Trial of Chronic Pain Self-Management in Clinic or Community for Low-Income Hispanics: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trial of Chronic Pain Self-Management in Clinic or Community for Low-Income Hispanics (NCT02906358), a randomized na study. The primary outcome is Five Times Sit-to-stand (5XSTS).

2. Clinical Question

The trial addresses whether the setting and delivery schedule of a pain self-management program are associated with differences in physical function as measured by repeated chair stands. Both arms received behavioral self-management programs; the contrast is between the community-based and clinic-based formats, not between a program and no program. The schedules also differ in meeting duration, frequency, and total number of meetings, so any arm contrast would concern these program packages as implemented rather than setting alone.

The record describes an intended population of low-income Hispanic patients with chronic pain and refers to opioid use in the official title and study summary. It does not report a complete eligibility definition or enough detail to determine how representative the enrolled participants were of other people with chronic pain. Enrollment was 111. The primary outcome timeframe is change from baseline at three and six months, although the registry description indicates that the primary outcome has several categories or time points and is not reduced to one comparison. Numerical estimates for the primary outcome are not reported in the registry record, so the clinical question can be described but not answered from the available outcome information.

3. Trial Design

This was a randomized, parallel-group trial, marked completed in the registry record. The enrollment was 111. The record lists single masking; further details about who was masked and how masking was implemented are not reported in the registry record. The phase is listed as not applicable. The sponsor was The University of Texas Health Science Center at San Antonio.

Participants were assigned to community-based or clinic-based pain self-management. The community program scheduled two one-hour meetings monthly for the first three months, followed by one monthly meeting for the last three months, for nine meetings in total. The clinic program scheduled individualized meetings of 30–45 minutes once monthly for six months. These are different delivery schedules as well as different settings, which matters when interpreting an arm comparison: the contrast does not isolate location while holding meeting dose and format constant.

The primary outcome was change from baseline in the Five Times Sit-to-stand measure at three and six months. The registry description also lists several secondary measures, including walking performance, functional ability, cognitive testing, pain severity and interference, perceived effort, and physical health status. The registry lists 12 outcome measures, while the detailed secondary-outcome list names eight measures. Outcome-level analysis counts are listed as zero.

The record describes a completers analysis of unadjusted changes. For selected measures at three months and all measures at six months, it identifies community-arm completers as 36, clinic-arm completers at three months as 33, and clinic-arm completers at six months as 31. These are analysis counts described in the record, not a complete account of outcome availability or reasons for missing assessments. Further details on allocation procedures, concealment, masking, and the statistical analysis plan 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: We report a completers analysis of unadjusted change in outcome measures in community and clinic arms at 3 months (for selected measures) and 6 months (for all measures), that include only completers in the participant flowchart (Community arm=36, Clinic arm 3 months=33, 6 months=31). Completers may differ by outcome if data was missing.

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 Five Times Sit-to-stand (5XSTS), measured over Change from Baseline sit-to-stand at 3 and 6 months.

The primary endpoint is the Five Times Sit-to-stand measure, recorded in seconds. Participants sit in a standard armless chair and stand up five times as quickly as possible while a researcher times the task. After a brief rest, they repeat the test, and the average of the two tests is calculated. The registry describes the endpoint as change from baseline at three and six months.

This test is a continuous measure of task completion time: lower or higher values would need to be interpreted in relation to the observed results and the analysis definition, neither of which is numerically reported in the registry record. A change score represents how a participant’s measured time at follow-up differs from their baseline time. Comparing changes between arms can describe whether the average change differed between the two program groups, but the meaning and precision of that comparison depend on the estimate, its uncertainty, the analysis population, and handling of missing observations.

General: a timed functional task can be useful because it turns performance of a defined activity into a measurable outcome. Repeating the task and averaging the two tests may reduce the influence of variation between attempts. However, measurement consistency, the clinical importance of a particular change, and the degree to which the test reflects broader daily function require evidence beyond the endpoint description. The registry record does not report a threshold for clinically important change or numerical primary-endpoint results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized parallel-group comparison and a continuous primary measure. Its stated analysis is an unadjusted comparison of change from baseline among completers. Numerical estimates and the detailed statistical plan are not reported in the registry record. The concepts below explain how to read this type of analysis in general; they should not be mistaken for methods confirmed to have been used in this trial.

