Telephone-Delivered Cognitive Behavior Therapy for Chronic Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Telephone-Delivered Cognitive Behavior Therapy for Chronic Pain (NCT00371267), a randomized na study. The primary outcome is Short Form-12 Physical Health.

2. Clinical Question

The study was randomized, parallel-group, and unmasked. Its stated purpose was to determine whether telephone-delivered cognitive behavior therapy is effective in the treatment of chronic pain. The registry record does not report enough detail to determine whether the reported comparison was the sole basis for the study's conclusions or how the investigators planned to interpret the primary endpoint.

3. Trial Design

This was a randomized, parallel-group clinical trial comparing telephone-delivered cognitive behavior therapy with telephone-delivered patient education. The record lists no masking. The sponsor was the US Department of Veterans Affairs, and the study status is completed. The registry dates list a start of 2006-10 and primary completion of 2010-08. The phase is recorded as NA.

The study summary describes a two-arm trial involving 98 individuals aged 55 years and older with chronic pain. Participants were recruited through a primary care clinic at the VA Medical Center in San Francisco and affiliated VA Community-based Outpatient Clinics in Santa Rosa, San Bruno, Ukiah, and Eureka. Separately, the registry enrollment field lists 101. The registry record does not explain the difference between these two counts, so they should be understood as differently reported figures rather than reconciled by assumption.

The posted primary outcome is Short Form-12 Physical Health at 46 weeks. The reported arm summaries include 48 participants in the telephone CBT group and 50 in the telephone patient education group. The registry record does not report how the analysis population was defined, whether all randomized participants contributed data to this endpoint, or how missing outcome measurements were handled. It also does not report the original sample-size justification, the planned statistical analysis in sufficient detail, or whether interim analyses were conducted.

Three secondary outcomes are posted: the Beck Depression Inventory (BDI)-2 Total Score, Pain Behavior Checklist Total Score, and Pain Intensity Rating, each at 46 weeks. The record identifies additional outcome measures, but detailed interpretation is limited to the primary result and the three secondary outcomes with posted results.

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

Analysis population for the primary outcome, as defined in the registry: Veterans with chronic pain

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 Short Form-12 Physical Health, measured over 46 weeks.

The primary endpoint is Short Form-12 Physical Health, reported as a mean score in units on a scale at 46 weeks. The description says it measures physical functioning in daily living and health-related quality of life. Its stated range is 0-100, and higher scores indicate higher functioning. The score is the sum of weighted subscale scores.

A continuous score can retain information about the level of functioning across participants rather than reducing each person to a simple category. Comparing group means gives a concise description of the average scores in the two randomized groups. In this trial, the posted mean is 44.0 for telephone CBT and 41.0 for telephone patient education. The recalculated unadjusted mean difference is -3.0 units when expressed as patient education minus CBT.

The endpoint is relevant to the stated clinical question because it concerns physical functioning and health-related quality of life in veterans with chronic pain. It is not itself a direct measure of pain intensity: Pain Intensity Rating is listed separately as a secondary outcome. The registry record does not report the basis for selecting this endpoint as primary, the scale's measurement properties in this trial, or a threshold for interpreting a difference as important to participants. The posted score therefore describes the measured outcome; it does not by itself establish the clinical importance of the observed difference.

7. Results Posted in the Registry

• Arm 2: Telephone Patient Education: mean 41.00 versus 44.00 on control; difference -3.00 (95% CI -6.56 to 0.56), standardized effect d = -0.33; z-test p = 0.099.

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.

Beck Depression Inventory (BDI)-2 Total Score

• 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 deviations.
• Result:
  • Arm 2: Telephone Patient Education: mean 17.00 versus 16.00 on control; difference 1.00 (95% CI -3.17 to 5.17), standardized effect d = 0.10; z-test p = 0.638.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Arm 2: Telephone Patient Education and the control. The interval gives the range of effects that remain compatible with the data.

Pain Behavior Checklist Total Score

• 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 deviations.
• Result:
  • Arm 2: Telephone Patient Education: mean 2.40 versus 2.30 on control; difference 0.10 (95% CI -0.41 to 0.61), standardized effect d = 0.08; z-test p = 0.703.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Arm 2: Telephone Patient Education and the control. The interval gives the range of effects that remain compatible with the data.

Pain Intensity Rating

• 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 deviations.
• Result:
  • Arm 2: Telephone Patient Education: mean 3.40 versus 3.60 on control; difference -0.20 (95% CI -0.71 to 0.31), standardized effect d = -0.15; z-test p = 0.446.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Arm 2: Telephone Patient Education and the control. The interval gives the range of effects that remain compatible with the data.

