Virtual Human Technology for Patients With Chronic Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Virtual Human Technology for Patients With Chronic Pain (NCT04349033), a randomized na study. The primary outcome is Pain Intensity.

2. Clinical Question

The comparison is about short-term change in a patient-reported measure, not about whether any interview changes pain for every participant. A group mean describes an average, while the uncertainty around a mean difference indicates how compatible the data are with a range of possible differences. The record also identifies attitudes and clinical outcomes as study interests and lists additional patient-reported measures. Those outcomes add context, but they do not replace the stated primary question.

3. Trial Design

The registry record describes a randomized, single-masked, parallel study of virtual human interviews for patients with chronic musculoskeletal pain. It lists the study as completed, with enrollment of 94. The recorded start date is 2021-02-10, and the primary completion date is 2021-08-01. The phase is listed as NA. Wayne State University is identified as the sponsor.

Participants were assigned to one of three behavioral interview conditions: Emotional Disclosure and Brain Education, Emotional Disclosure Only, or Pain Information Control. The first approach included discussion of stress and other emotional issues plus education about how emotions and the brain influence pain. The second included discussion of stress and other emotional issues only. The control interview concerned pain history and experience. The allocation is recorded as randomized, masking as single, and the model as parallel. The identity of the masked party and further details of allocation concealment are not reported in the registry record.

The primary outcome was mean change in pain intensity from baseline to 1-month follow-up, measured using the average of the four Brief Pain Inventory pain-intensity items: highest, lowest, average, and now. The record lists Pain Interference, Pain Stages of Change Questionnaire, Pain Catastrophizing Scale, and Emotional Distress as secondary outcomes. Posted numerical results are available for the primary outcome and three of those secondary measures. Numerical results for Emotional Distress are not reported in the registry record.

The registry record does not report the original sample-size justification, detailed interview delivery procedures, or the planned statistical analysis. It also does not explain the extent of masking or provide a participant-flow account. These omissions limit what can be concluded about implementation and analysis choices from the 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

Reasons for not completing this period:

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 Pain Intensity, measured over Change from Baseline to 1-month follow-up.

The primary endpoint is mean change in pain intensity from baseline to 1-month follow-up. It uses the average of four Brief Pain Inventory ratings: highest pain, lowest pain, average pain, and pain now. The scale ranges from 0.0 to 10.0, with higher scores indicating more severe pain. The posted group values are changes, so a negative value represents a decrease in the measured score relative to baseline; it is a change in the scale score, not a direct description of every participant’s experience.

A multi-item average can represent several aspects of reported pain intensity in a single continuous measure. An average also allows the study to compare group-level changes using means and mean differences. These features make the measure suitable for examining whether the interview groups had different average score changes at follow-up. Interpretation still depends on the scale’s meaning and on how precisely the group difference is estimated.

The Brief Pain Inventory is the named instrument in the registry record, but further details about its administration, scoring beyond the listed average, or handling of missing item responses are not reported in the registry record. Nor does the record provide a threshold for interpreting the size of a score change as important to patients. The endpoint therefore supports a comparison of reported average scores, but not a claim about the personal significance of a particular change.

7. Results Posted in the Registry

• Emotional Disclosure and Brain Education ("Educational Interview"): mean -0.21 versus -0.09 on control; difference -0.12 (95% CI -0.62 to 0.38), standardized effect d = -0.12; z-test p = 0.638.
• Emotional Disclosure Only ("Psychosocial Interview"): mean -0.56 versus -0.09 on control; difference -0.47 (95% CI -0.94 to 0.00), standardized effect d = -0.48; z-test p = 0.051.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Pain Interference

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Emotional Disclosure and Brain Education ("Educational Interview"): mean -0.82 versus -0.31 on control; difference -0.51 (95% CI -1.51 to 0.49), standardized effect d = -0.26; z-test p = 0.317.
  • Emotional Disclosure Only ("Psychosocial Interview"): mean -1.27 versus -0.31 on control; difference -0.96 (95% CI -1.90 to -0.02), standardized effect d = -0.50; z-test p = 0.046.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Emotional Disclosure and Brain Education ("Educational Interview") and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Emotional Disclosure Only ("Psychosocial Interview") than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Pain Stages of Change Questionnaire

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Emotional Disclosure and Brain Education ("Educational Interview"): mean 0.30 versus -0.30 on control; difference 0.60 (95% CI -0.09 to 1.29), standardized effect d = 0.44; z-test p = 0.090.
  • Emotional Disclosure Only ("Psychosocial Interview"): mean -0.18 versus -0.30 on control; difference 0.12 (95% CI -0.53 to 0.77), standardized effect d = 0.09; z-test p = 0.718.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Emotional Disclosure and Brain Education ("Educational Interview") and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Emotional Disclosure Only ("Psychosocial Interview") and the control. The interval gives the range of effects that remain compatible with the data.

