Telehealth Pain Self-Management for Employed Adults: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Telehealth Pain Self-Management for Employed Adults (NCT04248725), a randomized na study. The primary outcome is Change in Pain Interference.

2. Clinical Question

3. Trial Design

This was a randomized, single-masked, parallel-group trial. The registry lists University of Washington as the sponsor and records planned enrollment of 220. The trial status is completed, with a start date of 2020-03-02 and primary completion date of 2023-09-30. The record does not identify who was masked, or describe how masking was maintained.

Participants were assigned to E-TIPS or usual care. E-TIPS was a behavioral intervention delivered by telephone; usual care was described as standard care on a waitlist. The waitlist group was offered E-TIPS after the final 6-month follow-up outcome assessment. The intervention description in the registry record is incomplete, so additional details about its delivery are not reported in the registry record.

The primary outcome timeframe was baseline (week 0) and 12 weeks (post-treatment). The brief summary also says outcomes were assessed at baseline, mid-treatment, post-treatment, and 6-month follow-up. The registry describes the primary endpoint specifically at baseline and post-treatment; a separate primary analysis at the later follow-up is not reported in the registry record.

The posted primary outcome has group-level results for E-TIPS and usual care, and a sponsor-reported mixed models comparison. The posted secondary outcomes are change in pain self-efficacy and change in average pain intensity. The participant counts accompanying outcome results are not the same as the planned enrollment figure; reasons for this and details of the analysis population are not reported in the registry 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.

Before assignment: Of the 220 enrolled participants, 8 were excluded prior to the baseline assessment because they were not able to be contacted for baseline completion. After 212 enrolled participants completed the baseline assessment, 10 additional participants were excluded because: we were unable to contact them for randomization (n=5), they withdrew from the study due to personal circumstances (n=3), or withdrawn by staff (n=2). A total of 202 were randomized to one of the two study arms.

Post-Treatment

Reasons for not completing this period:

6-Month Follow Up

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 Change in Pain Interference, measured over Baseline (week 0) and 12 weeks (post-treatment).

The primary endpoint was change in pain interference, expressed as a T-score from the PROMIS Pain Interference Scale-6-item. Participants reported how much pain interfered with daily life across six items. Each item is scored from 1 (not at all) to 5 (very much); the summed raw score ranges from 6 to 30 and is converted to a standard T-score. The registry states that the population mean is 50, with a standard deviation of 10, and that higher scores indicate greater self-reported pain interference.

Pain interference captures the effect of pain on functioning rather than pain intensity alone. That makes it relevant to a self-management intervention aimed at helping people manage pain in the context of employment and physical disability. A change score describes how a participant's reported score differs between the assessment times; the group comparison asks whether average change differs between E-TIPS and usual care.

The posted group mean changes were -4.0 for E-TIPS and -1.3 for usual care. Since higher scores represent greater interference, a negative change indicates a decrease in reported interference. The sponsor's mixed models analysis reports a net mean difference of -2.7 and p = 0.004. A confidence interval for that net difference is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is measured on a numeric scale, and the reported group summaries are mean changes. The sponsor describes the primary comparison as a mixed models analysis and reports a net mean difference. In general, a mixed model can account for repeated measurements and can estimate a group contrast while using information across assessment times. The specific model structure, covariates, assumptions, and handling of incomplete observations are not reported in the registry record, so the exact implementation cannot be reconstructed from the posted information.

What does a mean change describe?

A mean change is the average difference between the recorded outcome at the later assessment and the earlier assessment for a group, following the study's scoring convention. For the primary endpoint, negative values indicate lower pain-interference scores at post-treatment than at baseline. Because higher PROMIS Pain Interference T-scores indicate greater interference, a negative mean change points toward reduced reported interference within that group. The difference between groups is a separate quantity: it compares the groups' changes rather than describing either group alone.

The registry reports group mean changes and their confidence intervals, alongside a model-based between-group test. The group's interval describes uncertainty around that group's estimated mean change. It should not be treated as the uncertainty interval for the contrast between groups. In general, a confidence interval gives a range of values compatible with the data and the method's assumptions; a narrower interval indicates greater precision. The interval for the primary net difference is not reported in the registry record, limiting direct assessment of its precision.

How should the p-value be read?

In general, a p-value describes how unusual the observed data, or more extreme data, would be if the null hypothesis and the analysis assumptions were correct. The primary p-value is 0.004 for the sponsor-reported mixed models comparison. It is evidence against the null hypothesis used in that test, not a measure of effect size, not the probability that the result occurred by chance, and not a measure of clinical importance. Interpreting it alongside the estimated contrast and its uncertainty is preferable; the registry does not report a confidence interval for the primary contrast.

The record also includes unadjusted recalculations for the secondary outcomes using posted group summary statistics. These are simple comparisons of group means and are not substitutes for the sponsor's reported mixed models analyses. In general, a recalculation based on summary statistics may not match a model-based estimate if the methods use different information or assumptions. The details needed to identify the precise reasons for any difference are not reported in the registry record.

