Peer Mentorship: An Intervention To Promote Effective Pain Self-Management In Adolescents: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Peer Mentorship: An Intervention To Promote Effective Pain Self-Management In Adolescents (NCT01118988), a randomized na study. The primary outcome is Adherence to Physician Recommended CAM Therapies.

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group study with no masking. Its listed enrollment is 27, and its status is completed. The record gives a start of 2009-12 and a primary completion of 2011-06. No phase designation beyond NA is listed.

The randomized arms were Mentorship and Control. The mentorship intervention involved supervised, monitored contact by telephone and computer for 2 months, with the aim of encouraging skill-building. The Control arm received treatment as usual. The record describes mentors separately: they were recruited from the UCLA Pediatric Pain Program and were patients aged 14 to 18 who had learned to cope with pain. This mentor role should not be confused with assignment to receive the intervention.

The trial description refers to children with chronic pain disorders and lists several conditions, including irritable bowel syndrome, functional abdominal pain, fibromyalgia, complex regional pain syndrome, myofacial pain, chronic daily headaches, and migraine headaches. The listed primary outcome is attendance at physician-recommended CAM therapies, measured as visits per week after the intervention, at week 8. The broader description says pain and functioning were to be assessed at 2 months and again at 4 months.

Further details of the randomization procedure, allocation ratio, masking procedures beyond the listed absence of masking, and protocol-specific statistical plan are not reported in the registry record. The record does not establish that every measure named in the study description was analyzed or posted as a result.

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: One participant in the Mentorship group did not do the weekly CAM therapy tracking and is thus not included in the results for this measure.

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 Adherence to Physician Recommended CAM Therapies, measured over post intervention (week 8).

The primary endpoint is adherence to physician-recommended CAM therapies, expressed as visits to CAM therapists per week. It records attendance rather than pain intensity, physical functioning, or whether a participant benefited from a therapy. The registry description says the measure tracks attendance at CAM therapies recommended by the participant’s pain specialist physician.

Attendance can be relevant to a behavioral intervention because the mentorship was intended to encourage participation in skill-building programs. In this study, however, the endpoint is specifically the number of visits, not a direct measure of that encouragement, the quality of the visits, or changes in pain and functioning. Interpretation should therefore stay close to what was recorded: reported weekly visits after the intervention.

The posted summaries are means with standard deviations. A mean describes the average visit frequency in an arm; a standard deviation describes how dispersed individual observations are around that mean. These summaries do not show individual participant values. One participant in the Mentorship group did not complete weekly CAM therapy tracking and was excluded from this measure’s results, according to the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is continuous: it is a count-like measure recorded as visits per week and summarized by a mean and standard deviation. For this kind of outcome, an arm mean communicates the average observed value, while the standard deviation describes variability across participants. Neither summary alone is a test of a treatment contrast. The registry reports the arm summaries, but does not report an inferential comparison for the primary endpoint.

What does a randomized comparison estimate?

In general, randomization is intended to make the groups comparable at the start of a study, on average, so that a comparison can estimate the effect of assignment to one study arm rather than another. That general rationale does not remove uncertainty, especially when the endpoint summaries include few observations. A useful comparative report would identify the contrast being estimated and describe its uncertainty, commonly with a confidence interval, alongside an inferential test when one is part of the analysis plan.

A confidence interval is a range generated by a statistical procedure to express uncertainty around an estimate. Its interpretation depends on the procedure and assumptions used. The registry record does not report a confidence interval for the primary comparison, so the precision of an arm contrast cannot be read from the posted means and standard deviations alone. A p-value is also not reported; without it, the record does not provide a test-based assessment of the comparison.

What do the standard deviations tell readers?

A standard deviation describes the spread of individual observations around an arm mean. It is different from the standard error, which describes uncertainty in an estimated mean, and it is different from a confidence interval for a treatment contrast. Standard deviations can help readers see whether values within an arm vary, but the summary statistics do not reveal the shape of the data, whether there are unusual observations, or how the results change when individual observations are removed.

General statistical methods for continuous outcomes can rely on assumptions about the distribution of observations or model errors. Those assumptions matter when the sample is small or when the outcome is skewed. The registry record does not state which model or distributional assumptions were used for an inferential analysis, and no such analysis is listed. It is therefore not appropriate to infer an analysis method from the mean and standard deviation summaries.