Pain Catastrophizing Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Emotional Disclosure and Brain Education ("Educational Interview"): mean -0.19 versus -0.06 on control; difference -0.13 (95% CI -0.42 to 0.16), standardized effect d = -0.23; z-test p = 0.382.
  • Emotional Disclosure Only ("Psychosocial Interview"): mean -0.15 versus -0.06 on control; difference -0.09 (95% CI -0.37 to 0.19), standardized effect d = -0.16; z-test p = 0.525.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Emotional Disclosure and Brain Education ("Educational Interview") and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Emotional Disclosure Only ("Psychosocial Interview") and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcomes cover pain interference, stages of change, pain catastrophizing, and emotional distress. Numerical arm-level results and comparisons are posted for the first three measures; numerical results for Emotional Distress are not reported in the registry record. Across the measures with posted comparisons, the point estimates do not all point in the same direction, and the degree of uncertainty varies. The overall pattern is therefore mixed rather than a uniform shift across related outcomes.

These outcomes provide context for the primary pain-intensity comparison because they address other aspects of pain experience and responses. Their pattern does not resolve the uncertainty in the primary endpoint. A finding for one secondary measure cannot establish a result for the primary measure, and agreement or disagreement between measures does not by itself show that an interview had a particular effect. The measures may capture different constructs and have different scales and precision.

The posted secondary comparisons are unadjusted, and the registry record lists no reported analyses for them. Multiple outcomes create multiple opportunities for an apparently notable result to arise by chance. General statistical explanation: when many hypotheses are tested, the chance of at least one small p-value can increase unless the analysis plan accounts for multiplicity. The record does not report whether a multiplicity procedure was planned or applied. Accordingly, individual unadjusted secondary findings should carry less weight than a prespecified primary analysis and should be interpreted as exploratory signals rather than stand-alone confirmation.

The absence of posted numerical results for Emotional Distress also means that the full secondary-outcome pattern cannot be assessed from the registry results. No conclusion should be inferred from a listed outcome name alone. Considered together, the available secondary measures add descriptive detail, but they do not provide a substitute for the missing analysis-plan information or establish a consistent overall finding.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Pain Interference
• Pain Stages of Change Questionnaire
• Pain Catastrophizing Scale
• Emotional Distress

9. Statistical Interpretation

10. Statistical Methods Explained

The registry record presents the primary outcome as a continuous measure and reports a mean change for each interview group. A continuous score can take a range of values, rather than being limited to categories such as yes or no. The group mean summarizes the central value of the observed scores, while the reported standard error describes uncertainty in estimating that mean. A standard error is not the spread of individual scores; it reflects the precision of the estimated group mean.

The posted comparisons are mean differences between each interview group and the Pain Information Control. The sign of a mean difference depends on the order of subtraction. For the posted results, negative estimates indicate that the interview group’s mean change was lower than the control group’s mean change. Because the measure is change from baseline, this comparison concerns differences in average change, rather than differences in follow-up scores alone.

What does a confidence interval convey?

A confidence interval expresses the uncertainty around an estimated mean difference. General statistical explanation: under the assumptions of the analysis, the interval procedure is designed to produce intervals that cover the true parameter at the stated confidence level over repeated studies. A wide interval signals that the estimate is compatible with a broad range of values. An interval that includes zero does not establish that the true difference is zero; it means that zero is among the values compatible with the estimate and its uncertainty under the procedure. An interval that excludes zero is not, by itself, evidence that an effect is clinically important or free of bias.

The posted primary comparisons include unadjusted p-values. A p-value measures how unusual data at least as discrepant as the observed data would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of a difference. The registry record does not report a sponsor analysis for the primary outcome, so the posted inferential comparisons are recalculated, simple unadjusted estimates based on the posted summary statistics.

Why distinguish unadjusted and sponsor-reported results?

