Meditation-CBT for Opioid-treated Chronic Low Back Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Meditation-CBT for Opioid-treated Chronic Low Back Pain (NCT01775995), a randomized phase 1, phase 2 study. The primary outcome is Health-Related Quality of Life: Averaged Pain Severity.

2. Clinical Question

The trial also aimed to assess feasibility and outcomes beyond pain. The registry summary identifies opioid medication use as a secondary outcome and describes further interests in alcohol and drug use or misuse, stress-sensitive measures, and economic outcomes. The posted results identify Opioid Dose as a secondary outcome, but the values for those outcomes are not reported in the registry record.

The practical statistical question is whether the observed changes in the two randomized groups can be interpreted as evidence of a difference attributable to the intervention. The group-level pain changes are reported with 95% confidence intervals, but a between-group estimate and its uncertainty are not reported. The separate group results therefore describe the observed changes; they do not, by themselves, quantify the randomized comparison.

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. It lists the study as Phase 1 and Phase 2 and records enrollment of 35. The study status is completed. The sponsor is the University of Wisconsin, Madison. The recorded study start is 2013-01, and primary completion is recorded as 2013-12.

The intervention group received meditation-CBT in addition to usual care for chronic low back pain and opioid therapy management. The comparator was a wait-list control group receiving usual care for those conditions and opioid management. The registry's intervention descriptions characterize meditation-CBT as behavioral and usual care alone as the other intervention type. No details about the sequence generation, concealment of allocation, or practical steps used to assign participants are reported in the registry record.

Randomization is intended to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics. In a small trial, chance differences between groups can nevertheless remain. The absence of masking is also relevant when interpreting participant-reported outcomes such as pain: participants knew which group they were in, and the registry does not describe masking of outcome assessors.

The posted primary endpoint is averaged pain severity, expressed as change from baseline to 8 weeks. This is distinct in timing from the registry summary's stated hypothesis at 26 weeks. The summary refers to pain severity and physical function as primary outcomes in that hypothesis, while the posted primary measure described in the results is pain severity at 8 weeks. A physical-function result or a 26-week result is not reported in the registry record.

The enrollment figure describes the trial record, while the primary endpoint results are based on participants analyzed for that measure. The record states that one Meditation-CBT participant did not provide 8-week data for this measure. The displayed analyzed group sizes are 20 for Meditation-CBT and 14 for wait-list control. These counts should be read as endpoint-specific analyzed groups, not as a substitute for a full account of recruitment, allocation, and follow-up.

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:

Analysis population for the primary outcome, as defined in the registry: One Meditation-CBT participant did not provide data for this measure at 8-week follow up. Results on this measure are based on the number of participants analyzed.

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 Health-Related Quality of Life: Averaged Pain Severity, measured over baseline to 8 weeks.

The primary measure is health-related quality of life assessed through averaged pain severity. It is based on 4 responses on the Brief Pain Inventory's 0-10 numerical rating scale: pain at its worst in the last week, pain at its least in the last week, pain on average, and pain right now. A higher score represents more severe pain on this scale.

The reported endpoint is a difference score, meaning change from baseline to the 8-week measure. The registry specifies that positive values indicate increased pain and negative values indicate decreased pain. Thus, the sign of a group mean describes the direction of the average change within that group. The measure's 95% confidence interval describes uncertainty around that group mean, not directly around the difference between randomized groups.

Pain severity is used as a patient-reported indicator of symptom burden. Averaging several descriptions of pain can represent more than a single moment or pain context, while retaining a scale that is interpretable in relation to the participant's reported experience. The record does not explain why this particular measure or follow-up time was selected over alternatives.

The distinction between a group change and a treatment contrast matters. A group can improve or worsen over time for reasons that also affect the comparator, including usual care and changes unrelated to the assigned intervention. The randomized comparison is therefore the relevant basis for estimating the intervention's effect. A numerical estimate and confidence interval for that contrast are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a continuous primary outcome summarized as a mean, with a 95% confidence interval. The endpoint is change in averaged pain severity from baseline to 8 weeks. These features determine what the reported numbers represent: each mean describes the average change among participants analyzed in that group, and each interval describes uncertainty about that group's mean.

What does a group mean represent?

A mean combines individual measurements into a single summary. For a change score, each participant's follow-up measurement is interpreted relative to baseline, and the group mean summarizes those changes. The registry defines negative changes as decreased pain and positive changes as increased pain. This interpretation applies to the group mean, but it does not imply that every participant changed in the same direction. Individual-level results are not reported in the registry record.

Group means alone do not estimate the randomized treatment effect. In general, a treatment contrast compares the outcome under one assigned group with the outcome under the comparator. For this trial, the relevant contrast would be a comparison of pain change between Meditation-CBT and wait-list control. The registry record does not report that contrast, its confidence interval, or a test result. No contrast should be constructed from the posted means for this explanation.

What does a 95% confidence interval convey?