Why do outcome counts matter?

The number of participants represented in an endpoint summary affects how much information it contains. The primary outcome summaries report 10 participants in Mentorship and 3 in Control. With limited observations, estimates can be strongly influenced by individual values, and the uncertainty of a comparison may be substantial. The registry record notes that one participant in Mentorship did not complete the weekly tracking and was excluded from the measure. It does not give a fuller account of missing observations, reasons for missingness in the other arm, or methods used to address missing data.

In general, missingness can affect an estimate if the participants with observed outcomes differ systematically from those without them. Whether that occurred in this study cannot be determined from the record. A complete-case summary describes those with data; it does not by itself show how missing observations might have affected the result.

What can planning illustrations say?

Sample-size calculations are planning tools that relate a chosen effect, variability assumptions, significance level, and allocation plan to a required number of participants. An illustration based on an observed effect is not a retrospective measure of the probability that the trial detected a true effect. Such planning illustrations do not change the evidence in the observed outcome summaries, and they are not observed power. The registry record does not report the trial’s own sample-size justification or its planning assumptions.

General statistical interpretation also distinguishes an estimate from its practical meaning. A difference in visits per week, even if estimated precisely, would address attendance as defined for this endpoint. It would not alone answer whether pain, functioning, or other health outcomes changed. In this record, a comparative estimate and its uncertainty are not reported, so statistical conclusions about an arm difference should remain limited.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Mentorship", "Control")
n   <- c(10, 3)
m   <- c(1.34, 2.23)
sp  <- c(0.64, 1.19)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Mentorship  10  1.340  0.640  0.882  1.798
CARM  Control  3  2.230  1.190  -0.726  5.186

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a broad set of outcomes. In addition to the primary measure of CAM therapy attendance, it names outcomes covering pain assessment, sleep quality, symptoms, anxiety sensitivity, health beliefs, emotion regulation, emotion expression, and functional disability. The record lists 12 secondary outcomes as posted, but does not provide secondary analysis results in the information reported for this endpoint.

When a study evaluates multiple outcomes or multiple time points, general statistical practice considers multiplicity: the chance of obtaining an apparently notable result can increase as more comparisons are made. Methods may address this through prespecified outcome hierarchies or statistical adjustments, among other approaches. The registry record does not report whether such methods were planned or used. No adjustment should be assumed.

The study description mentions assessment at 2 months and again at 4 months, while the primary endpoint is specified at post intervention (week 8). The record does not report a complete analysis schedule or identify which results correspond to each planned time point beyond the primary endpoint description.

For the primary measure, the record states that one participant in Mentorship did not do weekly CAM therapy tracking and was not included in the measure’s results. It does not report a detailed missing-data plan, imputation method, sensitivity analysis, or analysis-population definition. The posted outcome counts are 10 for Mentorship and 3 for Control; the reason those counts differ from the overall enrollment is not fully explained in the endpoint record. These limits mean that the summaries describe observed endpoint data, not necessarily every randomized participant.

12. 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 reports serious adverse events and other adverse events separately for Mentorship, Control, and Mentors. The number at risk is 16 in Mentorship, 4 in Control, and 7 in Mentors. The record reports zero serious adverse events and zero other adverse events in each of those groups.

These figures describe events recorded in the registry for the listed groups. They do not establish that no symptoms or health events occurred outside the definitions or reporting process used for adverse events. The record does not provide event descriptions because no serious-event terms are listed, and it does not supply further detail about how events were collected or classified.

Deaths are not reported in the registry record. The adverse-event groups include Mentors as well as the two randomized arms, so the groups should not be interpreted as three equivalent randomized treatment comparisons. These safety counts are descriptive; they do not provide a comparative estimate of risk or establish the safety of an intervention.

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

The registry record describes a randomized comparison of peer mentorship with treatment as usual and posts arm-level summaries for weekly attendance at CAM therapists after the intervention. The observed mean is 1.34 visits per week in Mentorship and 2.23 in Control. Standard deviations and endpoint counts are also reported. These data describe attendance among the participants whose outcome values contributed to the summaries.

The result does not, on its own, establish a statistically reliable difference between the arms. The record does not report a confidence interval, p-value, or other inferential comparison for this endpoint. The posted means therefore cannot be used to judge the precision of an arm contrast. Limited endpoint counts, especially in Control, further constrain how much can be concluded from descriptive summaries.