The three posted secondary outcomes cover depression symptoms, pain behavior, and pain intensity. Taken together, their recalculated mean differences are small relative to the uncertainty intervals reported for each comparison, and each interval includes zero. The pattern does not establish a clear separation between the randomized groups across these additional measures. The registry also reports Mixed Models Analysis p-values for the secondary outcomes, but model estimates and confidence intervals are not reported in the registry record.

These outcomes are related to the study's chronic-pain focus but measure different aspects of participants' experience. They therefore provide context rather than a second measurement of the primary physical-health endpoint. Their overall pattern does not materially resolve the uncertainty around the primary comparison. The registry record does not report a prespecified hierarchy linking these secondary outcomes to the primary question, nor does it state how they were intended to influence the main conclusion.

Unadjusted secondary results carry less weight because multiple outcomes create more opportunities for an apparently notable result when each is examined independently. General statistical explanation: a multiplicity adjustment or a prespecified testing sequence can help control the interpretation of repeated statistical tests. Whether either approach was used is not reported in the registry record. Without that information, individual secondary p-values should not be treated as definitive tests or as independent confirmation of the primary result.

The secondary outcomes can still be informative descriptively. Their arm means show what was recorded at 46 weeks, and their intervals convey the uncertainty in the unadjusted comparisons. However, the posted results do not support a firm conclusion that one telephone approach consistently produced better results across these domains. The missing model estimates and the unreported multiplicity plan further limit formal comparisons based on the sponsor's analyses.

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

• Beck Depression Inventory (BDI)-2 Total Score
• Pain Behavior Checklist Total Score
• Pain Intensity Rating

9. Statistical Interpretation

10. Statistical Methods Explained

What does the mean difference represent?

A mean is the arithmetic average of the recorded scores in a group. For this primary endpoint, the registry lists a mean of 44.0 for telephone CBT and 41.0 for telephone patient education, with a standard deviation of 9.0 in each group. The recalculated mean difference is defined as the patient education mean minus the CBT mean, giving -3.0 units. With this direction of subtraction, a negative estimate means the posted average is lower in the patient education arm. The sign is a convention for expressing the contrast; reversing the subtraction would reverse the sign but not the underlying comparison.

The mean difference is an unadjusted comparison calculated from the posted group summaries. It does not account for other participant characteristics, repeated measurements, or any model structure. The registry's own reported analysis uses Mixed Models Analysis, but the estimate and model details are not reported in the registry record. Therefore, the unadjusted calculation should not be presented as though it reproduces that model.

Why report standard deviations?

The standard deviation describes how dispersed individual scores are around a group mean. It is not the same as the standard error, which describes uncertainty in an estimated mean. In this trial, the primary endpoint's standard deviation is 9.0 in both arms. The recalculation uses the reported group sizes and standard deviations to estimate the uncertainty around the difference in means. A group mean alone would not convey how variable the individual scores are, and a difference in means without a measure of uncertainty would not show how precisely that difference has been estimated.

General statistical explanation: when observations vary substantially within groups, a mean difference can be less precisely estimated than when observations are more tightly clustered, all else being equal. The standard deviation helps describe this within-group variation. It should not be read as a confidence interval for the treatment difference.

How should the confidence interval be read?

The recalculated 95% confidence interval for the primary mean difference is -6.564 to 0.565 units. A confidence interval describes the precision of an estimate under the assumptions of the calculation. In general, intervals that span a wider range indicate less precise estimates than narrower intervals. Here, the interval includes zero, which means the posted summary statistics do not rule out a zero mean difference under this calculation. It also includes values on either side of zero, so the direction of the underlying difference remains uncertain from the interval alone.

The confidence interval is tied to the unadjusted summary-statistic calculation. It is not the confidence interval from the sponsor's mixed model; that model interval is not reported in the registry record. The registry does not report enough analytic detail to assess how the model handled the outcome over time, missing observations, or other features of the data.

What does the p-value add?

The unadjusted p-value for the primary comparison is 0.099. A p-value describes how incompatible the observed data are with a specified null model, assuming that model and the calculation's assumptions are appropriate. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference. It should be read alongside the estimated difference and its confidence interval, not as a stand-alone judgment.