An unadjusted comparison considers the groups’ posted summary statistics without a reported adjustment for other variables. A sponsor analysis could use a prespecified model, covariate adjustment, or other procedures that cannot be reconstructed from summary values alone. General statistical explanation: if recalculated results conflict with a sponsor’s own analysis, the sponsor’s analysis takes precedence because it may reflect the planned analysis and fuller participant-level information. The discrepancy flag is false in this record, and no sponsor analyses are listed. The absence of a listed conflict is not proof that all analysis details are available.

Randomization is intended to support comparisons between assigned groups by reducing systematic differences at allocation. It does not automatically ensure that follow-up data are complete, that group comparisons remain unbiased after missing outcomes, or that every analysis matches the intended comparison. The registry record does not report allocation concealment, the masked party, missing-data methods, analysis populations, or covariate-adjustment plans. Those omissions make it difficult to assess these aspects of the analysis from the registry information alone.

Why can over-dispersion matter?

General statistical explanation: over-dispersion occurs when observations vary more than a statistical model assumes. It is especially relevant to count or binary outcomes when a model’s assumed variability is too small, because uncertainty can then be understated and intervals or tests may be misleading. The primary endpoint is a continuous mean score, not a count outcome. The posted summary does not provide enough information to assess the distribution of individual scores or whether a particular continuous-outcome model adequately represents them. Dispersion matters more broadly because greater variability generally makes an estimated difference less precise.

The posted arm-level summaries give the mean change and standard error. A recalculation using those summaries cannot recover participant-level patterns, assess outliers, or verify modeling assumptions. It also cannot establish whether the primary outcome was analyzed according to the original plan. The registry record does not report the trial’s detailed statistical analysis plan or interim analyses, so neither should be assumed.

Finally, statistical significance and clinical importance are different questions. General statistical explanation: a small p-value can accompany a difference too small to matter to patients, while an imprecise estimate can fail to distinguish a meaningful difference from no difference. For this endpoint, the record supplies the scale range and direction but does not report a threshold for meaningful change. Interpretation should therefore focus on the estimated group differences and their uncertainty, without assigning an unreported clinical meaning to their magnitudes.

11. Confidence Intervals and Precision

The primary estimates are not equally precise in the sense of having the same uncertainty. For Emotional Disclosure and Brain Education versus Pain Information Control, the reported mean difference is -0.12 and the confidence interval spans values on either side of zero. For Emotional Disclosure Only versus Pain Information Control, the estimated difference is -0.47 and the interval also reaches across zero, with its upper bound very close to zero. Both intervals therefore leave uncertainty about whether the underlying average difference is in the direction of the point estimate or in the opposite direction.

A confidence interval is useful because it shows a range of estimates compatible with the observed data under the calculation’s assumptions. It should be read alongside the point estimate, not as a range of individual participant outcomes. The standard errors reported for the arm-level means also describe precision of the mean estimates, not the full spread of participants’ scores. The registry record does not report participant-level distributions or additional precision measures that would show how outcomes varied within each group.

The posted comparisons use relatively small arm-level samples, and the results should be read with the uncertainty reflected in their intervals. The record does not provide a confidence level label alongside the intervals in the posted comparison details, so the interval procedure’s stated confidence level is not reported in the registry record. The interval endpoints are recalculated from posted summary statistics, rather than sponsor-reported analysis results.

Precision is not the same as validity. A narrow interval would not rule out bias from missing data, outcome measurement, or analytic choices; a wide interval does not prove that there is no difference. Here, the intervals indicate that the point estimates should not be treated as exact or definitive. Their uncertainty is especially important when interpreting comparisons across multiple outcomes, because a selected result may appear notable even when the full set of tests is considered.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures describe participants per arm for the pairwise comparisons, not total events. They are illustrations based on the observed effect and use the assumptions stated for the calculation: a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the stated fraction of the observed effect. The trial’s original sample-size assumptions are not reported in the registry record, so these illustrations should not be read as the study’s own design target.

The 80% power column describes the number of participants per arm that the planning calculation estimates would be needed to have an 80% chance of detecting the specified effect under those assumptions. The 90% power column expresses the corresponding planning target for a 90% chance. These are prospective planning quantities, not a description of what happened in the completed study. This is not observed power.

Rows for planning at 100%, 75%, and 50% of the observed effect illustrate how the required sample size changes if the target effect is smaller than the observed estimate. Smaller effects are harder to distinguish from random variation under the same assumptions, so they require more participants per arm. The figures are not guarantees that a study will reach a particular result: actual precision and findings also depend on variability, missing outcomes, analysis choices, and whether the assumed effect reflects the effect a future study aims to detect.

