Effectiveness of Respiratory Physiotherapy in Children With Neuromuscular Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of Respiratory Physiotherapy in Children With Neuromuscular Disease (NCT02743702), a randomized na study. The primary outcome is Change From Baseline Vital Capacity at One Year..

2. Clinical Question

The comparison was randomized, parallel, and described as having a blinded evaluator. The principal posted result is a median percentage change in vital capacity for each group and a reported Wilcoxon (Mann-Whitney) comparison. The result describes the participants with posted outcome data; the record does not give enough information to establish how missing measurements, if any, were handled or which analysis population was used.

3. Trial Design

The registry describes a randomized clinical trial with two parallel groups and a single masking designation. Its official title describes a blinded evaluator; the identity of the person or people masked, and whether participants or treating staff were masked, are not reported in the registry record. The study is marked completed, with a recorded enrollment of 21. The record lists University of Seville as sponsor and records a start in 2012-06 and primary completion in 2014-06.

One group received respiratory physiotherapy and the other continued usual therapies without a physiotherapy approach to respiratory difficulties. The intervention description specifies physiotherapist sessions once a week and family practice at home four times more, for one year. Sessions lasted between 30 and 45 minutes, with duration varying by patient cooperation. The description of the exercise program is cut off in the registry record, so its full content and implementation cannot be characterized from this information. The usual-therapy group’s other care is not described in detail.

The primary outcome was change from baseline vital capacity at one year, evaluated by spirometer and expressed as percentage change. The posted group summaries are for 11 participants receiving respiratory physiotherapy and 10 receiving usual therapies. These outcome counts are consistent with the recorded enrollment, but the registry does not state whether all randomized participants contributed to the primary analysis or whether any measurements were missing.

The registry lists one outcome measure and one reported analysis. It does not report the randomization procedure, allocation concealment, trial protocol, sample-size justification, recruitment details, participant flow, or analysis population. The registry also does not report whether any interim analyses were planned or conducted. These omissions limit how fully the conduct and prespecification of the trial can be assessed.

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

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 Change From Baseline Vital Capacity at One Year., measured over At baseline and at 1 year.

The primary endpoint is the change from baseline in vital capacity at one year. Vital capacity is a measure of the volume of air a person can exhale after taking a full breath; in this study it was evaluated by spirometer. Expressing change as a percentage allows the outcome to describe relative change from each participant’s baseline rather than only an absolute volume. The registry does not give the underlying spirometry units or further measurement details.

The registry reports the endpoint as a median with an inter-quartile range for each group. The median is the middle value when measurements are ordered, while the inter-quartile range describes the middle half of the observed values. These summaries are useful when outcome values are skewed or when a small number of observations may be far from the rest. They do not show the full distribution, and the reported group summaries do not, by themselves, describe each participant’s change.

Vital capacity was selected as the primary measure because the stated study objective concerned improvement or maintenance of respiratory function. The endpoint provides a spirometric measure relevant to that objective. The registry’s broader description also mentions respiratory infections and related care, but no results for those secondary questions are posted. The record does not explain the clinical threshold for a meaningful change in vital capacity, so the size of a change cannot be classified as clinically important from the posted information alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The posted primary outcome is a percentage change from baseline in vital capacity at one year. The analysis reports a median and inter-quartile range for each group, followed by a Wilcoxon (Mann-Whitney) test. These choices describe the location and spread of the observed measurements and compare the groups without relying on the same distributional assumptions as a conventional comparison of means. The registry does not report a fuller statistical analysis plan, so the reasons for selecting these methods are not stated.

What do the medians and inter-quartile ranges describe?

A median is the central observation after measurements have been ordered. It is less influenced by very high or very low observations than an arithmetic mean. The inter-quartile range gives the interval between the lower and upper quartiles, enclosing the middle half of the values. Together, these summaries indicate both a typical position and variation among the observed participants. They do not reveal the shape of the distribution, the presence of clusters, or the measurements of individual participants.

The registry reports 33.33 as the median percentage change for the respiratory physiotherapy group, with an inter-quartile range of 11.11 to 89.74. For usual therapies, it reports -7.41, with an inter-quartile range of -15.6 to -3.82. These are within-group summaries. A comparison of the medians themselves would require an estimated contrast and its uncertainty; neither is reported as a numerical effect estimate in the registry record.

What does the Wilcoxon (Mann-Whitney) test assess?

The Wilcoxon rank-sum test, also called the Mann-Whitney test, orders the combined outcome observations and compares how the ranks are distributed between independent groups. In broad terms, it assesses whether values from one group tend to rank differently from values in the other group. It is often useful when measurements are skewed or when a mean-based model is not considered suitable. As a general statistical point, the test is not automatically a test of a difference between medians: that interpretation requires additional assumptions about the shapes of the two distributions.

The registry reports p < 0.001 for this comparison. The p-value indicates how incompatible the observed test result is with the null hypothesis used by the test, assuming the test’s framework applies. It does not report an effect size or a confidence interval, and it does not tell the reader whether the magnitude of change is clinically meaningful. The registry does not include a test statistic or a more detailed description of the test implementation.

How should statistical significance and precision be distinguished?