What does change from baseline represent?

For each participant, a change score compares a follow-up measurement with that participant’s baseline measurement. An arm-level summary can then describe the average change among the participants included in that analysis. An arm contrast compares those summaries. The Five Times Sit-to-stand measure is recorded in seconds, and the record identifies assessments at three and six months. It does not report the numerical mean changes or the difference between arms at either assessment.

General: a change score and a follow-up score adjusted for baseline are different analysis approaches. They can yield different estimates and precision, particularly when baseline values vary. The record specifies unadjusted change and does not report a baseline-adjusted model. No covariate adjustment should therefore be assumed.

What do the mean and standard deviation describe?

The primary measure is characterized as a mean of a continuous outcome with standard deviation as the dispersion measure. A mean gives the arithmetic average of observed values in an analysis group. A standard deviation describes how spread out individual values are around that mean. It is not the uncertainty of the mean itself, and it is not a confidence interval. The registry record does not report the primary means or standard deviations.

General: individual measurements may vary substantially even when group averages are similar, and a mean can be influenced by unusually high or low observations. The distribution of the timed task, and whether the analysis checked model assumptions, are not reported in the registry record.

How should uncertainty be understood?

General: an estimated arm difference is subject to sampling variability because a trial observes a sample rather than every person in the target population. A confidence interval gives a range of values compatible with the observed data under the statistical model and its assumptions. Its width reflects precision: more uncertainty generally produces a wider interval. A point estimate without an interval can conceal substantial uncertainty, while a confidence interval does not by itself determine whether an effect matters clinically.

The registry record does not report a primary-outcome confidence interval, p-value, or standard error. The record therefore does not permit an assessment of the precision of the primary arm contrast or whether it is statistically distinguishable from no difference under a particular testing procedure.

Why does the analysis population matter?

The record describes a completers analysis and gives the arm-specific numbers included at the stated assessments: community arm 36, clinic arm at three months 33, and clinic arm at six months 31. These assessment-specific counts indicate that the analysis did not simply use all enrolled participants at every time point. General: excluding participants without observed follow-up can create bias when missingness is related to outcome values or participant characteristics. The amount and causes of missing data, the missing-data assumptions, and any sensitivity analyses are not reported in the registry record.

General: an intention-to-treat analysis usually seeks to retain participants in their randomized groups, regardless of adherence, while a completers analysis uses those with the necessary outcome data. The registry description explicitly characterizes the reported approach as a completers analysis; it does not report an intention-to-treat analysis. Nor does it provide enough detail to evaluate adherence or crossover between program formats.

What can the planning assumptions tell us?

The record describes sample-size planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The target effect is described as a stated fraction of the observed effect. These assumptions identify a planning framework, but the specific effect fraction and resulting sample-size values are not reported in the registry record.

General: such calculations ask how many participants per arm might be needed under chosen assumptions to detect a specified effect with a chosen power. They depend on the assumed effect and variability, and they are planning illustrations rather than evidence about what the trial observed. They are not a measure of observed power. The record does not report the trial’s own sample-size justification or indicate that these illustrations were the basis for its design.

How should over-dispersion and model choice be considered?

General: over-dispersion means that observed variability is greater than a statistical model expects. It can make standard errors too small and confidence intervals too narrow if the model does not allow for the extra variation. This concept is especially relevant to some count outcomes; the primary endpoint is continuous and is described using a mean and standard deviation. The registry record does not report a model specification, diagnostics, or an assessment of over-dispersion, so no claim about those checks can be made.