The corresponding curve should be read as a visual version of the same planning relationship between target effect size and participant requirements. It does not show observed enrollment or observed power. Estimates derived from an observed effect can be unstable, especially when that effect is uncertain, so the planning figures are best used as illustrations rather than as a substitute for a prospective design calculation informed by the research question.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.120; pooled standard deviation σ = 0.984.
2. n = 2 × (1.96 + 0.842)² × 0.984² / -0.120² = 1,056.1, rounded up to 1,057 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.12                      # observed difference in means
sigma <- 0.984274632266898                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4349033)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 1,057 (80% power), 1,414 (90% power)
 75% of observed effect: n per arm = 1,878 (80% power), 2,514 (90% power)
 50% of observed effect: n per arm = 4,225 (80% power), 5,656 (90% power)
power.t.test: 1057.1 
Simulated power at n = 1,057 per arm: 0.798 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary outcome and several secondary outcomes, but it does not report whether the investigators planned to adjust for multiple comparisons. With more than one outcome and more than one comparison, repeated testing can raise the chance of at least one result appearing notable by chance. General statistical explanation: multiplicity can be addressed through a prespecified hierarchy, adjustment procedure, or a clear distinction between confirmatory and exploratory analyses. The registry record does not identify such a procedure, so the posted unadjusted p-values should not be treated as if they account for testing across outcomes.

Numerical results are posted for pain intensity, pain interference, stages of change, and pain catastrophizing. Emotional Distress is listed as a secondary outcome, but numerical results are not reported in the registry record. The record also does not report whether other measured outcomes were collected but not posted, whether all planned analyses were completed, or why the available outcomes were selected for reporting. These gaps prevent a full assessment of selective outcome reporting.

Missing-data handling is not reported in the registry record. The arm-level results include group sample counts, but the record does not explain whether those counts represent all randomized participants, participants with observed follow-up data, or another analysis population. It does not report the amount or reasons for missing outcome data, any imputation method, or sensitivity analyses. Without those details, the impact of missingness on the group comparisons cannot be assessed.

The registry record also does not report an intention-to-treat or per-protocol analysis population, the planned model, covariate adjustments, or interim analyses. These are not details to infer from the randomized allocation or from the posted summary statistics. They matter because the analysis population and model can influence both the estimated difference and its uncertainty. The recalculated comparisons are simple and unadjusted; they do not fill in these missing elements of the trial’s analysis plan.

15. 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 reports zero serious adverse events in each of the three interview groups, with zero deaths reported in each group. It also reports zero other adverse events in each group. The at-risk counts shown are 29 for Emotional Disclosure and Brain Education, 34 for Emotional Disclosure Only, and 31 for Pain Information Control. These figures describe what was posted for the recorded safety categories; they are not a comparison of event risk adjusted for follow-up or other factors.

Zero reported events should be interpreted as no events recorded in the registry’s reported categories, not as proof that no unwanted experiences occurred. The record does not report how adverse events were defined, how actively they were solicited, the duration of safety monitoring, or whether all participants completed safety follow-up. It lists no serious adverse event terms. The absence of a listed term does not provide detail about other possible experiences outside the reported categories.

Safety reporting is also separate from the pain-intensity efficacy outcome. These adverse-event entries do not determine whether the interviews changed pain scores, and the outcome results do not establish safety. The posted figures are a limited registry summary and should be read in that scope.

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

The results describe average changes in patient-reported scores over the interval from baseline to 1-month follow-up. They estimate how the mean change in each emotional-disclosure interview group compared with the Pain Information Control group. They do not describe every participant’s outcome, and they do not establish that an individual’s score will move in the direction of a group average.

The primary comparisons are uncertain. One point estimate is close to zero, while the other is larger in the negative direction, but both confidence intervals include values on either side of zero. The unadjusted p-values are not a measure of clinical importance and do not tell whether a result matters to patients. The registry record gives the scale range and direction but does not report a threshold for an important change, so the posted differences cannot be classified as clinically meaningful from this information alone.

The findings also do not establish that a particular interview works or does not work. The randomized design supports a comparative question, but full assessment depends on details not reported in the registry record, including missing-data handling, the analysis population, and the planned statistical approach. The posted comparisons are recalculated from summary statistics rather than reported sponsor analyses. Their scope is therefore narrower than a complete trial analysis based on participant-level data.

