Improving Functions in Veterans With Post-traumatic Peripheral Neuropathic Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Improving Functions in Veterans With Post-traumatic Peripheral Neuropathic Pain (NCT02979925), a randomized na study. The primary outcome is Evaluation of Spontaneous Pain Scores.

2. Clinical Question

The study was intended to evaluate transcutaneous magnetic stimulation as a non-contact, non-invasive approach in veterans with post-traumatic peripheral neuropathic pain, with the broader aim of informing future multi-center studies. Its registered primary measure was a self-reported spontaneous pain rating, assessed at baseline and after treatment. The outcome description states that lower scores indicate lower reported pain.

The record also lists evoked pain scores assessed by stroking and Von Frey as secondary outcomes. Those measures address responses to evoked stimuli, whereas the primary measure concerns spontaneous pain. The record does not report results for these secondary outcomes either. It therefore supports describing the research question and the intended measurements, but not drawing a conclusion about the relative pain scores or changes between the active and sham groups.

3. Trial Design

This was a randomized, double-masked, parallel-group trial with active transcutaneous magnetic stimulation and sham transcutaneous magnetic stimulation as the assigned interventions. The registry record lists an enrollment of 57 and the status as completed. The study start is recorded as 2016-11-01, and primary completion as 2019-09-30. The phase is listed as NA.

In the active arm, stimulation was applied at the target site of nerve damage or injury. In the sham arm, the parameters were described as the same as active treatment, but the subject was shielded from the coil's magnetic field. The record does not describe the randomization sequence, allocation concealment, or which people were masked. It identifies the study as double-masked but does not specify the masked roles, so further detail about how masking was maintained cannot be inferred.

The primary outcome was spontaneous pain scores, measured at baseline, one week post treatment, and four weeks post treatment. The listed secondary outcomes were evoked pain scores assessed by stroking and Von Frey. The registry record identifies three outcome measures and three analyses, but does not provide enough detail to reconstruct the analysis plan or determine how each measure and time point was handled.

The adverse-event entries list 28 participants at risk in the active group and 23 in the sham group. These group counts do not account for the full enrollment figure, and the registry record does not explain the difference. It does not report participant flow, reasons for any missing outcome data, or the populations included in the outcome analyses. Those omissions limit how fully the conduct and analysis of the trial can be assessed 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.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Evaluation of Spontaneous Pain Scores, measured over Assessed during each of the subject's baseline visit, 1 week post treatment visit, and 4 weeks post treatment visit..

The primary endpoint is titled “Evaluation of Spontaneous Pain Scores.” It uses a Mechanical Visual Analog Scale, described as a sliding algometer. The scale is anchored at “no pain sensation” and “the most intense pain sensation imaginable.” The location of the red bar is read on a scale from 0 to 100; a lower score represents less reported pain. The registry record describes the outcome as a mean with standard deviation.

A spontaneous pain rating is intended to capture pain as experienced without requiring a particular stimulus to evoke it. The record describes an assessment at baseline and at the post-treatment visits, allowing the registered outcome to address pain ratings over time. The separate secondary outcomes assess evoked pain using stroking and Von Frey, so they represent different kinds of pain responses rather than another label for the primary measure.

For interpretation, the scale’s direction matters: lower values indicate lower pain ratings. However, the registry record does not report the mean scores, standard deviations, or group comparisons for the primary endpoint. It therefore does not establish the size, direction, or precision of any difference in spontaneous pain scores between the active and sham groups.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure summarized in the registry record as a mean with standard deviation. A mean describes the central value of a set of scores, while a standard deviation describes how dispersed individual scores are around that mean. These quantities answer different questions: the mean describes the average score, and the standard deviation describes variation among participants. Neither quantity is reported for the primary outcome in the registry record, so there is no numerical summary to interpret.

What a group comparison would mean

In a randomized parallel-group study, an outcome comparison can describe how the recorded scores differ between participants assigned to active stimulation and those assigned to sham stimulation. For a continuous outcome, an estimate of the difference would ordinarily be interpreted in the units of the outcome scale. The scale description gives the direction: lower values indicate lower reported pain. But the registry record does not report a group difference or the underlying scores, so neither its direction nor its size can be stated.

A confidence interval, in general, expresses uncertainty around an estimated effect under the assumptions of the analysis. A narrower interval indicates greater precision than a wider interval, while an interval spanning a range of effects can indicate that the data are compatible with more than one magnitude or direction. The registry record does not report a confidence interval for the primary outcome. No statement about the precision of an estimated treatment difference can therefore be made.

