Novel Interventions for GWVI: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Novel Interventions for GWVI (NCT02661997), a randomized na study. The primary outcome is Change in Brief Pain Inventory - Short Form (BPI) - Pain Interference.

2. Clinical Question

In plain terms, the study asked whether the two behavioral programs were associated with different average changes in the extent to which pain interfered with daily functioning. The BPI Pain Interference measure covers impacts such as general activity, mood, walking, work, relationships, sleep, and enjoyment of life. Its items use higher scores to represent worse outcomes. The registry record identifies change in this measure as primary, but it does not provide the arm-specific changes, the difference between arms, or uncertainty around that difference. Consequently, the clinical question can be described, but the registry record does not support a conclusion about the direction or precision of the comparative result.

3. Trial Design

This was a completed, randomized, parallel-group behavioral trial with single masking. Its title is Novel Interventions for GWVI, and the official title is Novel Interventions for Gulf War Veterans' Illnesses. The sponsor was the VA Office of Research and Development. The registry lists the phase as NA. Enrollment was 114 participants.

The study compared Tai Chi Intervention with Wellness Intervention. The Tai Chi program was based on classical Yang Tai Chi and was described as moderate-intensity exercise. Its scheduled sessions lasted 60 minutes, twice a week for 12 weeks. The Wellness group received wellness education, with two 60-minute sessions per week for 12 weeks. The registry describes both as behavioral interventions.

The study began on 2017-06-01, and primary completion was recorded as 2023-09-29. The record describes a disruption and change in delivery: after 53 Veterans had been randomized, the trial was halted in March 2020 because of the onset of COVID-19. In late 2020, the study shifted from in-person participation to a fully remote format, with interventions delivered by synchronous video teleconferencing. The record says an additional 61 Veterans were randomized after the shift and reports a study grand total of 114 Veterans. It does not report whether delivery format was incorporated into the primary statistical analysis or whether the change affected outcome measurement.

Randomization is intended to create groups that are comparable, on average, at the point of assignment. A parallel-group design assigns participants to one intervention group rather than having each participant receive both interventions in sequence. Single masking means that one party was masked, but which party or parties were masked is not reported in the registry record. Details of the randomization procedure, allocation concealment, and the intended masking procedures are also not reported. These omissions limit the extent to which the design can be reconstructed from the registry record alone.

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.

Baseline Assessment

Post-Treatment Assessment

3-month Follow-up Assessment

9-month Follow-up Assessment

Analysis population for the primary outcome, as defined in the registry: 98 Veterans participated in the post-treatment assessment, however only 91 completed full data on this measure.

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 Change in Brief Pain Inventory - Short Form (BPI) - Pain Interference, measured over Change from baseline to post-treatment at 12 weeks.

The primary endpoint was change in the Brief Pain Inventory Short Form Pain Interference score from baseline to post-treatment at 12 weeks. This self-report measure asks how pain affects functioning across areas including general activity, mood, walking activity, work, relationships, sleep, and enjoyment of life. The registry describes the BPI as a measure of both pain severity and interference, and identifies the Pain Interference subscale as the reported outcome of interest.

The subscale contains seven items, each rated from 0 to 10; higher scores indicate a worse outcome. Item values are converted to a mean score, preserving the same metric as the individual items. The score ranges from a minimum of 0 to a maximum of 10. The registry gives test-retest reliability estimates ranging from .83 to .98 across a variety of pain populations. Reliability concerns the consistency of measurement; it does not establish that a treatment has an effect or that a particular observed difference is clinically important.

Pain interference is used because pain can affect daily activities and participation beyond pain intensity alone. A change score is intended to describe how the measure differs between baseline and the post-treatment assessment. However, the registry record does not report the group means, change estimates, between-group contrast, confidence interval, or significance test for this endpoint. It therefore describes what was measured, but not the numerical primary outcome result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary outcome as a continuous measure summarized using a mean and standard deviation. A mean represents the average score or change in a group. A standard deviation describes how spread out participant values are around that average. These quantities describe the distribution of observed measurements; they do not, by themselves, establish the uncertainty in a comparison between randomized groups.

What does a comparison of mean change represent?

In general, an analysis of change compares how the outcome shifts from baseline to a later assessment. The between-group contrast asks whether the average change differs between the assigned interventions. It is distinct from looking at whether one group changed from its own baseline. A within-group change can reflect many influences, including natural variation or changes over time; the randomized comparison is the relevant basis for evaluating differences between the assigned groups.

The registry specifies the timing as change from baseline to post-treatment at 12 weeks. It does not report the actual group means or changes, the form of the primary contrast, or the statistical model used. It is therefore not possible to determine from the registry record whether the comparison used a change-score model, an adjustment for baseline values, or another approach. The analysis plan, including any covariates and assumptions, is not reported in the registry record.

How should uncertainty be understood?

In general, a confidence interval describes the uncertainty around an estimated effect under the assumptions of the statistical method. A narrower interval indicates greater precision, while a wider interval indicates less precision. The interval also helps readers judge which effect sizes remain compatible with the observed data. The registry record does not report a confidence interval for the primary outcome, so the precision of the comparison is unavailable.

