Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease (COPD): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease (COPD) (NCT00677690), a randomized phase 3 study. The primary outcome is Exercise Capacity.

2. Clinical Question

The question concerns a short-term comparison between two rehabilitation approaches, with exercise capacity as the primary outcome. The registry summary frames the study as testing whether adding quadriceps NMES to usual pulmonary rehabilitation may improve exercise capacity in people with COPD. The primary measure is distance walked during the 6MWT, reported in meters.

The record also lists dyspnoea, quality of life, and respiratory function as secondary outcomes. These provide additional clinical measurements, but they are distinct from the primary exercise-capacity question. The registry record does not report a detailed population description beyond COPD, nor does it give further eligibility characteristics in the information available for the trial results.

3. Trial Design

The study is listed as a completed, randomized, parallel-group phase 3 trial with no masking. The registry records an enrollment of 83 participants. In the posted primary outcome, 42 participants are listed in the neuromuscular stimulation and pulmonary rehabilitation group and 41 in the pulmonary rehabilitation group.

The comparison is between a combined program of NMES and pulmonary rehabilitation and pulmonary rehabilitation alone. Although sham electrical stimulation appears in the interventions list, the arm descriptions identify the comparison group as having undergone pulmonary rehabilitation. The record does not make clear whether participants in that group received sham stimulation in addition to rehabilitation, so the comparator is best described as the pulmonary rehabilitation arm as posted rather than assuming an additional procedure.

The primary outcome was assessed at 5 weeks. The outcome is continuous: distance in meters on the 6MWT, summarized as a mean and standard deviation in each group. Three secondary outcomes are posted at the same timeframe: dyspnoea, quality of life, and respiratory function.

The record gives a study start of 2007-01 and primary completion of 2008-03, and lists the status as completed. It identifies Fondazione Salvatore Maugeri as sponsor. The registry record does not report the original sample-size justification, planned recruitment target separate from enrollment, allocation sequence procedures, concealment procedures, or further details about masking. The analysis plan beyond the reported one-sided t-tests is 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.

Before assignment: 167 COPD patients were admitted.52 out of 167 did not meet the inclusion criteria.19 out of the remaining 115 patients refused to participate.13 out of 96 subjects subsequently dropped out due to acute exacerbation.Our definitive sample was therefore of 83 subjects

Overall Study

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 Exercise Capacity, measured over 5 weeks.

The primary endpoint is exercise capacity assessed with the six-minute walk test (6MWT), measured in meters at 5 weeks. The test records the distance a participant walks during a defined assessment period. It is used as a measure of functional exercise capacity in this trial because the study question concerns whether adding quadriceps neuromuscular electrical stimulation to pulmonary rehabilitation is associated with a different exercise-capacity result than pulmonary rehabilitation alone.

The registry summarizes this continuous outcome using a mean and standard deviation for each group. The posted mean was 465.5 meters for neuromuscular stimulation and pulmonary rehabilitation and 462.7 meters for pulmonary rehabilitation. The standard deviations were 101.7 and 96.9 meters, respectively. These summaries describe the observed group distributions; they do not by themselves establish whether a between-group difference is statistically distinguishable from zero or whether it is important to participants.

For interpretation, a comparison should be read alongside its uncertainty, the analysis method, and the registry’s own reported result. The reported outcome is at a single stated timeframe. Change from baseline, repeated assessments, and the handling of missing outcome measurements are not reported in the registry record.

7. Results Posted in the Registry

• Pulmonary Rehabilitation: mean 462.70 versus 465.50 on control; difference -2.80 (95% CI -45.53 to 39.93), standardized effect d = -0.03; z-test p = 0.898.

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.

Dyspnoea

• 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:
  • Pulmonary Rehabilitation: mean 2.60 versus 2.40 on control; difference 0.20 (95% CI 0.06 to 0.34), standardized effect d = 0.63; z-test p = 0.004.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Pulmonary Rehabilitation than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Quality of Life

• 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:
  • Pulmonary Rehabilitation: mean 42.05 versus 41.70 on control; difference 0.35 (95% CI -6.22 to 6.92), standardized effect d = 0.02; z-test p = 0.917.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Pulmonary Rehabilitation and the control. The interval gives the range of effects that remain compatible with the data.