A p-value, in general, describes how compatible the observed data are with a specified null model, conditional on the analysis assumptions. It is not a measure of effect size, and it does not indicate the probability that a treatment works. The registry record does not report a p-value for the primary outcome comparison. It also does not report the test or model used, so the statistical basis for a primary-outcome inference is not available.

Repeated assessments and outcome structure

The primary outcome was assessed at baseline, one week post treatment, and four weeks post treatment. Repeated measurements from the same participant are related rather than independent observations. In general, an analysis of repeated assessments must account for that within-person relationship or define a particular visit or change measure as the comparison of interest. The registry record does not describe which approach was used. It explicitly notes that the primary outcome has several categories or time points and is not reduced to one comparison. This means no single visit should be assumed to be the sole basis of the registered result.

The record describes the primary measure as a mean and standard deviation, but that alone does not identify the statistical model. It does not state whether the comparison used raw scores, change from baseline, a model adjusting for baseline, or another approach. It does not report whether the analysis accounted for repeated assessments. These details matter because different analysis choices can target different estimands and can use the available measurements differently. They are not reported in the registry record and should not be guessed.

Randomization, masking, and interpretation

Randomization assigns participants to groups by a chance-based process and is intended to support a fair comparison of groups. The registry record identifies the trial as randomized, but does not describe sequence generation or allocation concealment. Double masking is also recorded. The active and sham intervention descriptions indicate that the sham used the same parameters while shielding the subject from the magnetic field. The record does not explain which study roles were masked or how masking was assessed. These omissions do not change the registered design labels, but limit assessment of how the design was implemented.

The registry record gives an enrollment of 57, but enrollment is not automatically the denominator for every outcome analysis. Participants may have incomplete assessments or may not be included in a particular analysis, but no such reasons should be assumed. The record does not report outcome-specific analysis counts or missing-data methods. As a result, it is not possible to establish whether all randomized participants contributed to each registered outcome or how incomplete measurements were handled.

Planning illustrations and observed evidence

A planning illustration based on an observed effect is a hypothetical calculation about the sample size that might be needed to detect an effect under stated assumptions. The registry record describes an illustration using a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of the observed effect. Such an illustration is not a report of the trial’s original sample-size justification and is not observed power. The record does not report the protocol’s sample-size rationale, and no numerical planning estimates are available in the registry record.

In general, planning estimates depend on assumptions about the effect to detect, variability, allocation, and the chosen error rate. They do not replace the observed outcome estimates or their uncertainty. Since the primary result values are not reported, the observed effect cannot be interpreted from the registry record, and a planning illustration cannot supply a missing treatment comparison.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome was measured at baseline, one week post treatment, and four weeks post treatment. The registry record notes that the primary outcome has several categories or time points and is not reduced to one comparison. It does not report which visit or contrast was designated as the principal inferential test, whether all visits were analyzed together, or whether any adjustment was made for multiple comparisons. The statistical plan for multiplicity is not reported in the registry record.

The record lists evoked pain scores assessed by stroking and Von Frey as secondary outcomes. It does not explain how these secondary measures related to the primary analysis, whether they were confirmatory or exploratory, or how multiple outcome tests were handled. When several outcomes or comparisons are examined, multiplicity can increase the chance of at least one apparently notable result by chance. In general, a prespecified strategy can help readers interpret a set of tests, but such a strategy is not reported.

Missing-data methods and outcome-specific analysis populations are also not reported in the registry record. The enrollment figure is 57, while the adverse-event entries list 28 and 23 participants at risk in the active and sham groups. The record does not explain that difference, and those safety counts cannot be assumed to equal the primary-outcome analysis denominators. It does not report the number of participants with measurements at each visit, reasons for missing measurements, or whether any imputation or other missing-data approach was used.

Without these details, the completeness of the outcome analyses and the handling of multiple comparisons cannot be assessed. No assumptions about the statistical plan, missingness, or analysis population are warranted from the registry record alone.

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.

The registry record lists 28 participants at risk in the active transcutaneous magnetic stimulation group and 23 in the sham group. It reports zero serious adverse events, zero other adverse events, and zero deaths in each group. The list of serious adverse event terms is empty.

These are counts in the registry’s adverse-event entries. They do not show that adverse events are impossible, nor do they give detailed information about event definitions, how events were collected, or the period during which participants were monitored. The adverse-event reporting timeframe is not reported in the registry record. The counts also do not explain why the group risk denominators do not account for the full enrollment of 57.

A zero count means no events of the specified category were recorded in these entries; it is not proof of zero underlying risk. With the details available, safety interpretation should remain descriptive and limited to the recorded counts. These entries do not provide a basis for comparing the types, timing, or severity of events beyond the categories and counts recorded.