What do the planning illustrations mean?

The planning illustrations use the observed effect as a reference and show estimated participants per arm for 80% power and 90% power under stated assumptions. Those assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to a stated fraction of the observed effect. For example, the illustrations include planning for 75% of the observed effect. The values are planning illustrations, not observed power and not the trial's own sample-size justification. The registry does not report the trial's original sample-size assumptions or justification.

In general, planning calculations are sensitive to the effect size assumed: planning for a smaller effect requires more participants per arm to reach the same target power, all else being equal. These illustrations do not establish that the trial was adequately powered for its primary or secondary outcomes, and they do not describe the power actually achieved. Their assumptions may not match the trial's analysis, particularly because the sponsor reports mixed models while the illustrations are based on a normal approximation.

Why do outcome scales and directions matter?

A mean difference is meaningful only in the context of the scale and its direction. For pain interference, higher T-scores indicate greater interference, so a more negative change corresponds to a greater decrease. Pain self-efficacy is also reported as a T-score, while average pain intensity is reported in units on a scale. The registry does not provide the average-pain scale's anchors or full scoring details. Comparisons across these outcomes should therefore focus on each measure's own scale and analysis, rather than treating their numerical estimates as interchangeable.

Finally, statistical precision and practical importance are different considerations. An estimate can be statistically distinguishable from a null value without establishing that its magnitude is important to participants. The registry record does not report a threshold for interpreting clinical importance for the primary measure. The posted estimates should therefore be read as statistical evidence about group-average changes, with their reported uncertainty and the limits of the available analysis details in mind.

10. Analyses Reported by the Sponsor

The sponsor's primary analysis is a mixed models comparison reporting a net mean difference of -2.7 with p = 0.004. The registry reports group mean changes of -4.0 for E-TIPS and -1.3 for usual care, but does not give a confidence interval for the net difference. The sponsor-reported comparison is the direct inferential result for the primary endpoint; the group intervals should not be substituted for an interval around that contrast.

For secondary outcomes, the registry also contains recalculations from posted summary statistics. These are unadjusted calculations and are not the sponsor's mixed models analyses. The pain self-efficacy recalculation reports a mean difference of 4.6, while the sponsor reports 0.59 with a 95% confidence interval of 0.30 to 0.88 and p < 0.001. The registry does not explain the difference in scale or analysis details, so the two estimates should not be treated as directly interchangeable.

For average pain intensity, the recalculation reports a mean difference of -0.6 with a 95% confidence interval of -1.097 to -0.103 and an unadjusted p-value of 0.018. The sponsor's mixed models result is -0.32, with a 95% confidence interval of -0.61 to -0.03 and p = 0.29. The difference between those p-values underscores that the recalculation is not a replacement for the sponsor's analysis. The registry does not report enough detail to explain the discrepancy between the estimates and tests.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and two secondary outcomes. Testing several outcomes raises a multiplicity question: if each is assessed separately, the chance of at least one apparently positive result can increase. In general, a prespecified testing order or statistical adjustment can help control that issue. Whether the trial used either approach is not reported in the registry record. The posted secondary p-values should therefore be read as individual results, not as evidence that a family-wide error rate was controlled.

The record identifies the primary comparison as a mixed models analysis but does not describe its missing-data method, analysis population, or rules for including participants in each model. It also does not report the number of missing observations at each assessment, reasons for missingness, or whether imputation was used. These details matter because incomplete outcome data can affect estimates if missingness is related to participants' outcomes or treatment assignment.

The registry's planned enrollment is 220, while the primary outcome summaries give group counts of 102 for E-TIPS and 100 for usual care. The record does not explain the relationship between planned enrollment and the counts used for those summaries, including whether all randomized participants contributed outcome data. The listed group counts should not be assumed to define the analysis population without further information.

Although the brief summary describes outcome assessment at baseline, mid-treatment, post-treatment, and 6-month follow-up, the primary result is reported for baseline and 12 weeks (post-treatment). The record does not explain how repeated measurements were incorporated into the primary model or how follow-up data were handled. Interim analyses and any stopping rules are not reported in the registry record. These omissions limit assessment of the analysis plan and of how complete follow-up may have influenced the posted estimates.

12. 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

Serious events with the highest arm-level rate: strained muscle (1.0%).

The registry reports serious adverse events for the two groups separately. For E-TIPS, one serious adverse event was recorded among 102 participants at risk; the listed serious event term is strained muscle, with a reported percentage of 1.0%. For usual care, no serious adverse events were recorded among 100 participants at risk. No other adverse events were recorded in either group, and no deaths were recorded in either group.

These figures are descriptive counts from the registry record. They do not establish that an event was caused by the intervention, and the record does not report an assessment of relatedness, severity beyond the serious-event classification, or timing. The absence of recorded non-serious events or deaths should not be interpreted as proof that no such events occurred outside the record's reporting framework.