Respiratory 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 deviations.
• Result:
  • Pulmonary Rehabilitation: mean 49.60 versus 50.10 on control; difference -0.50 (95% CI -3.67 to 2.67), standardized effect d = -0.07; z-test p = 0.757.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Pulmonary Rehabilitation and the control. The interval gives the range of effects that remain compatible with the data.

The registry posts three secondary outcomes at 5 weeks: dyspnoea, quality of life, and respiratory function. Across them, the recalculated comparisons do not all follow the same statistical pattern. The dyspnoea comparison has an unadjusted p-value of 0.004 and a confidence interval that does not include zero; the quality-of-life and respiratory-function intervals include zero, and their unadjusted p-values are 0.917 and 0.757. These are recalculations from posted summaries, not substitutes for the registry’s own reported tests.

The registry lists one-sided t-tests with p <0.05 for these outcomes as well, creating a mismatch with the recalculated entries for quality of life and respiratory function. The discrepancy flagged for the trial also cautions against treating the recalculated secondary comparisons as definitive sponsor results. The registry does not provide estimates or confidence intervals for the sponsor-reported tests, so the sponsor analyses cannot be evaluated for magnitude and precision from those entries.

The secondary outcomes add context to the primary exercise-capacity result, but they do not answer the primary question directly. An outcome pattern across several measures should not be taken as confirmation or refutation of the primary finding without considering the trial’s prespecified analysis plan and the relationship among the outcomes. The registry record does not report a multiplicity adjustment or a hierarchy for secondary testing.

Unadjusted secondary results generally carry less weight because multiple outcomes create more opportunities for apparently notable findings, particularly when no adjustment or prespecified testing strategy is documented. This is a general statistical concern, not evidence that any particular result is spurious. The secondary results are best treated as supportive or exploratory observations, with attention to the conflict between the reported tests and recalculations and the limited analysis details in the registry.

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

• Dyspnoea
• Quality of Life
• Respiratory Function

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous and is reported as a mean with a standard deviation in each randomized group. A mean describes the group’s average observed distance, while a standard deviation describes how spread out individual distances are around that average. These summaries are useful for understanding the observations, but an inferential comparison also needs to account for the uncertainty in the estimated difference between groups.

What does a mean difference represent?

The unadjusted recalculation compares the posted mean for the pulmonary rehabilitation group with the posted mean for the combination group, using the orientation stated in the comparison. The resulting estimate is -2.8 meters. A mean difference of zero would correspond to equal group means in the population under the comparison model. A positive or negative estimate describes direction according to the selected group ordering; it should not be interpreted without checking which group is subtracted from which. The sign alone is not a clinical judgment.

The recalculation is unadjusted: it uses the posted group-level summaries rather than adjusting for baseline measurements or other participant characteristics. It is not necessarily the same analysis as the sponsor’s original model. The registry’s reported primary method is a one-sided t-test, but the details needed to reproduce that analysis are not posted. The recalculated p-value of 0.898 is an unadjusted result, and it should be kept distinct from the sponsor-reported p <0.05.

How should a p-value be read?

A p-value describes how compatible the observed data are with a specified null model, given the assumptions of the test. It is not the probability that the null hypothesis is true, and it does not measure the probability that a result occurred by chance in an everyday sense. A small p-value can be evidence against the null model under the analysis assumptions, but it does not describe the size, precision, or clinical relevance of a difference. The registry reports a one-sided test; a one-sided test evaluates evidence in a specified direction, so its interpretation depends on the direction and hypotheses set out in the analysis plan. That plan is not reported in the registry record.

The sponsor-reported p-value and the recalculated p-value cannot be treated as interchangeable. The reported entry gives p <0.05 without a test statistic or estimate. The recalculation uses the posted means, standard deviations, and group sizes and gives p = 0.898. The registry record does not state whether the reported test used other data, adjustments, or analysis choices that could account for the discrepancy. None should be assumed.

What does the confidence interval add?