The results apply to the specific interview approaches, comparator, population, outcome measure, and follow-up described in the registry record. They do not establish what would happen with other interview formats, other populations, or longer follow-up. The secondary outcomes add related information but are unadjusted, and numerical results for Emotional Distress are not reported. The balanced interpretation is that the registry reports group-level estimates with substantial uncertainty and incomplete analysis detail, not a definitive judgment about an interview’s effect or a prediction for an individual.

17. Why This Trial Matters Statistically

This study is statistically interesting because it compares distinct behavioral interview approaches using a randomized, parallel design and reports a continuous primary outcome as change from baseline. The three conditions make the comparator explicit: an interview about pain history and experience is contrasted with two approaches that include emotional disclosure, with one of those also including education about emotions, the brain, and pain. This structure raises a useful design question about how clearly the intervention components are distinguished and how the selected comparator shapes interpretation.

The posted results also illustrate why an estimate, its uncertainty, and its analysis status need to be considered together. The primary point estimates differ between the two interview comparisons, but the confidence intervals span zero. A reader who focuses only on the direction or size of a point estimate may overlook the uncertainty; a reader who focuses only on a p-value may overlook the range of differences compatible with the data. Neither approach is sufficient on its own.

The registry record makes the limitations of summary-level interpretation visible. It posts means and standard errors, while the analysis details needed to evaluate missing data, the analysis population, covariate adjustment, and multiplicity are not reported. The recalculated unadjusted comparisons can help describe the posted summaries, but they cannot reconstruct a full planned analysis or participant-level assessment.

Finally, the sample-size illustrations connect observed estimates to prospective planning while requiring careful interpretation. They are based on observed effects and stated planning assumptions, not the trial’s original design or observed power. This distinction matters when using a small study’s estimate to plan future work. A future design would need a target effect justified for the research question rather than relying mechanically on an uncertain observed estimate.

18. 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.

Several limitations are specific to what the registry record makes available. The outcome results are posted as summary means and standard errors, without participant-level data or a detailed account of the primary analysis. The comparisons therefore cannot be checked against the underlying score distributions, examined for influential observations, or recalculated using an alternative model. The registry record does not report whether baseline values were adjusted for in the analysis.

The record does not explain the masked party, allocation concealment, interview fidelity, or whether the three interview conditions were delivered and received as intended. These details are relevant when interpreting a single-masked behavioral study. The registry record also does not report the analysis population, missing outcome counts and reasons, missing-data methods, or sensitivity analyses. Consequently, the extent to which missing follow-up information could affect the estimates is unknown.

The listed secondary outcomes are broader than the numerical results posted: results for Emotional Distress are not reported in the registry record. The record does not state whether multiplicity was addressed, whether outcome reporting followed a prespecified hierarchy, or whether analyses were changed after the study began. These omissions limit confidence in treating any unadjusted secondary result as confirmatory.

Follow-up for the primary outcome is at 1-month, so the posted result does not describe longer-term patterns. The record does not report a threshold for meaningful change on the primary scale. It also does not provide details about recruitment setting or participant characteristics beyond the condition, making it difficult to assess how broadly the results may apply. These limitations do not invalidate the posted estimates, but they restrict the conclusions that can be drawn from them.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Virtual Human Technology for Patients With Chronic Pain — NCT04349033.
• Registry record last updated 2024-03-12; status last verified 2024-03.
• Results first posted 2024-03-12.
• 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.

22. Record Summary

The registry record describes a completed randomized, single-masked, parallel study sponsored by Wayne State University, with enrollment of 94 and patients with chronic musculoskeletal pain. The recorded study start date is 2021-02-10, and the primary completion date is 2021-08-01. The three behavioral conditions were Emotional Disclosure and Brain Education, Emotional Disclosure Only, and Pain Information Control.

The primary outcome was mean change in Brief Pain Inventory pain intensity from baseline to 1-month follow-up. The posted comparisons with the control group are unadjusted recalculations from summary statistics, with confidence intervals that include zero. The registry record lists secondary measures, but numerical results for Emotional Distress are not reported. It does not report the detailed analysis plan, missing-data approach, analysis populations, or multiplicity procedures.

Overall, the posted results provide estimates of average change but leave uncertainty about the primary group differences. They should be interpreted as registry-level summary evidence rather than a complete account of the study’s planned and conducted analyses.