Comparative Effectiveness of a Peer-led O2 Infoline for Patients and Caregivers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparative Effectiveness of a Peer-led O2 Infoline for Patients and Caregivers (NCT02098369), a randomized phase 4 study. The primary outcome is Adherence to Supplemental O2 Prescription.

2. Clinical Question

3. Trial Design

The study, registered as NCT02098369, is titled Comparative Effectiveness of a Peer-led O2 Infoline for Patients and Caregivers. Its official title identifies it as PELICAN. The registry lists it as a phase 4, randomized, single-masked, parallel trial sponsored by the University of Illinois Chicago. Enrollment was 444. The study began in 2015-04, had primary completion in 2016-09, and is recorded as completed.

Participants were assigned to usual care, proactive coaching, or reactive coaching. Usual care consisted of basic written education material. Both coaching groups also received additional education material. Proactive participants received calls from peer coaches; reactive participants could call peer coaches. The record does not report who was masked or how masking was implemented. Details of sequence generation, allocation concealment, the exact randomization procedure, and any stratification are not reported in the registry record.

The primary outcome was assessed at 60 days and was defined as the number of participants using a stationary concentrator for a mean of at least 17.7 hours per day. The primary population was participants with evaluable oxygen-use data across all equipment. The registry also lists PROMIS physical function, fatigue, anxiety, sleep disturbance, depression, satisfaction with social roles and activities, and ability to participate in social roles and activities as secondary outcomes. Posted secondary results cover three of those measures; results for the other listed secondary outcomes are not reported in the registry record.

Beyond the listed endpoint populations and observed result counts, the registry does not report detailed recruitment, follow-up, protocol deviations, or analysis-population definitions. The reason for the enrollment target and the original sample-size assumptions 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: All participants with evaluable data for oxygen use across all equipment.

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 Supplemental O2 Prescription, measured over 60 days.

The primary endpoint counts participants who met a specific oxygen-use criterion: use of the stationary concentrator for a mean of at least 17.7 hours per day at the 60-day assessment. The registry labels this outcome adherence to the supplemental oxygen prescription. Its endpoint population is participants with evaluable oxygen-use data across all equipment.

A threshold outcome turns a continuous pattern of use into a count of participants meeting a prespecified criterion. It can be useful when the research question concerns whether participants reach a defined level of adherence. However, the count does not show how far below or above the threshold each person's use was, nor does it summarize use across participants who did not meet the criterion. The result therefore answers a particular adherence question rather than describing every aspect of oxygen use.

In the posted results, the registry reports 77 participants meeting the criterion in usual care, 73 in proactive coaching, and 97 in reactive coaching. The comparison groups' endpoint counts and evaluable denominators are used to describe the crude differences. The endpoint does not itself establish why participants met or did not meet the threshold. Additional details on how oxygen-use data were collected, how the mean was calculated, or how incomplete equipment data were handled are not reported in the registry record.

7. Results Posted in the Registry

• Proactive: 69.5% (73/105) versus 74.0% (77/104) on control; risk difference -4.5 percentage points (95% CI -16.7 to 7.7), risk ratio 0.94 (0.79–1.11); unadjusted two-proportion z-test p = 0.468.
• Reactive: 83.6% (97/116) versus 74.0% (77/104) on control; risk difference 9.6 percentage points (95% CI -1.2 to 20.4), risk ratio 1.13 (0.98–1.30); unadjusted two-proportion z-test p = 0.081.

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.

PROMIS - Physical Function

• 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 errors.
• Result:
  • Proactive: mean -0.10 versus -0.50 on control; difference 0.40 (95% CI -0.43 to 1.23), standardized effect d = 0.12; z-test p = 0.346.
  • Reactive: mean -0.20 versus -0.50 on control; difference 0.30 (95% CI -0.53 to 1.13), standardized effect d = 0.09; z-test p = 0.480.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Proactive and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Reactive and the control. The interval gives the range of effects that remain compatible with the data.