More broadly, the analysis plan, handling of repeated observations, multiplicity procedures, and missing-data methods are not reported in the registry record. These details affect how an estimate should be interpreted and how well its uncertainty is represented. The outcome description and completers analysis identify some features of the approach, but they do not substitute for a full statistical analysis plan.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures, including the primary Five Times Sit-to-stand measure and secondary measures covering walking, function, cognition, pain, perceived effort, and physical health status. The primary endpoint is assessed at three and six months, while the outcome description says that the primary outcome has several categories or time points and is not reduced to one comparison. The registry also lists zero analyses in its analysis count.

When several outcomes or time points are examined, the chance of finding a statistically notable result by chance can increase if each is tested separately. General: multiplicity methods can control or otherwise address this issue, but the appropriate method depends on the prespecified questions and analysis plan. Whether the trial designated a hierarchy of outcomes, adjusted for multiple testing, or treated some comparisons as exploratory is not reported in the registry record. Numerical test results are not reported in the registry record, so the consequences of multiplicity cannot be evaluated.

The outcome analysis is described as unadjusted change among completers. The record gives the analysis counts for the community arm and the clinic arm at three and six months, but does not describe why participants lacked measurements, whether missingness differed by outcome, or how missing observations were handled beyond restricting the analysis to completers. It does not report imputation, weighting, or sensitivity analyses.

General: missing-data methods rely on assumptions about why measurements are unavailable. If those assumptions do not fit the data, an analysis can be biased even when its calculations are otherwise correct. A completers analysis can be straightforward to describe, but it may not preserve the balance created by randomization if inclusion in the analysis depends on post-randomization events. The registry record does not report enough information to assess the plausibility of those assumptions or the robustness of the findings to missing data.

The registry description does not report a full analysis population definition, protocol deviations, or an analysis plan specifying how repeated measures and multiple outcomes were to be handled. These omissions limit assessment of whether the reported analyses followed prespecified methods.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: fractured leg (1.7%), gout attack (1.7%), diabetic foot infection leading to leg amputation (1.7%).

The registry record reports serious adverse events in the community-based arm among 58 participants at risk, with 3 affected, and in the clinic-based arm among 53 participants at risk, with 0 affected. Other adverse events were reported among 58 participants at risk in the community arm, with 3 affected, and among 53 at risk in the clinic arm, with 2 affected. Deaths were reported as 0 in each arm. These are descriptive counts and should be read with their stated at-risk group sizes.

The record lists fractured leg, gout attack, and diabetic foot infection leading to leg amputation among the top serious-event terms, each with a listed frequency of 1.7%. The record does not establish in the information reported whether these events were caused by participation or by either program. The listed terms should not be treated as evidence of a program-related mechanism.

General: adverse-event counts can be compared descriptively, but small counts are imprecise and do not by themselves establish that one intervention is safer than another. A valid safety comparison would require attention to event definitions, follow-up duration, ascertainment, attribution, and the populations at risk. Those details are not reported in the registry record. The event counts also do not indicate the severity or duration of every non-serious event. They provide a record of reported events, not a complete causal assessment.

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

The trial asks a focused comparative question: whether a community-based or clinic-based chronic pain self-management program is associated with different changes in a timed sit-to-stand task. The registry record documents randomized assignment, parallel groups, behavioral programs, different meeting schedules, and outcome assessment at three and six months. It also describes a completers analysis of unadjusted change.

However, the numerical primary-outcome results are not reported in the registry record. There is no reported arm-specific mean change, arm contrast, confidence interval, or test result for the primary endpoint. Therefore, the record does not show whether the measured outcome changed differently between the groups, the direction or size of any difference, or how precisely an effect was estimated. The trial status is completed, but completion status is not itself an outcome finding.

Even if a numerical difference were available, it would describe the programs as delivered, not the effect of location alone. The community schedule involved nine meetings, while the clinic schedule involved six, and meeting length and format also differed. A between-arm contrast could therefore reflect multiple features of the program packages. The registry record does not report sufficient implementation or adherence detail to separate those influences.

General: statistical evidence and clinical importance are related but distinct. A small estimate may be precise yet not important to patients; a potentially important estimate may remain uncertain when data are limited or incomplete. Judging clinical importance would require a meaningful-change threshold or other clinical context, neither of which is reported in the registry record.