In general, a confidence interval reflects the precision of an estimate under a statistical procedure and its assumptions. Repeated use of a valid 95% confidence-interval procedure would yield intervals that cover the target value at the stated rate over repeated samples. For a reader considering a single interval, it is useful as a range of values compatible with the data and procedure, rather than as a guarantee about the true value.

The reported interval for Meditation-CBT runs from -1.1 to 0.03, and the interval for wait-list control runs from -0.3 to 1.0. Each interval includes zero. For a group change, zero corresponds to no average change under the endpoint's difference-score definition. These intervals address uncertainty about the separate group means. A confidence interval for the group contrast could have a different width and location, because its uncertainty depends on the comparison and the relevant data structure.

The registry labels the reported dispersion as a 95% confidence interval, but does not report the calculation method, the underlying standard errors, or whether any adjustment was used. It is therefore not appropriate to infer the precise analysis model from the interval label alone.

Why does randomization matter?

In general, random assignment supports a fair comparison by distributing prognostic characteristics across groups in expectation. It does not guarantee that groups are identical, particularly in a small study. The trial is listed as randomized and parallel, but details of the allocation process are not reported in the registry record. No masked design is listed. These features frame interpretation but do not substitute for a reported comparison model.

A direct comparison should account for the trial's assignment structure and should make clear whether the analysis compares follow-up values, change scores, or another estimand. An estimand is the precise treatment effect a study intends to estimate, including the population, outcome, time point, and handling of events such as missing measurements. The registry record does not provide enough analysis detail to identify a fully specified estimand or model for this result.

How should planning calculations be read?

General sample-size planning asks how many participants per arm might be needed to detect an effect under specified assumptions. The registry's planning illustration is described as being computed from the observed effect, not as the trial's original design calculation. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the target effect is described as a stated fraction of the observed effect.

Such calculations are planning illustrations, not observed power and not evidence that the current study had a particular probability of detecting an effect. Their interpretation depends on assumptions about the target effect, variability, allocation, and analysis. The original sample-size justification and the trial's own design assumptions are not reported in the registry record. Numerical planning estimates are not described in the registry record for this explanation and are not reproduced.

What statistical details are not available?

The registry lists zero analyses. A statistical analysis plan, model specification, treatment-contrast estimate, p-value, adjustment for baseline measurements, and method for handling missing outcomes are not reported in the registry record. It is also not reported whether the endpoint analysis followed an intention-to-treat principle or another analysis population. These omissions prevent a detailed assessment of the inferential procedure behind the group summaries.

General statistical interpretation should keep the estimate, its uncertainty, and the design in view together. Here, the group means and their intervals support a description of the observed 8-week changes. They do not supply the missing comparison estimate or establish the meaning of other outcomes in the trial's broader aims.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study evaluates multiple outcomes, time points, or statistical comparisons. In general, testing many hypotheses can increase the chance of obtaining at least one apparently notable result by chance. Appropriate interpretation depends on knowing which outcomes were prespecified, which comparisons were planned, and whether any adjustment or hierarchy was used. Multiplicity procedures are not reported in the registry record.

The registry lists 29 outcome measures and zero analyses. Its secondary outcomes list Opioid Dose twice, and the posted secondary-outcome count is 2. The record does not explain how the repeated label relates to distinct measurements, nor does it give numerical results for those secondary outcomes. The summary also mentions several additional areas of interest. The number of outcome measures alone does not establish how many statistical tests were performed.

For the primary pain measure, the registry states that one Meditation-CBT participant did not provide data at 8-week follow-up and that results are based on the number of participants analyzed. The group sizes shown for the analysis are 20 for Meditation-CBT and 14 for wait-list control. The missing-data handling method is not reported. It is not clear from the registry record whether any other missing measurements occurred or how they were handled.

Analysis populations are also important: an intention-to-treat analysis generally retains participants according to randomized assignment, while other approaches may include only participants with available outcome data or meeting defined criteria. Which population was used, how participants were assigned to it, and whether any sensitivity analyses addressed missingness are not reported in the registry record. The displayed group summaries should therefore be interpreted as results for the analyzed participants, as the record specifies, rather than assumed to represent a particular analysis principle.

11. Safety Results

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

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The registry reports zero serious adverse events among 21 participants at risk in the Meditation-CBT group and zero among 14 participants at risk in the wait-list control group. These are the serious-event counts recorded for the groups, not a statistical comparison of risk. No serious adverse event terms are listed.

For other adverse events, the record lists 7 affected participants among 21 at risk in the Meditation-CBT group and 0 among 14 at risk in the wait-list control group. These counts should be read with their stated group denominators and the registry's distinction between serious and other adverse events. No inferential comparison or assessment of uncertainty for these counts is reported in the registry record.

The number of deaths is recorded as null for each group, so death counts are not reported in the registry record. The adverse-event observation period, event definitions, collection procedures, and details about severity or relatedness are not reported. Consequently, the counts describe what is entered in the record but do not, by themselves, establish comparative safety or explain the clinical significance of any event.