A confidence interval gives a range of effect estimates compatible with the data and the interval method, under its assumptions. The recalculated 95% interval for the primary mean difference runs from -45.53 to 39.93 meters. Because it crosses zero, it includes no difference as well as estimates in either direction. It is also broad enough to include differences that may matter, although no clinical-importance threshold is reported. A confidence interval is not a guarantee that the true value lies within the displayed range, nor does it resolve the conflict with the sponsor’s test.

Standard errors describe sampling uncertainty in an estimate. The posted recalculation gives standard errors for the group means of 15.69 and 15.13 meters. These are distinct from the standard deviations, which describe participant-to-participant spread. Uncertainty in a between-group contrast depends on the variability and size of both groups, as well as on the analysis assumptions.

Why can analyses differ?

Different statistical methods can produce different estimates or p-values when they use different analysis populations, covariate adjustments, assumptions, or handling of missing observations. These are general possibilities, not explanations established for this trial. The registry record does not report enough information to identify the reason for the discrepancy. The sponsor’s own analysis takes precedence where the discrepancy is flagged, while the recalculation remains informative as a transparent check of the posted summaries.

The posted outcomes are analyzed at a single stated timeframe and the record does not describe baseline adjustment, repeated-measures modeling, missing-data methods, or analysis populations. The reported one-sided t-tests are listed for the primary and secondary outcomes, but their detailed specification is not reported in the registry record. Thus, the posted summaries support a straightforward descriptive comparison, while important aspects of the planned and performed inferential analyses remain unclear.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate a group difference. For the primary outcome, the unadjusted recalculated mean difference is -2.8 meters, and the 95% confidence interval extends from -45.53 to 39.93 meters. The interval includes zero, so the recalculation is compatible with no mean difference as well as with differences in either direction. Its breadth means that the posted summaries do not pin down the size of the difference closely.

The confidence interval is derived from the posted group summaries and is not the interval reported by the sponsor. The registry lists a sponsor-reported one-sided t-test with p <0.05 but provides no accompanying estimate or confidence limits. Consequently, the precision of the sponsor’s result cannot be assessed from that reported analysis entry. The disagreement between the reported test and the recalculation also makes it especially important not to present the recalculated interval as if it were the sponsor’s result.

A confidence interval should not be read as a range of values that are equally likely, nor as proof that values outside it are impossible. It summarizes uncertainty under the method used. The registry record does not report a threshold for a clinically meaningful change, so the interval cannot be classified against a trial-specific importance threshold. It also does not report a noninferiority or equivalence margin; therefore, an interval that includes zero cannot establish equivalence.

The available interval pertains to the 5-week primary endpoint only. It does not describe longer-term precision or the precision of individual participant outcomes. The sponsor analysis, missing-data handling, and any analysis population definitions are not described in enough detail to determine whether they would yield a different interval.

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 illustrations use the recalculated observed effect as a starting point and show hypothetical participant requirements for detecting fractions of that effect. The displayed figures are participants per arm, not total participants, for this continuous-outcome comparison. They are not the original trial’s design calculations. The trial’s own sample-size justification and original design assumptions are not reported in the registry record.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set to the stated fraction of the observed effect. Under each effect scenario, the 80% power column gives the number of participants per arm that the illustration estimates would be needed for an 80% chance of detecting that target effect, if the assumptions hold. The 90% power column gives the corresponding per-arm planning number for a 90% chance. These are planning probabilities under the assumed model, not guarantees for a future study.

The rows vary the target from 100% of the observed effect to 75% and 50% of that effect. Smaller target effects require more participants because they are harder to distinguish from the background variability. For the primary endpoint, the observed difference is very small relative to its uncertainty, so the illustrated requirements are very large. The figures should not be interpreted as a recommended design without a justified target effect and appropriate design assumptions.

These calculations are planning illustrations, not observed power. They do not describe the trial’s probability of success after completion, and they do not resolve the disagreement between the sponsor-reported test and the unadjusted recalculation. A plotted curve, if read alongside the figures, represents the same planning relationship between target effect size and the number of participants required under the stated assumptions.

