indicating greater disability, and is measured at baseline and 9 months. Yet a scale and timeframe alone do not disclose how follow-up values were compared, whether baseline scores were incorporated analytically, or how multiple time points were handled. These details are not reported in the registry record.
Participant availability deserves attention because the registry records withdrawals and the numbers available at 9 months in both arms. A sound interpretation must distinguish randomized enrollment from the participants contributing endpoint data, then consider whether missingness could affect the estimated contrast. The record does not give the reasons for withdrawal or missing-data methods, so that assessment cannot be completed.
Finally, this registry record illustrates why design information and outcome information should not be conflated. Randomization and a stated hypothesis describe the intended study; they do not establish an outcome. Without comparative estimates and uncertainty, the central statistical question remains unanswered by the posted registry results. That distinction is essential when reading completed trial records.
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 main limitation for interpreting this trial from the registry record is the absence of comparative primary-outcome results. Group means, the estimated contrast, uncertainty intervals, and test results are not reported. The same applies to the registry’s hypothesis concerning psychological distress and the listed secondary outcomes.
Although the primary outcome timeframe is baseline and 9 months, the record does not report the specific comparison across those assessments or the statistical model. It also does not describe adjustment for baseline score, repeated-measures handling, covariates, or the analysis population. These omissions prevent a detailed appraisal of the primary analysis.
The registry reports withdrawals and participants available for analysis at 9 months, but not the reasons for withdrawal or the missing-data method. It is therefore not possible to determine from the record whether missing outcome data could have influenced the estimated comparison. The record also does not report sensitivity analyses addressing missingness.
The intervention description identifies several treatment components, but the registry does not report treatment adherence, exposure to individual components, or component-specific effects. The comparison therefore cannot be decomposed into the contributions of its behavioral and medication elements on the basis of the available record.
The registry record does not report a sample-size justification, statistical analysis plan, multiplicity strategy, interim analyses, or details of randomization and allocation concealment. These details should not be inferred from the randomized label or from the planning assumptions described for sample-size illustrations. The adverse-event figures are also limited: event timing, definitions beyond the recorded categories, and a comparative safety analysis are not reported.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of Stepped Care for Chronic Pain in Iraq/Afghanistan Veterans (ESCAPE) — NCT00386243.
- Registry record last updated 2019-07-05; status last verified 2019-05.
- Results first posted 2014-05-26.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
ESCAPE is recorded as a completed, randomized, parallel-group trial with no masking and enrollment of 242. It compared stepped care for chronic pain with usual care in Iraqi/Afghanistan veterans. The stepped-care description includes analgesic therapy, a pain self-management program, and cognitive behavioral therapy if pain did not improve.
The primary outcome was the Roland-Morris Disability Questionnaire, a 0-24 score in which higher scores indicate greater disability, assessed at baseline and 9 months. Baseline data were available for 241 participants. The registry also reports 9-month withdrawals and numbers available for analysis in each arm.
Comparative primary and secondary outcome results are not reported in the registry record. Serious adverse-event counts are recorded as 1 for usual care and 6 for stepped care; other adverse-event counts are 0 and 4, respectively. The record does not report deaths or a comparative statistical analysis of these safety figures.