The registry's primary Mixed Models Analysis reports p <0.27, but provides no estimate or confidence interval for that analysis. The different methods can yield different results because they may use different modeling assumptions and data structures. The registry record does not give enough information to identify the reason for the difference or to reconstruct the mixed-model result. The recalculation is explicitly an unadjusted analysis from posted summary statistics; the sponsor's analysis remains a separate reported result.

What is the role of the secondary outcomes?

The registry posts continuous secondary measures for depression symptoms, pain behavior, and pain intensity, all at 46 weeks. Each is summarized by arm mean and standard deviation, and each has a recalculated unadjusted mean difference and confidence interval. The reported sponsor analyses use Mixed Models Analysis, with p-values but without model estimates or confidence intervals. These outcomes help characterize the pattern across measured domains, but they do not replace the primary endpoint.

General statistical explanation: when a study evaluates multiple outcomes, the chance of obtaining an apparently unusual result somewhere among them can increase if each is considered separately. Adjustments or a prespecified hierarchy can address some multiplicity concerns, but the registry record does not report such a procedure. Consequently, secondary findings should be interpreted as supporting context rather than as independent confirmation of a treatment effect.

What cannot be determined from the registry record?

The record does not report the original statistical analysis plan in enough detail to establish the intended model specification, handling of missing data, analysis population, or multiplicity strategy. It also does not report the original sample-size justification, interim analysis procedures, or a clinical-importance threshold for the primary score. Those omissions limit the ability to judge whether the posted results match the investigators' original plan. They do not change what the displayed summary statistics say, but they constrain how far those results can be interpreted.

11. Confidence Intervals and Precision

The recalculated primary mean difference is -3.0 units, with a 95% confidence interval from -6.564 to 0.565. The interval is the main guide to precision: it gives a range of values consistent with the unadjusted data and calculation, rather than a single certain value. Because the interval includes zero, the summary statistics do not determine whether the population mean difference is positive, negative, or zero.

The group standard deviations are 9.0 in both arms. The confidence interval is not a statement that a specified proportion of individual participants' scores fall within those limits; it concerns uncertainty about the group mean difference. Nor does it provide a clinical-importance threshold. The registry record does not report what size of difference participants or clinicians would consider meaningful, so the interval cannot be classified as excluding or including a clinically important effect based on a stated threshold.

The sponsor's Mixed Models Analysis reports p <0.27, but its estimated effect and confidence interval are not reported in the registry record. The recalculated interval is therefore not the model-based interval and should not be attributed to the sponsor's analysis. Differences in analysis method can affect estimates and uncertainty, but the absent model details do not allow the reason or magnitude of any such effect to be determined.

Confidence intervals are useful because they combine information about the estimated effect and its uncertainty. They do not remove uncertainty about study design, missing data, outcome measurement, or generalizability. In this trial, the primary interval is compatible with a range of possible mean differences, and the registry does not provide the additional analysis detail needed to narrow interpretation beyond that unadjusted comparison.

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 are participants per arm, not total events. They are illustrations computed from the observed effect, rather than the trial's original design assumptions. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set at the stated fraction of the observed effect: 100%, 75%, or 50%.

The 80% power column describes the planned number of participants per arm for a design with an 80% chance of detecting the specified effect under those assumptions, if that effect is real and the assumptions hold. The 90% power column describes the corresponding planning target for a 90% chance. These are design calculations, not guarantees about results. The figures are not observed power.

For the primary outcome, the planning illustration using 100% of the observed effect gives 142 participants per arm for 80% power and 190 participants per arm for 90% power. When the target is 75% of the observed effect, the corresponding figures are 252 and 337 participants per arm. At 50% of the observed effect, they are 566 and 757 participants per arm. The same planning logic applies to the secondary outcomes, whose estimates and variability lead to different illustrative sample sizes.

Smaller effects are harder to distinguish from random variation, so detecting a smaller target effect generally requires more participants. These planning calculations use the observed effect as their starting point; the observed effect itself is uncertain, particularly given the width of its confidence interval. The registry record does not report the trial's original sample-size justification or its original design assumptions, so these illustrations should not be treated as a description of the trial's actual planning.

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 = -3.000; pooled standard deviation σ = 9.000.
2. n = 2 × (1.96 + 0.842)² × 9.000² / -3.000² = 141.3, rounded up to 142 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 <- -3                      # observed difference in means
sigma <- 9                     # 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(371267)
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 = 142 (80% power), 190 (90% power)
 75% of observed effect: n per arm = 252 (80% power), 337 (90% power)
 50% of observed effect: n per arm = 566 (80% power), 757 (90% power)
power.t.test: 142.2 
Simulated power at n = 142 per arm: 0.801 (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. Analyses Reported by the Sponsor

The registry reports a Mixed Models Analysis for the primary comparison, with p <0.27. It does not report the model's effect estimate, confidence interval, or enough detail about model specification and data handling to reproduce the analysis. The recalculated result is a simple unadjusted comparison derived from the posted arm means, standard deviations, and group sizes: the mean difference is -3.0 units, with a 95% confidence interval from -6.564 to 0.565 and an unadjusted p-value of 0.099.