A p-value, in general, describes how unusual the observed data or more extreme data would be under a specified null hypothesis and statistical model. It is not a measure of the size or clinical importance of an effect. No primary-outcome p-value or corresponding test result is reported in the registry record. Since the estimate, interval, and test result are absent, none can be reconstructed from the enrollment and assessment counts alone.

What do the planning assumptions mean?

The record describes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says that the effect to detect is expressed as a stated fraction of the observed effect. For time-to-event outcomes, the described planning convention concerns total events; for other outcomes, it concerns participants per arm. The numerical planning illustrations are not reported in the registry record, and the stated assumptions should not be mistaken for the trial's original design justification. The registry record does not report the trial's own sample-size justification.

More generally, sample-size planning estimates how much information a study might need under chosen assumptions. A planning calculation is not an observed result and is not observed power. It cannot establish whether a trial found an effect or whether its estimate is precise. In this record, the planning framework is described, but the numerical illustration and the observed primary-outcome estimate are unavailable.

Why does the outcome scale matter?

The BPI Pain Interference measure is reported as a mean score on a scale from 0 to 10, with higher values representing worse outcomes. Its seven items are converted to a mean, so the reported score remains in the metric of the items. Interpreting a change requires knowing both the direction and the size of the change, and understanding whether the comparison is between groups or within a group. Because the numerical results are not reported, these interpretations cannot be made for this trial.

General statistical practice also considers whether model assumptions are appropriate. For continuous outcomes, analysts may examine the distribution of values and residuals, the influence of unusual observations, and whether the chosen model adequately represents the data. Over-dispersion is particularly relevant to some count-data models: it means variability exceeds what a model assumes, which can make uncertainty estimates too small if ignored. That general issue does not establish that over-dispersion affected this continuous primary endpoint. The registry record does not report model diagnostics or an analysis method from which to assess such assumptions.

The outcome record lists 36 outcome measures and 34 analyses. This indicates that the trial registry includes multiple outcome and analysis entries, but it does not reveal the statistical procedures used for each. The record does not report a multiplicity plan for interpreting multiple tests, or whether the primary outcome analysis accounted for other outcomes or analyses. Readers should not infer an adjustment—or the absence of one—from the counts alone.

10. Multiplicity, Missing Data and Analysis Populations

The record lists 36 outcome measures and 34 analyses. It also identifies secondary outcomes covering fatigue, physical and mental health, walking, cognitive tests, and physical performance. Having multiple outcomes or analyses raises a general interpretive issue: repeated testing can make isolated findings harder to distinguish from chance findings. A prespecified strategy may identify which result is primary and how other results are to be interpreted. The registry record does not report a multiplicity strategy, such as whether statistical tests were adjusted or how secondary outcomes were prioritized.

The primary outcome is described as change from baseline to post-treatment at 12 weeks, and the registry notes that the outcome has several categories or time points and is not reduced to one comparison. The record does not supply a single numerical primary comparison. It also does not report whether analyses across categories or time points were prespecified, how they were modeled, or how any resulting tests were handled. These omissions prevent a full assessment of the primary analysis and its relationship to other analyses.

Missing data are relevant to the BPI outcome: 98 Veterans participated in the post-treatment assessment, while 91 completed full data on this measure. The reasons for missing data, the number of missing items within otherwise completed assessments, and the statistical approach to incomplete outcomes are not reported in the registry record. It does not say whether the analysis used only participants with complete data, imputed missing values, or followed another method.

The record does not report whether the primary analysis followed an intention-to-treat principle, how participants were classified if they did not complete assigned sessions, or which participants were included in each analysis. These analysis-population details are necessary to understand how randomization was preserved in the analysis and how missing outcomes may affect interpretation. The assessment and analysis counts alone do not resolve these questions.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: detox from opiates (1.8%), hospitalization for cardiac symptoms (1.8%).

The registry lists serious adverse events, other adverse events, and deaths separately for the two intervention groups. For Tai Chi Intervention, 58 participants were listed as at risk for serious events and 58 for other events; the record lists 0 serious events, 3 other events, and 1 death. For Wellness Intervention, 56 participants were listed as at risk for serious events and 56 for other events; the record lists 2 serious events, 2 other events, and 0 deaths.

The registry names Detox from opiates and Hospitalization for cardiac symptoms as serious-event terms, each listed as 1.8%. These event counts and terms describe what was recorded in the registry. They do not establish that an intervention caused or prevented an event. The record does not provide enough detail to assess event timing, duration, severity beyond the serious-event classification, or the relationship of each event to intervention exposure.

Event counts should not be treated as a formal comparison of safety unless the analysis method and relevant follow-up are known. The registry record does not report a statistical comparison, uncertainty interval, or a detailed account of how adverse events were collected and classified. The at-risk counts provide the listed group denominators, but they do not clarify whether all participants had the same duration of observation or exposure. The death counts are reported separately; the registry record does not state their causes or relationship to study participation. These figures are descriptive registry entries, not a complete assessment of comparative safety.