Rare-event summaries are difficult to compare precisely, especially when event counts are small. The registry does not provide a statistical comparison of adverse-event rates or further detail about event collection and attribution. These data therefore describe the serious adverse events posted for the trial but do not, by themselves, establish a comparative safety profile.

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

The primary result indicates that, in the sponsor's mixed models analysis, the average change in pain interference differed between the E-TIPS and usual-care groups from baseline to post-treatment. The reported net mean difference is -2.7, with p = 0.004. Given that higher PROMIS Pain Interference T-scores indicate greater interference, the negative contrast is in the direction of a greater reduction for E-TIPS.

This is a group-level result. It does not mean that every participant had a reduction in pain interference, or that any particular participant would experience the average change. The group mean summarizes variation in individual outcomes. The registry does not report the distribution of individual changes, the proportion of participants with improvement, or a threshold for a clinically important change in this population.

The result also does not establish that E-TIPS changed pain intensity, self-efficacy, or other outcomes to the same degree as pain interference. Those are separate measures, and their sponsor-reported analyses differ in the strength of evidence. Nor does the primary result establish persistence at 6-month follow-up, because the posted primary comparison is for the 12-week post-treatment assessment.

The randomized design supports a comparison of assigned groups, but the registry record does not provide all information needed to assess the details of implementation, missing data, analysis populations, or multiplicity. The estimate should be understood in light of those reporting limits. It is evidence from this trial and its stated analysis, not a guarantee of results in other populations or settings, and it does not establish the intervention's practical importance without an appropriate clinical threshold.

14. Why This Trial Matters Statistically

This trial addresses an outcome that differs from pain intensity alone: pain interference, or the extent to which pain affects daily activities. That distinction is statistically important because an intervention may be evaluated against several related but nonidentical outcomes. A clear primary endpoint helps identify the main comparison, while separate secondary outcomes can describe additional dimensions of participants' experiences.

The posted result also illustrates why the between-group estimate matters more than considering each group's change in isolation. Both groups' mean pain-interference scores decreased, but the clinical question is whether their changes differed. The sponsor's mixed models analysis directly addresses that contrast. Its estimate and p-value should be interpreted alongside the limits of the reported uncertainty: a confidence interval for the primary net difference is not reported in the registry record.

The record further demonstrates why analysis method and outcome reporting need to be distinguished. The sponsor reports mixed models analyses, whereas the secondary recalculations use posted summary statistics. Those approaches need not produce matching estimates or p-values. The recalculations can offer a simple descriptive comparison, but they do not reproduce the sponsor's full model or reveal its assumptions.

Finally, the trial raises common interpretive questions about multiple outcomes, missing data, and follow-up. The registry record does not report the multiplicity strategy, missing-data handling, or full analysis populations. Those are not minor technical details: they shape how confidently a reader can interpret a set of results and how far the findings can be generalized. Reporting them alongside estimates and uncertainty would make the statistical evidence easier to assess.

15. 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.

Important design and analysis details are not reported in the registry record. The record identifies the trial as single-masked but does not say who was masked or how masking was maintained. The specific mixed models structure, adjustment variables, analysis population, and handling of missing outcomes are also not described. Without those details, the primary analysis cannot be independently reconstructed from the registry entry.

The primary net difference has no reported confidence interval, limiting direct assessment of its precision. Group-level confidence intervals are available, but they describe each group's change rather than the between-group contrast. The registry also does not report a threshold for a clinically important change in pain interference, so the practical importance of the estimated difference cannot be judged from the reported statistical result alone.

The record does not explain how planned enrollment relates to the group counts shown with the outcome summaries, or whether those counts represent all randomized participants or the analysis population. It does not report missingness by assessment, reasons for incomplete follow-up, or how outcomes at the described mid-treatment and 6-month assessments were handled in the primary analysis.

Multiplicity procedures are not reported for the secondary outcomes, and the registry does not identify whether they were intended as confirmatory or exploratory. The sponsor's secondary mixed models results also differ from the unadjusted recalculations, with no further detail to explain the differences. These limitations do not erase the posted results, but they constrain interpretation of precision, robustness, and the relationship among the outcome findings.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Telehealth Pain Self-Management for Employed Adults — NCT04248725.
• Registry record last updated 2025-01-24; status last verified 2024-12.
• Results first posted 2025-01-24.
• 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.

19. Record Summary

The registry describes a completed, randomized, single-masked, parallel-group trial of telephone-delivered E-TIPS compared with usual care on a waitlist in employed adults with physical disabilities and chronic pain. Planned enrollment was 220. The primary endpoint was change in PROMIS Pain Interference T-score from baseline to 12 weeks.

The sponsor's mixed models analysis reports a primary net mean difference of -2.7 and p = 0.004. The posted group means show a larger reduction in pain interference for E-TIPS than for usual care. A confidence interval for the primary net difference is not reported in the registry record. Two secondary outcomes are posted, but multiplicity procedures, missing-data handling, and detailed analysis-population information are not reported in the registry record.