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 = -2.800; pooled standard deviation σ = 99.359.
2. n = 2 × (1.96 + 0.842)² × 99.359² / -2.800² = 19,766.6, rounded up to 19,767 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 <- -2.80000000000001                      # observed difference in means
sigma <- 99.3586153508816                     # 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(677690)
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 = 19,767 (80% power), 26,462 (90% power)
 75% of observed effect: n per arm = 35,141 (80% power), 47,044 (90% power)
 50% of observed effect: n per arm = 79,067 (80% power), 105,848 (90% power)
power.t.test: 19767.6 
Simulated power at n = 19,767 per arm: 0.799 (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 one-sided t-test for the primary comparison and gives p <0.05. It does not provide the sponsor’s estimated mean difference, test statistic, or confidence interval. The unadjusted recalculation from the posted group means, standard deviations, and sample sizes gives a mean difference of -2.8 meters, a 95% confidence interval from -45.53 to 39.93 meters, and p = 0.898. These analyses do not agree on statistical significance.

The discrepancy flag is true, so the sponsor’s own analysis takes precedence over the recalculated analysis when describing the registry’s reported finding. The recalculation should be presented as a separate, unadjusted check of the posted summary statistics. It cannot replace the sponsor’s result, and the sponsor’s reported p-value cannot be used to infer an effect estimate or precision that the registry does not provide.

The registry record does not explain why the analyses differ. It does not give enough detail to determine whether the reported test used another analysis population, adjustment, data handling approach, or other method. Those are possible general sources of differences, not established features of this trial. The appropriate reading is therefore to report both results clearly, acknowledge that they conflict, and avoid choosing an explanation not documented in the record.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several hypotheses are tested. With multiple outcomes, timepoints, subgroups, or analysis choices, the chance of at least one apparently notable result can increase unless the testing strategy accounts for the number and order of comparisons. This is a general statistical principle. The registry posts one primary outcome and three secondary outcomes, but the registry record does not report a multiplicity adjustment, a testing hierarchy, or a detailed plan for interpreting the secondary analyses.

The registry lists a one-sided t-test for the primary and secondary outcomes. It does not report the directional hypotheses, the planned handling of multiple tests, or whether the listed tests were the only analyses conducted. Those details are not reported in the registry record. Consequently, the secondary p-values should not be interpreted as if they had necessarily been adjusted for the number of outcomes.

Missing data can affect group comparisons if outcome observations are unavailable and the pattern of missingness relates to participants’ outcomes or group assignment. The registry record does not report the number of missing 5-week measurements, the reasons for missingness, any imputation method, or a sensitivity analysis. The posted outcome sample sizes do not establish how missing measurements, if any, were handled in the reported analysis.

The analysis population is also not described in detail. The record does not state whether the reported tests used all randomized participants, participants with available outcome data, or another defined population. No conclusion about intention-to-treat analysis, per-protocol analysis, or exclusions can therefore be drawn from the available entry.

These gaps matter because the sponsor-reported primary result differs from an unadjusted recalculation, and the record does not give enough methodological detail to reconcile the difference. They also limit assessment of whether the secondary testing and missing-data handling could influence the results. The uncertainty is about what the registry reports, not proof that any particular method was or was not used.

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

The record describes a randomized comparison of neuromuscular electrical stimulation combined with pulmonary rehabilitation against pulmonary rehabilitation, with exercise capacity measured by the 6MWT at 5 weeks. The posted means are similar in size, and the recalculated primary comparison is imprecise. However, the registry’s own reported one-sided test gives p <0.05, while the unadjusted recalculation gives p = 0.898. The record does not explain this disagreement, so neither result should be presented without qualification.

The reported sponsor analysis is the registry’s stated analysis and takes precedence when a discrepancy is flagged. At the same time, the missing effect estimate and confidence interval for that analysis mean that its magnitude and precision are not available in the registry entry. The recalculated result makes transparent what follows from the posted summary statistics, but it is not a replacement analysis and does not settle the sponsor result.

These data do not establish that the groups are equivalent. A nonsignificant recalculated comparison would not, by itself, show that any important difference has been excluded; its confidence interval includes a range of possible differences, and no clinical-importance threshold is given. Conversely, the sponsor-reported p-value alone does not establish how large or meaningful the difference is.

The findings are limited to the posted 5-week outcomes. The record does not provide longer-term results, change-from-baseline details, or enough information about missing data and analysis populations to extend the interpretation beyond the reported comparisons. The secondary outcomes offer additional measures but are subject to the same reporting limitations and the general concern about multiple testing.