The findings, as recorded, do not justify claims that one program is superior, that either program is ineffective, or that the results apply to all people with chronic pain. The target population described is low-income Hispanic patients with chronic pain, and the official title and summary refer to opioid use. Eligibility details and information needed to judge broader generalizability are not reported in the registry record. The most defensible reading is that the registry supplies a description of the trial design and selected analysis details, but not enough primary-outcome data to determine the comparative result.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why design details and outcome reporting need to be read together. Randomized assignment establishes the intended basis for comparing the two program groups, while the parallel design indicates that participants were assigned to one program format rather than a sequence of both. But the programs differ not only in setting: meeting frequency, duration, and total number of meetings also vary. The statistical contrast therefore concerns two intervention packages.

The primary endpoint is a continuous functional measure, and the registry describes change from baseline at multiple follow-up times. Such outcomes invite questions about the scale of change, variability, baseline adjustment, and repeated measurement. The record reports an unadjusted completers approach, but not the numerical estimates or uncertainty needed to judge the contrast. This illustrates how a named endpoint and analysis description can clarify what was intended without communicating what the results were.

The record also makes the analysis population visible by reporting completer counts at relevant assessments. That is useful context because availability of follow-up measurements can affect precision and interpretation. Yet the absence of reported reasons for missing observations and sensitivity analyses leaves uncertainty about selection into the completers analysis.

Finally, multiple outcomes and time points create interpretive demands beyond any single comparison. Without a reported multiplicity strategy or full statistical plan, readers cannot determine how the analyses were prioritized or how uncertainty across outcomes was managed. These are not merely technical details: they affect how strongly an observed result, if reported, supports a focused conclusion. The registry record thus highlights the importance of complete outcome estimates, analysis methods, and missing-data reporting in clinical trials.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for statistical interpretation is that numerical results for the primary endpoint are not reported in the registry record. Without arm-specific changes, a between-arm estimate, or a measure of uncertainty, neither the direction nor precision of the primary comparison can be assessed. The record also identifies multiple categories or time points for the primary outcome without reducing them to one comparison.

The stated analysis is restricted to completers and uses unadjusted changes. Although the record gives assessment-specific analysis counts, it does not report reasons for missing measurements, baseline characteristics by analysis inclusion, or sensitivity analyses. As a result, the possibility that the completers differ systematically from those without follow-up cannot be evaluated. The record does not describe a baseline-adjusted analysis, a repeated-measures model, or an intention-to-treat analysis.

The intervention contrast combines several design features. Community and clinic programs differ in setting, meeting format, duration, frequency, and total number of meetings. The study therefore cannot, from the design description alone, isolate a setting effect from other program differences. Information on adherence, fidelity, and crossover is not reported in the registry record.

Other limitations include the absence of a reported statistical analysis plan, multiplicity approach, primary-outcome confidence interval, and numerical secondary-outcome results. The record lists the trial as completed but does not provide enough information to assess protocol adherence or the clinical importance of any change. Eligibility criteria and details of the population beyond the stated low-income Hispanic patients with chronic pain are also not reported. These gaps constrain conclusions about both internal validity and applicability to populations beyond those described.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Trial of Chronic Pain Self-Management in Clinic or Community for Low-Income Hispanics — NCT02906358.
• Registry record last updated 2018-11-05; status last verified 2017-01.
• Results first posted 2018-11-05.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed randomized, single-masked, parallel-group trial of community-based versus clinic-based chronic pain self-management for low-income Hispanic patients. Enrollment was 111. The primary endpoint was change from baseline in the Five Times Sit-to-stand measure at three and six months, recorded in seconds.

The community program involved nine meetings over six months; the clinic program involved six individualized meetings over six months. The analysis description specifies unadjusted change among completers and gives assessment-specific analysis counts. The record lists 12 outcome measures, but no analyses are counted and numerical primary-outcome results are not reported in the registry record. Serious adverse-event counts, other adverse-event counts, and zero deaths in both arms are listed. The absence of primary estimates and uncertainty measures prevents evaluation of the comparative functional outcome.