PROMIS - Fatigue

• 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 errors.
• Result:
  • Proactive: mean -1.00 versus 0.10 on control; difference -1.10 (95% CI -2.91 to 0.71), standardized effect d = -0.15; z-test p = 0.233.
  • Reactive: mean 0.30 versus 0.10 on control; difference 0.20 (95% CI -1.61 to 2.01), standardized effect d = 0.03; z-test p = 0.828.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Proactive and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Reactive and the control. The interval gives the range of effects that remain compatible with the data.

PROMIS - Emotional Distress - Anxiety

• 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 errors.
• Result:
  • Proactive: mean -1.20 versus 0.30 on control; difference -1.50 (95% CI -3.44 to 0.44), standardized effect d = -0.18; z-test p = 0.130.
  • Reactive: mean -0.10 versus 0.30 on control; difference -0.40 (95% CI -2.21 to 1.41), standardized effect d = -0.05; z-test p = 0.664.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Proactive and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Reactive and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary results cover PROMIS physical function, fatigue, and anxiety. Across these measures, the estimated mean differences are modest relative to their uncertainty, and each reported unadjusted confidence interval includes zero. The estimates do not show a consistent, clearly separated pattern across outcomes that independently resolves the uncertainty in the primary adherence comparison.

Secondary outcomes can provide useful context by describing other dimensions measured during the study. They address different constructs from the primary endpoint: the primary result concerns meeting an oxygen-use threshold, while the PROMIS measures concern reported functioning and symptoms. A pattern across secondary measures cannot be treated as a substitute for the primary comparison, nor does it directly establish how coaching affected oxygen adherence.

The record lists additional PROMIS outcomes for sleep disturbance, depression, satisfaction with social roles and activities, and ability to participate in social roles and activities, but their results are not reported in the registry record. The posted results therefore do not represent the full set of listed secondary measures.

Unadjusted secondary results carry less weight because multiple outcomes and group contrasts create opportunities for chance findings. The registry does not report whether secondary analyses were prespecified, whether a testing hierarchy was used, or whether p-values were adjusted for multiplicity. These results should be viewed as exploratory context rather than as a set of independent confirmations. They neither confirm nor negate the primary result; they show that the available secondary estimates also remain uncertain.

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

• PROMIS - Physical Function
• PROMIS - Fatigue
• PROMIS - Emotional Distress - Anxiety
• PROMIS - Sleep Disturbance
• PROMIS - Emotional Distress - Depression
• PROMIS - Satisfaction With Social Roles and Activities
• PROMIS - Ability to Participate in Social Roles and Activities

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is binary at the participant level: each evaluable participant either met the stated oxygen-use threshold or did not. The registry reports the numbers meeting the criterion and the denominators in each group. The comparison measure is a risk difference, which subtracts the control-group event probability from the intervention-group event probability. In general, a risk difference of zero corresponds to equal event probabilities; a positive value means the event probability is higher in the intervention group, and a negative value means it is lower. This is a general interpretation of the measure, not a claim about the trial's analysis plan.

What does a confidence interval describe?

A confidence interval expresses the statistical uncertainty around an estimated effect under the assumptions of the calculation. A wider interval indicates less precision than a narrower interval. If a risk-difference interval includes zero, the results are compatible with no difference as well as with effects in either direction within the interval. It is not a probability statement that the true effect lies in a particular interval, and it does not address bias, incomplete outcome data, or whether the endpoint is important to participants.

The displayed primary comparisons are simple unadjusted recalculations from the posted group summaries. They do not reproduce an unknown adjusted model. The registry record lists no reported analyses, so details such as covariate adjustment, model form, handling of repeated measures, or any planned hierarchy of tests are not reported in the registry record. The record also does not identify a primary statistical method or provide a sponsor-reported comparative estimate. The crude recalculations should therefore be read as descriptive estimates based on the recorded counts.

How should the PROMIS outcomes be read?