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

The record establishes that a randomized, parallel-group study compared Tai Chi Intervention with Wellness Intervention for Gulf War Veteran's Illness. It identifies change in BPI Pain Interference from baseline to post-treatment at 12 weeks as the primary outcome and describes how that measure is scored. It also records participant enrollment, the shift to remote delivery, and the number of participants with post-treatment and full BPI data.

However, the registry record does not report the numerical primary outcome results. There are no arm-specific mean changes, no between-group estimate, no confidence interval, and no primary-outcome p-value reported in the registry record. As a result, the posted information does not establish which group had a larger change, whether the groups differed, or how precise a comparative estimate would be. It also does not establish whether any difference, if estimated, would be clinically important.

These limits are not resolved by the study's completed status, its enrollment total, the intervention descriptions, or the adverse-event counts. None of these registry entries substitutes for an outcome estimate. Likewise, planning assumptions do not provide evidence about the observed result; sample-size planning is a design exercise, not an outcome finding.

The record also leaves important analysis details unspecified, including the primary statistical model, the handling of incomplete outcome data, and the analysis population. A change from in-person to remote delivery is part of the study context, but no result is reported that separates outcomes by delivery format. The available information therefore supports a description of the research question and the recorded study conduct, not a conclusion about the comparative effectiveness of the two interventions.

For readers, the central distinction is between knowing what a trial set out to measure and knowing what it found. The registry record provides the former for the primary endpoint but does not provide the numerical result needed for the latter. Any interpretation of the primary comparison must remain limited accordingly.

13. Why This Trial Matters Statistically

This trial is statistically notable for the gap between a clearly identified primary outcome and the absence of its numerical result in the registry record. The endpoint, scale direction, timing, and assessment completeness are described, but the comparative estimate and its uncertainty are not. This illustrates why a study's question and design cannot replace the results needed to judge an observed effect.

The record also documents a substantial change in how the intervention was delivered during the trial. Recruitment and randomization were interrupted after 53 Veterans had been randomized, followed by a move to synchronous video teleconferencing and additional randomization. Such operational changes are important context for interpreting a trial. The record does not report whether delivery mode was incorporated in the analysis, so its statistical implications cannot be assessed from the posted information.

Assessment completeness matters as well. The record reports 98 post-treatment assessment participants and full BPI data for 91. Those numbers flag that outcome information was not complete for all participants who attended post-treatment assessment, but do not explain why. Without the reasons for missingness and the handling method, readers cannot assess possible bias or the robustness of the primary analysis.

Finally, the record lists many outcomes and analyses but does not report a multiplicity strategy. That is a useful reminder that interpretation depends not only on individual estimates but also on how a study planned and handled multiple comparisons. The trial's registry information supports careful questions about design, analysis, and reporting; it does not support a numerical claim about the primary outcome.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most consequential limitation for statistical interpretation is that numerical results for the primary outcome are not reported in the registry record. The group-level changes, between-group contrast, and uncertainty are unavailable. Thus, readers cannot assess the magnitude, direction, or precision of the primary comparison from this record.

Outcome completeness is another limitation. The record states that 98 Veterans participated in the post-treatment assessment and that 91 had full data on the BPI measure. It does not report why the remaining participants or assessments lacked full data, whether missingness differed between groups, or how incomplete records were handled. Without that information, the potential effect of missing outcomes on the estimate cannot be judged.

The trial's delivery changed from in-person to remote synchronous video teleconferencing after a halt in March 2020. The record does not report whether assessment procedures changed, whether delivery mode was considered in the analysis, or whether outcomes differed by delivery format. This limits interpretation of the consistency of study conduct across the trial.

Several analytic details are not reported in the registry record: the randomization procedure, the identity of the masked party or parties, the primary statistical model, the analysis population, the handling of protocol deviations, and any multiplicity strategy. The registry also does not report the trial's own sample-size justification. These gaps do not establish that any particular method was absent; they mean that the record does not permit its assessment.

Finally, the safety entries are descriptive and lack detailed event context, follow-up information, and statistical comparisons. Taken together, these limitations make the registry record useful for understanding the study question and broad conduct, but insufficient for a detailed evaluation of the primary estimate or comparative safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Novel Interventions for GWVI — NCT02661997.
• Registry record last updated 2025-11-13; status last verified 2025-10.
• Results first posted 2024-11-07.
• 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

NCT02661997, Novel Interventions for GWVI, was a completed, randomized, single-masked, parallel-group behavioral trial sponsored by the VA Office of Research and Development. It enrolled 114 Veterans and compared Tai Chi Intervention with Wellness Intervention for Gulf War Veteran's Illness. The primary outcome was change in BPI Pain Interference from baseline to post-treatment at 12 weeks.

The trial began on 2017-06-01, and primary completion was recorded as 2023-09-29. After 53 Veterans had been randomized, the trial halted in March 2020 because of COVID-19. It shifted to fully remote delivery in late 2020 and randomized an additional 61 Veterans. The record reports 98 post-treatment assessment participants and full BPI data for 91.

Numerical primary-outcome results, the analysis method, missing-data handling, and the multiplicity strategy are not reported in the registry record. Consequently, the comparative primary outcome and its precision cannot be interpreted from the posted information.