The measure captures visits, not the clinical content of those visits or changes in pain. It does not directly measure functioning, and it cannot stand in for all the outcomes included in the study’s broader rationale. The registry description states a hypothesis about pain and functioning at 2 and 4 months; the primary result concerns CAM attendance at week 8. The primary result does not demonstrate whether pain or functioning improved or whether any change persisted.

The record also cannot establish why the arm summaries differ, whether missing data affected them, or whether the observed pattern would be similar in another group of participants. The randomized design is relevant to the study question, but a design label alone does not substitute for reported analysis results. A cautious reading separates what is directly reported—the arm means, spreads, and counts—from what remains unreported: the comparative uncertainty and the results for broader health outcomes.

14. Why This Trial Matters Statistically

This trial is statistically informative in part because it highlights the difference between having randomized groups and having a reported comparative analysis. The registry identifies a randomized, parallel design, but the primary result is presented as separate arm summaries without a reported inferential contrast. Readers therefore have descriptive information but not a quantified estimate of how uncertain the between-arm comparison is.

The endpoint also illustrates why outcome definition matters. Visits per week are a behavioral attendance measure. They may be relevant to a mentorship program designed to encourage participation, but they are not the same as pain severity or functioning. Keeping the outcome’s meaning distinct from the broader study hypothesis prevents a narrow measure from being interpreted as evidence about outcomes it does not record.

The counts included in the outcome summaries are important context. A small number of observations limits the information available and makes it difficult to assess precision from the reported summaries alone. The one noted tracking omission in Mentorship also draws attention to the need for clear reporting of missing outcomes and analysis populations.

Finally, the record lists multiple secondary outcomes and more than one assessment time in the study description. Without a reported statistical plan or outcome-by-outcome analysis, readers cannot determine how multiplicity was handled or how the primary result fits with the full set of intended assessments. These are general interpretive issues, not evidence that a particular analysis was or was not conducted outside what is recorded.

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.

The central limitation for interpreting the primary result is that the registry reports means and standard deviations but no inferential comparison. A confidence interval and p-value are not reported in the registry record, and no analysis is listed. Thus, the precision and statistical uncertainty of a contrast between Mentorship and Control cannot be assessed from the posted endpoint summaries.

The endpoint counts are limited: 10 for Mentorship and 3 for Control. One participant in Mentorship is specifically noted as not completing weekly CAM therapy tracking and as excluded from the measure. The registry record does not explain all differences between overall enrollment and endpoint counts, nor does it detail the handling of missing outcome data. The possibility that observed participants differ from participants without data cannot be evaluated.

The measure captures CAM visits per week, not pain, functioning, or the quality and content of care. Although pain and functioning are mentioned in the study hypothesis, the primary outcome result does not establish findings for those outcomes. The study description refers to multiple conditions, but the record does not provide condition-specific endpoint summaries that would show whether results varied across them.

Details needed to fully assess the analysis are not reported in the registry record, including the randomization procedure, the statistical model, assumptions, the trial’s sample-size justification, and whether multiplicity methods were used. The record also does not describe the complete analysis population or provide individual-level data. These omissions limit independent assessment of robustness, generalizability, and the relationship between the primary result and the broader study objectives.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Peer Mentorship: An Intervention To Promote Effective Pain Self-Management In Adolescents — NCT01118988.
• Registry record last updated 2016-09-30; status last verified 2016-08.
• Results first posted 2016-03-09.
• 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

NCT01118988 is a completed, randomized, unmasked, parallel-group study sponsored by the University of California, Los Angeles. It evaluated peer mentorship intended to support pain self-management in adolescents with chronic pain conditions. The Mentorship arm received the intervention, while the Control arm received treatment as usual. Mentors were recruited separately to provide peer support.

The primary outcome was adherence to physician-recommended CAM therapies, measured as visits per week at post intervention (week 8). The registry reports a mean and standard deviation for each randomized arm, with outcome counts of 10 in Mentorship and 3 in Control. It does not report an inferential comparison for this endpoint. The broader study description refers to pain and functioning assessments at 2 and 4 months, but results for those outcomes are not established by the primary attendance summaries.