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

The registry record describes a randomized, double-masked comparison of active and sham transcutaneous magnetic stimulation in veterans with post-traumatic peripheral neuropathic pain. It identifies spontaneous pain scores as the primary outcome and gives the assessment schedule and scale direction. It also records secondary evoked-pain measures and adverse-event counts.

What the record does not provide is the primary outcome result: there are no reported group means, standard deviations, differences, confidence intervals, or p-values in the information available. Consequently, the record cannot establish whether spontaneous pain scores differed between the groups, how large any difference was, or how precisely it was estimated. The same limitation applies to the listed secondary outcomes, whose numerical results are not reported in the registry record.

The missing outcome results should not be replaced by conclusions based on the trial being marked completed, the trial’s stated aim, or the adverse-event counts. Completion status describes the registry status, not the direction or magnitude of an outcome. Zero recorded adverse events in the listed categories do not answer the efficacy question, and they do not establish an absence of possible harms.

The study’s stated purpose was to lay a foundation for future multi-center studies. The registry record supports describing that purpose and the design, but it does not report enough statistical results to determine how the primary outcome behaved or whether the planned comparison was informative. Interpretation of treatment effects requires the outcome estimates, uncertainty measures, analysis details, and participant counts at the assessment visits. Those details are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial raises several statistical issues that are important when reading clinical research. First, a registered outcome and assessment schedule are not the same as a reported result. The record names spontaneous pain scores and specifies the scale direction, yet does not report the group scores or a comparison. Without those estimates, readers cannot evaluate either the size of an observed effect or its precision.

Second, the outcome was assessed at multiple time points. Repeated measurements can describe whether scores change over time, but their interpretation depends on the comparison chosen and how the relationship among repeated observations is handled. The registry record notes multiple time points but does not report the analysis strategy or a single comparison. That makes it especially important not to infer a result from the endpoint description alone.

Third, the relationship between enrollment and analysis denominators matters. The record lists enrollment of 57, while the adverse-event entries use group risk counts of 28 and 23. It does not explain the difference or provide outcome-specific participant counts. Clear participant flow and missing-data reporting would help readers understand who contributed to each result.

Finally, the safety entries and the primary pain endpoint answer different questions. Zero recorded events in the listed categories are descriptive safety counts, not evidence about the comparative pain outcome. Keeping design information, outcome estimates, uncertainty, and safety data distinct is essential to a careful statistical reading. Here, the design is recorded, but the numerical outcome evidence needed for the primary comparison is not reported in the registry record.

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 interpretation is that the registry record does not report numerical results for the primary spontaneous pain outcome. It therefore does not permit assessment of the group scores, their change across visits, the treatment contrast, or its statistical uncertainty. Numerical results for the listed secondary outcomes are also not reported.

The primary endpoint has repeated assessments at baseline, one week post treatment, and four weeks post treatment, but the record does not identify the comparison used for inference or the model used to analyze those measurements. It does not describe adjustments for baseline or for multiple outcomes and time points. Those analysis choices cannot be reconstructed from the outcome titles and measurement schedule.

The record lists an enrollment of 57, but does not report participant flow or outcome-specific analysis counts. The safety entries list 28 participants at risk in the active group and 23 in the sham group; the reason these figures do not account for the full enrollment is not reported in the registry record. Missing-data reasons and handling are also not reported.

Although the study is identified as randomized and double-masked, implementation details such as sequence generation, allocation concealment, and the roles that were masked are not described. The record also does not report the statistical analysis plan or the original sample-size justification. These gaps limit evaluation of both the conduct and the analysis, beyond the design features and measures explicitly recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Improving Functions in Veterans With Post-traumatic Peripheral Neuropathic Pain — NCT02979925.
• Registry record last updated 2021-07-12; status last verified 2021-06.
• Results first posted 2021-06-18.
• 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 identifies a completed, randomized, double-masked, parallel-group study of active versus sham transcutaneous magnetic stimulation for veterans with post-traumatic peripheral neuropathic pain. Enrollment is listed as 57. The study start is recorded as 2016-11-01 and primary completion as 2019-09-30; phase is listed as NA.

The primary outcome was spontaneous pain scores measured at baseline, one week post treatment, and four weeks post treatment. Secondary outcomes were evoked pain scores assessed by stroking and Von Frey. The record describes lower spontaneous pain scores as indicating lower reported pain.

Numerical outcome results and statistical comparisons are not reported in the registry record. Adverse-event entries list zero serious adverse events, zero other adverse events, and zero deaths in each group, with 28 at risk in the active group and 23 in the sham group. The reason for the difference between those risk counts and total enrollment is not reported.