Statistical evidence describes uncertainty in group comparisons under particular methods. It does not by itself establish a clinical benefit, harm, or treatment recommendation. This interpretation is about the posted trial data and the limits of the registry record, not advice for individual care.

17. Why This Trial Matters Statistically

This trial illustrates why a result should not be reduced to a single p-value. The registry reports a one-sided test with p <0.05 for the primary outcome, while an unadjusted recalculation from the posted means and standard deviations gives p = 0.898 and a 95% confidence interval spanning -45.53 to 39.93 meters. The difference between these records is statistically important: it changes the apparent conclusion, and the registry does not explain why.

It also shows the value of reporting effect estimates and confidence intervals alongside tests. A p-value alone cannot show the magnitude or precision of an effect. The sponsor-reported entry lacks an estimated difference and interval, while the recalculation can estimate these from posted summaries but may not reflect the sponsor’s analysis choices. Neither item alone provides a complete account.

The trial is a useful example of distinguishing observed results from planning illustrations. Sample-size figures derived from an observed effect are not observed power and do not reveal the original design rationale. In this case, the very small recalculated primary difference relative to its uncertainty leads to large illustrative participant requirements, but those figures depend on assumptions and a chosen target effect.

Finally, the three secondary outcomes raise familiar interpretive issues: multiple comparisons, differing results across measures, and incomplete reporting of analysis plans. Together, these features emphasize transparent reporting of methods, analysis populations, missing data, and prespecified hypotheses. Without those details, readers can describe what is posted but cannot fully reconstruct or reconcile the statistical analysis.

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.

The registry record leaves several trial-specific questions unresolved. It lists sham electrical stimulation among the interventions, but describes the comparator arm as pulmonary rehabilitation. The record does not clearly state whether the comparator participants received sham stimulation, so the precise contrast in treatment procedures cannot be fully reconstructed from these entries.

The primary outcome is reported at 5 weeks, without posted baseline values or a change-from-baseline analysis. The registry record does not report whether the displayed means represent all randomized participants or a subset with available measurements. It also does not report missing-outcome counts, reasons for missingness, exclusions, or missing-data methods. These omissions limit assessment of the analysis population and potential effects of incomplete observations.

The reported analysis is listed as a one-sided t-test, but the detailed statistical plan is not reported in the registry record. The reason for using a one-sided test, the directional hypothesis, and any adjustment or covariate strategy are not stated. Most importantly, the reported p-value conflicts with the unadjusted recalculation, and the registry does not provide the information needed to determine why.

The outcome record does not provide a clinical-importance threshold for the 6MWT, nor does it report an equivalence or noninferiority margin. Thus, the recalculated interval cannot be evaluated against a trial-specific meaningful-difference benchmark. Follow-up beyond the stated timeframe and longer-term outcome results are not reported in the information available.

For adverse events, the registry lists zero participants at risk and zero affected for both serious and other events in each group, while death counts are null. These entries do not provide detail about event definitions, collection, or completeness, and should not be interpreted as a detailed safety assessment. The record also does not provide further population characteristics beyond COPD.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease (COPD) — NCT00677690.
• Registry record last updated 2011-11-16; status last verified 2011-11.
• Results first posted 2009-04-20.
• 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

NCT00677690 is listed as a completed, randomized, parallel-group phase 3 trial with no masking and enrollment of 83 participants. The study compared neuromuscular electrical stimulation combined with pulmonary rehabilitation with pulmonary rehabilitation. The primary outcome was 6MWT exercise capacity in meters at 5 weeks.

The posted primary group means were 465.5 and 462.7 meters. The registry reports a one-sided t-test with p <0.05, while an unadjusted recalculation gives a mean difference of -2.8 meters, a 95% confidence interval from -45.53 to 39.93 meters, and p = 0.898. The discrepancy is flagged, and the record does not explain it; the sponsor’s own analysis takes precedence.

Three secondary outcomes are posted: dyspnoea, quality of life, and respiratory function. The record does not report the original sample-size justification, a detailed statistical analysis plan, missing-data methods, or analysis populations.