The posted PROMIS outcomes are continuous measures reported as group means with standard errors. The comparisons are mean differences between each coaching group and usual care. In general, a mean difference summarizes the separation between group averages on the measured scale, while its confidence interval conveys uncertainty around that estimate. A standard error describes uncertainty in an estimated mean; it is not the same as the spread of individual participant scores. The registry labels the reported dispersion as standard error.

For the secondary comparisons, the posted estimates are also unadjusted recalculations from summary statistics. They are not reported model estimates. No individual-level distributions, adjusted analyses, or additional analysis details are reported in the registry record. General caveats apply: group averages can conceal variation among participants, and a scale's numerical difference needs clinical and measurement context that is not established by the registry summaries alone.

Why do unadjusted tests need context?

An unadjusted p-value summarizes how incompatible the observed data are with a null hypothesis of no group difference under a specified statistical model. It does not give the probability that the null hypothesis is true, measure the size or importance of an effect, or show that a result will replicate. With several outcomes and contrasts, examining each p-value separately can make apparently unusual results more likely by chance. General statistical practice may address this through prespecified outcome hierarchies or multiplicity adjustments, but neither a planned method nor adjusted results are reported in the registry record.

Some statistical settings require methods that account for over-dispersion, meaning observed variability exceeds what a simpler model assumes. That issue is a general consideration for count data, but the primary endpoint is a participant count with a binary event definition, and the registry does not report a model or dispersion estimate. There is no basis in the record to assert that an over-dispersion correction was used or required.

The registry defines the primary population as participants with evaluable oxygen-use data across all equipment. This is important because the recorded result denominators are not identical across groups. The reasons for those denominators, the amount and pattern of missing data, and any imputation or sensitivity analyses are not reported in the registry record. The posted outcome counts therefore describe participants included in the stated evaluable population; they cannot alone show whether missingness affected the comparisons.

11. Confidence Intervals and Precision

Precision is best assessed from the confidence intervals around the group contrasts, rather than from the point estimates alone. For proactive coaching compared with usual care, the recalculated risk difference is -0.045 and its 95% confidence interval runs from -0.167 to 0.077. The interval extends to negative and positive values, so the observed data do not tightly distinguish the direction of the difference.

For reactive coaching compared with usual care, the risk difference is 0.096 and the 95% confidence interval runs from -0.012 to 0.204. The estimate is positive, but its interval crosses zero and includes a small negative difference as well as larger positive differences. This range reflects appreciable uncertainty about the size and direction of the contrast.

For both comparisons, the width of the interval is relevant to interpretation. A point estimate is one summary of the observed data, not a precise statement of the underlying effect. The intervals do not establish that groups are equivalent: such a conclusion would require a prespecified equivalence or noninferiority framework and suitable margins, which are not reported in the registry record.

The intervals are recalculations from posted summary statistics, not registry-reported adjusted intervals. They quantify sampling uncertainty under the simple calculation and do not account for possible bias, outcome missingness, deviations from the analysis assumptions, or multiple testing. The secondary mean-difference intervals likewise describe uncertainty in their unadjusted comparisons. Overall, the primary estimates are not precise enough to support a narrow conclusion about the size of either coaching contrast.

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 sample-size planning figures are illustrations based on the observed effect, not the trial's original design justification. The listed figures are participants per arm, not total participants and not total events. For the binary primary outcome, the values illustrate the approximate per-arm enrollment needed to detect the stated fraction of the observed effect under the listed assumptions.

The 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 the stated fraction of the observed effect. The 80% power column represents the per-arm planning size for a design with an 80% chance of detecting an effect of that size under those assumptions, if the effect and model assumptions hold. The 90% power column gives the corresponding planning size for a design with a 90% chance. These are prospective design calculations, not evidence about the probability that the completed study found a true effect.

For the primary outcome, separate planning illustrations are tied to the proactive-versus-usual-care and reactive-versus-usual-care observed effects. The effect fractions are 100%, 75%, and 50%. Smaller effects need more participants to detect under otherwise unchanged assumptions, which is why the planning figures rise as the target effect fraction decreases. The trial's own original sample-size assumptions and justification are not reported in the registry record.