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

The result describes average changes in self-reported pain severity from baseline to 8 weeks among participants analyzed for this measure. The Meditation-CBT group mean change was -0.5 units on a scale, while the wait-list control mean change was 0.4 units on a scale. The 95% confidence interval for each group mean includes zero. These values provide a descriptive account of the observed group changes and their uncertainty.

The posted summaries do not report a randomized between-group estimate. A reader cannot use these group summaries alone to determine the size or precision of the treatment contrast. Nor does a negative group mean establish that every participant experienced decreased pain. The registry record does not include individual participant outcomes.

The result also does not answer every question in the registry summary. The stated hypothesis concerns outcomes at 26 weeks, including pain severity and physical function, while the posted primary endpoint is measured from baseline to 8 weeks. No 26-week or physical-function result is reported in the registry record. Numerical findings for opioid dose and the other outcomes described in the summary are also not reported.

More generally, statistical uncertainty is not the same as clinical importance. A confidence interval indicates uncertainty about an estimate under a procedure; it does not say whether a change matters to patients. The registry record does not identify a threshold for a clinically important change in averaged pain severity. It also does not report a treatment-contrast interval that could be assessed against such a threshold.

These results should therefore be read as limited descriptive evidence about group-level 8-week pain changes in a small completed randomized trial. They neither establish a benefit nor establish an absence of a difference. The direct comparison, its uncertainty, and results for the broader outcomes are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial raises an important statistical distinction between change within each group and a treatment effect between groups. The posted endpoint summaries describe average baseline-to-8-week changes. The scientific question implied by randomization, however, concerns whether those changes differ between meditation-CBT plus usual care and usual care alone. Without a reported contrast and its uncertainty, the descriptive summaries cannot fully answer that comparative question.

The trial is also a reminder that a registry's summary hypothesis and its posted primary result can refer to different time points. The summary describes outcomes at 26 weeks, whereas the primary measure is defined through 8 weeks. Clear alignment among the question, endpoint, follow-up time, and analysis is essential for readers to know which claim a result can support.

Small studies can be useful for examining feasibility and generating estimates, but their estimates may be imprecise. The intervals around these group means span zero, and the record does not provide a treatment-contrast interval. Planning illustrations based on an observed effect can help explore design assumptions, but they are not observed power and do not replace the trial's original sample-size rationale, which is not reported in the registry record.

Finally, the record's broader objectives include opioid dose and other health and economic outcomes, but the numerical results for those outcomes are not reported. A careful statistical reading distinguishes what the available endpoint summaries show from what remains unanswered. That distinction matters when registry results are used to understand the evidence base or to plan future research.

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 available primary result is limited to averaged pain severity measured as change from baseline to 8 weeks. The registry summary describes hypotheses at 26 weeks and includes physical function, but results for those outcomes are not reported in the registry record. The reported time point therefore does not establish what happened at the later time described in the summary.

The registry gives group means and separate 95% confidence intervals, but no between-group estimate, confidence interval for the contrast, or p-value. Without those results, the randomized comparison cannot be assessed directly from the posted endpoint summaries. The methods used to calculate the intervals and the analysis model are not reported.

For this endpoint, one Meditation-CBT participant did not provide 8-week data. The record says the results are based on participants analyzed, but does not describe the missing-data method, the analysis population, or sensitivity analyses. The endpoint-specific analyzed groups should not be assumed to represent a particular intention-to-treat procedure.

The trial was unmasked, and pain was self-reported. Knowledge of group assignment can be relevant when interpreting subjective measures, although the registry information does not establish whether or how that knowledge affected responses. Details about allocation procedures, outcome-assessor masking, and the trial's statistical analysis plan are not reported.

The record lists 29 outcome measures and zero analyses, but does not explain the multiplicity strategy or provide numerical results for the secondary outcomes. The adverse-event record gives counts but does not report the observation period, event definitions, or a comparative statistical analysis. These limits constrain interpretation of efficacy, safety, and the broader set of stated aims.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Meditation-CBT for Opioid-treated Chronic Low Back Pain — NCT01775995.
• Registry record last updated 2016-05-16; status last verified 2016-04.
• Results first posted 2014-12-04.
• 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

NCT01775995 is a completed, randomized, parallel-group, unmasked Phase 1 and Phase 2 trial sponsored by the University of Wisconsin, Madison. It enrolled 35 and studied adults with opioid-treated chronic low back pain. The recorded start is 2013-01, and primary completion is 2013-12.

The intervention was meditation-CBT plus usual care; the comparator was wait-list control with usual care. The posted primary measure is averaged pain severity, expressed as change from baseline to 8 weeks. Mean changes were -0.5 units on a scale for Meditation-CBT and 0.4 units on a scale for wait-list control, with separate 95% confidence intervals of -1.1 to 0.03 and -0.3 to 1.0, respectively.

The registry record does not report a direct between-group estimate or its uncertainty. One Meditation-CBT participant lacked 8-week data for this measure. Numerical results for the broader outcomes described in the registry summary are not reported in the registry record.