These are different analyses and should not be treated as interchangeable. The recalculation does not adjust for other variables or model repeated observations, and the registry record does not show whether or how the sponsor's model did so. As a result, the sponsor-reported p-value cannot be used to recover the missing model estimate or its precision. Conversely, the unadjusted confidence interval should not be described as the mixed-model interval.

The registry record does not report an explanation for the difference between the sponsor's reported p-value and the recalculated p-value. Because the record does not establish that the two analyses use the same estimand, assumptions, or analysis population, the difference should not be interpreted as an error or as evidence about why the results differ. The sponsor's analysis is the trial's reported analysis; the recalculation is a transparent, unadjusted reading of the posted summaries and provides a complementary view of effect size and precision.

15. Multiplicity, Missing Data and Analysis Populations

The registry reports one primary outcome and three secondary outcomes with results. Considering more than one outcome raises a multiplicity issue: repeated statistical testing can make an apparently unusual result more likely to arise by chance somewhere among the set of tests. This is a general statistical concern, not evidence that any particular result in this trial is spurious.

The registry record does not report whether the investigators adjusted secondary analyses for multiplicity, used a prespecified hierarchy, or treated the secondary outcomes as exploratory. It also does not report the complete analysis plan needed to establish how the primary and secondary hypotheses were ordered or interpreted. The unadjusted recalculated p-values should therefore be understood as individual comparisons, not as multiplicity-controlled conclusions. The reported mixed-model p-values are also not accompanied by a stated multiplicity procedure.

Missing-data handling and analysis populations are similarly not reported in the registry record. The posted endpoint summaries give arm-specific group sizes, means, and standard deviations, but do not explain whether these group sizes refer to everyone randomized, everyone with an available 46-week measure, or a defined analysis subset. The record does not describe imputation, model-based handling of missing measurements, exclusions, or sensitivity analyses. It is therefore not possible to assess from the registry record whether missing outcome data could have affected the comparisons.

The record also does not report interim analyses or the original statistical plan. These omissions matter because interpretation depends not only on the final estimates but also on which analyses were planned and how incomplete observations and multiple outcomes were handled. The posted summaries remain useful descriptions of the recorded results, but these missing details limit claims about confirmatory evidence and the robustness of the findings.

16. 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.

The registry lists 0 serious adverse events and 0 other adverse events in the telephone CBT group, with 48 at risk in each category. It lists 0 serious adverse events and 0 other adverse events in the telephone patient education group, with 50 at risk in each category. No serious-event terms are listed.

These entries describe what is recorded in the adverse-event fields; they should not be read as proof that no unwanted events occurred outside the reporting definitions or collection procedures used for the trial. The registry record does not provide additional detail about event ascertainment, duration of safety follow-up, or how adverse events were defined. The death fields are not populated with a count, so deaths are not reported in the registry record; they should not be interpreted as zero deaths.

The safety figures are separate from the primary and secondary outcome comparisons. They do not establish the safety of either intervention beyond the information recorded for this trial, and they do not resolve the uncertainty in the physical-health result. Their interpretation is limited to the reported counts and the missing details about collection and reporting.

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

The primary result describes physical-health scores at 46 weeks among participants in two telephone-delivered approaches for chronic pain. The posted mean was 44.0 with telephone CBT and 41.0 with telephone patient education. The unadjusted mean difference, expressed as patient education minus CBT, was -3.0 units. Its 95% confidence interval, -6.564 to 0.565, includes zero, so the summary data do not establish a definite direction for the underlying mean difference.

This comparison is between CBT and patient education, not between treatment and no treatment. The study summary says the trial was designed to examine whether telephone-delivered CBT is effective, but the posted comparison alone cannot answer how either approach compares with no intervention or with other kinds of care. The result also concerns a particular endpoint: physical functioning and health-related quality of life, rather than pain intensity alone.

The registry reports a mixed-model p-value for the primary outcome but does not report the model estimate or interval. The unadjusted recalculation and the sponsor's model result therefore offer different, incomplete pieces of information. The registry record also does not report a threshold for clinical importance, so statistical estimates cannot be translated into a statement about whether a difference would matter to participants.