This is not observed power. It does not describe the probability that the completed trial's result is correct, and it does not repair uncertainty in the estimated effects. The planning values depend on the observed effect used as their starting point; because observed effects themselves are uncertain, these figures are best read as planning illustrations rather than definitive enrollment recommendations.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.740; treatment proportion p₁ = 0.695; average p̄ = 0.718.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6365 = 1.2475.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6357 = 0.5350.
4. n = (1.2475 + 0.5350)² / (-0.0451)² = 1,558.9, rounded up to 1,559 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
p0 <- 0.740384615384615                          # control proportion
p1 <- 0.695238095238095                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2098369)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 1,559 (80% power), 2,087 (90% power)
 75% of observed effect: n per arm = 2,739 (80% power), 3,666 (90% power)
 50% of observed effect: n per arm = 6,084 (80% power), 8,144 (90% power)
power.prop.test: 1558.9 
Simulated power at n = 1,559 per arm: 0.800 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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. Multiplicity, Missing Data and Analysis Populations

The record lists one primary endpoint and several secondary outcomes, with comparisons of each coaching approach against usual care. When multiple endpoints or contrasts are examined, the chance of at least one apparently notable result can increase even when there is no underlying effect. This is the general multiplicity problem. Researchers may address it through prespecified priorities, adjusted significance thresholds, hierarchical testing, or by treating secondary analyses as exploratory.

The registry record does not report a multiplicity strategy, an outcome hierarchy, or adjusted p-values. It also does not provide reported analysis records. Consequently, the recalculated unadjusted p-values should not be interpreted as if they account for all comparisons. The registry does not report whether the primary comparison was the sole confirmatory test or how the secondary outcomes were intended to be interpreted.

Missing-data details are also limited. The primary endpoint population is described as all participants with evaluable oxygen-use data across all equipment. The posted group denominators differ, but the reasons for the evaluable counts, the number or pattern of missing observations, and the treatment of participants without evaluable data are not reported in the registry record. No imputation approach, missing-data sensitivity analysis, or comparison of included and excluded participants is reported.

The record does not report the original statistical analysis plan, details of the primary model, covariate adjustment, protocol deviations, or whether analyses followed assignment regardless of participation in coaching. The single-masked designation is recorded, but the masked parties and procedures are not reported. These omissions limit assessment of analysis choices and potential bias. They do not prove that such procedures were absent; they mean they are not documented in the registry record.

15. 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 serious adverse events and other adverse events by safety group. It records zero serious adverse events and zero other adverse events in each of the three groups. The reported numbers at risk for these safety summaries are 142 for usual care, 154 for proactive coaching, and 148 for reactive coaching. These safety denominators are not the same as the primary endpoint denominators and should be interpreted as the group sizes used for the adverse-event summaries.

No serious adverse event terms are listed. Death counts are not reported in the registry record. The zero recorded event counts mean that no events were entered in these categories for the reported groups; they do not establish that there was no risk, nor do they show whether all relevant events were captured. The registry record does not report event-collection procedures, severity grading details, follow-up duration for safety, or a statistical comparison of adverse-event rates. The figures are descriptive and do not support a comparative safety conclusion on their own.

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

The primary result describes whether participants with evaluable oxygen-use data met a specific threshold for stationary-concentrator use at 60 days. The observed counts are 77 in usual care, 73 in proactive coaching, and 97 in reactive coaching. Recalculated risk differences compare each coaching group with usual care; their confidence intervals include zero. The point estimates suggest different directions for the two comparisons, but the uncertainty means the posted summary data do not establish a clear difference in either direction.

This does not establish that the approaches are equivalent. No equivalence margin or noninferiority framework is reported. It also does not show that the approaches have no effect; an imprecise estimate can be compatible with a range of effects. Interpretation should focus on the estimated contrasts and their uncertainty rather than using a thresholded p-value as a verdict.