The findings apply to the described trial population and setting: veterans with chronic pain recruited through a VA primary care clinic and affiliated outpatient clinics, with the study summary describing individuals aged 55 years and older. They should not automatically be extended to people outside that population or setting. Random allocation supports a comparative design, but the lack of masking, unreported missing-data methods, and incomplete statistical-plan details limit the strength of conclusions that can be drawn from the registry record alone.

In short, the posted data show a lower average physical-health score in the patient education arm, but the unadjusted estimate is imprecise and its interval includes zero. This is not proof of equivalence, nor does it establish that either approach is effective or ineffective. It is a description of the recorded comparison with substantial limits on interpretation.

18. Why This Trial Matters Statistically

This trial illustrates why a group mean difference should be read together with its uncertainty. The primary estimate is expressed in scale units and has a confidence interval that includes zero. Looking only at the direction of the means would conceal that uncertainty; looking only at a p-value would conceal the estimated size and range of plausible differences.

It also shows why the registry's reported analysis and a summary-statistic recalculation need to be distinguished. The sponsor reports a mixed-model p-value but no model estimate or interval. The unadjusted calculation makes the observed scale difference and its precision explicit, while leaving the sponsor's model result intact as a separate analysis. Without the model specification and estimate, a reader cannot determine how the two analyses relate beyond the fact that they address the same comparison.

The study compares two telephone-delivered approaches, which is important for framing the estimand: the result describes their relative outcomes, not the effect of telephone delivery versus no intervention. Its secondary outcomes span related but nonidentical domains, and their interpretation is constrained by the absence of a reported multiplicity strategy. These are common distinctions in clinical trial reading, where the comparator, endpoint, and analysis plan all shape what a result can support.

Finally, the registry contains different participant counts in its enrollment field and its study summary. Identifying that discrepancy without silently reconciling it is part of sound evidence interpretation. The missing information about analysis populations and missing data further reinforces that numerical precision is only one aspect of evidence quality. A careful reading attends to both the calculations that can be made and the details the record does not report.

19. 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 registry's enrollment field lists 101, while the study summary describes a two-arm trial with 98 individuals. The record does not explain this difference. The arm-specific endpoint summaries list 48 participants for telephone CBT and 50 for telephone patient education, but do not clarify how those counts relate to the enrollment field or the summary count.

The trial was unmasked. The registry record does not report whether any outcome assessment or analysis procedures were designed to reduce potential effects of knowing group assignment. The study population and recruitment setting are also specific: veterans with chronic pain recruited from a VA primary care clinic and affiliated VA Community-based Outpatient Clinics, and the summary describes individuals aged 55 years and older. Generalization beyond that population and setting requires caution.

For the primary outcome, the registry reports group means and standard deviations at 46 weeks, but does not report baseline endpoint values, the number of missing measurements, reasons for missingness, or the methods used to handle missing data. The sponsor's mixed-model estimate and confidence interval are also absent. These omissions prevent a full assessment of whether the model-based result agrees in magnitude with the unadjusted recalculation.

The registry does not report the original sample-size justification, detailed analysis plan, analysis population, multiplicity procedure, interim analyses, or a clinical-importance threshold for the primary scale. It also does not provide further detail on adverse-event definitions or ascertainment. These are limitations of what can be concluded from the registry record; they do not establish that the trial investigators lacked such plans or procedures.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Telephone-Delivered Cognitive Behavior Therapy for Chronic Pain — NCT00371267.
• Registry record last updated 2014-11-06; status last verified 2014-10.
• Results first posted 2014-11-06.
• 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.

23. Record Summary

NCT00371267 is a completed, randomized, unmasked, parallel-group trial sponsored by the US Department of Veterans Affairs. It compares telephone-delivered cognitive behavior therapy for pain management with telephone-delivered patient education regarding chronic pain management. The registry lists enrollment of 101, while the study summary describes 98 individuals aged 55 years and older; the discrepancy is not explained.

The primary outcome is Short Form-12 Physical Health at 46 weeks. The unadjusted mean difference is -3.0 units for patient education minus CBT, with a 95% confidence interval from -6.564 to 0.565. The registry reports a Mixed Models Analysis p-value of <0.27 but no model estimate or confidence interval. Three secondary outcomes are also posted, with no reported multiplicity procedure. Missing-data methods, analysis populations, and the original sample-size justification are not reported in the registry record.