The outcome is limited to the endpoint's operational definition: reaching the stated mean-use threshold for a stationary concentrator. It does not describe the full distribution of oxygen use, adherence to every aspect of a prescription, or use beyond the 60-day assessment. The registry also lists health-related secondary measures, but posted results are available for only some of those measures. The results do not establish longer-term effects or outcomes for caregivers.

The trial was randomized, but the registry summary does not report enough detail to reconstruct its analysis plan or determine how missing observations and multiple outcomes were handled. The recalculated contrasts are unadjusted and based on posted summaries. They should not be confused with a sponsor-reported adjusted analysis. No medical advice or treatment recommendation follows from these registry statistics alone.

17. Why This Trial Matters Statistically

This trial is statistically informative because it compares two distinct ways of delivering peer-led telephone support against a written-education usual-care group. The proactive approach placed calls from coaches; the reactive approach depended on participants calling coaches. Keeping these approaches as separate randomized groups makes clear that they are distinct comparisons rather than interchangeable versions of a single intervention.

The primary endpoint also illustrates the importance of defining an outcome operationally. The registry's threshold-based count focuses on participants meeting a specified daily-use criterion, while leaving other aspects of oxygen use outside that summary. Understanding exactly what was counted helps prevent a group count from being mistaken for a complete description of adherence.

The confidence intervals emphasize why estimates and precision must be read together. The primary point estimates differ in direction, yet both intervals include zero and span a range of possible effects. The results therefore illustrate the distinction between observing a numerical difference and obtaining a precise estimate that narrows the plausible magnitude of that difference.

Finally, the registry record demonstrates the role of transparent analysis reporting. It records randomization, masking status, endpoint definitions, group counts, and selected secondary outcomes, but not the original analysis plan, missing-data methods, or multiplicity approach. Such omissions constrain what can be inferred from summary results. Planning illustrations based on observed effects can help frame future design questions, but they cannot replace a prospective design justification or turn the completed results into evidence of observed power.

18. 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.

Several limitations are specific to the available registry record. The primary outcome depends on evaluable oxygen-use data across equipment, but details of data capture, equipment coverage, and the handling of unavailable measurements are not reported. The endpoint is measured at 60 days, so it does not describe longer-term adherence in the posted record.

The record reports basic group counts but no sponsor-reported comparative analysis or statistical analysis plan. The displayed contrasts are unadjusted recalculations, and no information is available about covariate adjustment, outcome hierarchy, or multiplicity correction. As a result, the primary and secondary p-values cannot be interpreted as documented confirmatory analyses.

The record identifies the study as single-masked but does not say who was masked or how masking was maintained. It does not report allocation concealment, participant flow, reasons for non-evaluable data, protocol deviations, or adherence to the coaching approaches. Those details are relevant to assessing bias and implementation but cannot be inferred from the group summaries.

Secondary results are posted for only three of the listed PROMIS outcomes; the remaining listed secondary results are not reported in the registry record. Safety data are presented as event counts, without detail on collection procedures or comparative analysis. These limitations concern the information available in the record and should not be taken as proof that unreported procedures or analyses were not conducted.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Comparative Effectiveness of a Peer-led O2 Infoline for Patients and Caregivers — NCT02098369.
• Registry record last updated 2018-08-06; status last verified 2017-11.
• Results first posted 2018-08-06.
• 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.

22. Record Summary

NCT02098369 is a completed, phase 4, randomized, single-masked, parallel study sponsored by the University of Illinois Chicago. It enrolled 444 participants and compared usual care with proactive or reactive peer-led oxygen coaching for patients with COPD receiving supplemental oxygen.

The primary outcome counted participants meeting the stationary-concentrator use threshold at 60 days. The recalculated unadjusted risk-difference intervals for both coaching comparisons include zero. Posted secondary results cover physical function, fatigue, and anxiety; results for other listed secondary measures are not reported in the registry record. The registry records zero serious and zero other adverse events in each safety group, while deaths are not reported. Original design assumptions, a statistical analysis plan, and detailed missing-data and multiplicity methods are not reported in the registry record.