A small p-value and a precise estimate are related but different ideas. The p-value summarizes evidence against a null hypothesis under the chosen test. A confidence interval for an effect estimate would show a range of values compatible with the data and model, conveying uncertainty in the estimated contrast. No confidence interval for the between-group effect is reported. The inter-quartile ranges are descriptive intervals for the observed participants, not confidence intervals for the group medians or for the treatment contrast.

Because the trial’s enrollment was 21, the estimated distributions and rank comparison are based on a small participant set. In general, small studies can yield unstable estimates, and the result may be sensitive to individual observations. That concern does not negate the reported test result, but it makes the absence of an effect estimate and uncertainty interval especially relevant when judging the scale and precision of the contrast. No alternative analyses or sensitivity analyses are reported in the registry record.

What can randomization contribute?

Random allocation is intended to make group assignment independent of participants’ characteristics, on average, reducing systematic selection differences. In a small trial, randomization does not guarantee that every baseline characteristic is balanced. The registry does not report baseline characteristics, how the random sequence was generated, or how assignment was concealed. The designation of a blinded evaluator may reduce the risk that outcome assessment is influenced by knowledge of group assignment, but the details of masking are not reported.

The parallel design means that the groups were followed as separate treatment groups rather than participants crossing between treatments. The registry reports the group outcomes at one year. It does not report whether the analysis followed an intention-to-treat principle, how adherence was handled, or whether participants were analyzed according to assigned group. These choices can affect the interpretation of randomized comparisons, particularly if follow-up or treatment receipt differs between groups.

Why does over-dispersion matter in general?

As a general statistical concept, over-dispersion occurs when observed variability is greater than a model assumes. A model that understates variability can produce uncertainty estimates that are too narrow and tests that are too optimistic. Over-dispersion is particularly relevant in count outcomes, but the registry’s primary endpoint is a continuous spirometric change summarized by medians and inter-quartile ranges, and no count model is reported. The registry does not report a dispersion assessment or a model-based analysis for this endpoint.

In general, the chosen analysis should match the endpoint’s scale, distribution, design, and missing-data structure. The registry names a nonparametric two-group test, but does not document diagnostic checks or further assumptions. That lack of detail does not justify replacing the reported analysis with a different one; it limits how fully an independent reader can evaluate whether the method was appropriate.

What information is missing for a fuller analysis?

The registry does not report a protocol, a prespecified statistical analysis plan, a sample-size justification, the analysis population, participant flow, missing-data procedures, baseline outcome values, or individual observations. It also does not provide a confidence interval or an explicit between-group effect estimate. These details would help assess prespecification, completeness, precision, and robustness. Their absence means the reported result can be described, but the statistical analysis cannot be reconstructed in full from the registry record.

10. Analyses Reported by the Sponsor

The registry’s reported analysis is the Wilcoxon (Mann-Whitney) comparison of the respiratory physiotherapy and usual-therapies groups, with p < 0.001. The posted summaries give the group medians and inter-quartile ranges, but no numerical estimate or confidence interval for the between-group contrast. No independent recalculated contrast or interval is reported in the registry record, so there is no recalculation to compare numerically with the sponsor’s test result.

The registry does not flag a discrepancy between the sponsor’s reported result and a recalculation. In general, a recalculation from summary statistics is unadjusted and may not reproduce a sponsor’s analysis if the latter uses participant-level data, a different analysis population, or adjustments not reflected in the summaries. If a discrepancy were identified, the sponsor’s own analysis would take precedence for describing the trial’s reported analysis. No such discrepancy is indicated.

The reported p-value should therefore be read as the result of the named sponsor analysis, rather than as a substitute for an effect estimate or precision interval. The registry does not report enough analysis detail to independently verify the test implementation or determine whether the analysis followed a prespecified plan.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure and one reported analysis. It does not report results for secondary outcomes, although the study description discusses respiratory infections, antibiotic need, emergency-room visits, and hospital admissions. No secondary outcome results are posted. The registry does not state whether these outcomes were prespecified as formal secondary endpoints, whether they were collected, or whether analyses were conducted.

Multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. Repeated testing can increase the chance of at least one apparently notable result under a collection of null hypotheses. Statistical plans can address this through prespecified outcome hierarchies or adjustments, among other approaches. The registry record does not report whether a multiplicity strategy was planned or applied. Because only one analysis is posted, the record alone does not establish how many analyses were considered during the study or whether the reported analysis was the sole planned analysis.

The registry does not report an analysis population, participant flow, missing-data procedures, or the number of participants with unavailable primary measurements. The group summaries list 11 participants in the physiotherapy group and 10 in the usual-therapies group, but these figures do not establish whether all randomized participants were analyzed under an intention-to-treat approach. The record does not say whether missing outcomes were excluded, imputed, or handled by another method.

These omissions matter because missingness can affect a comparison if the probability of an unavailable measurement is related to group assignment or outcome. As a general statistical principle, complete-case analysis can be biased when the participants with observed outcomes differ systematically from those without them. The registry does not permit assessment of that possibility. It also does not report sensitivity analyses to examine how conclusions might change under different assumptions about missing data.

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 zero serious adverse events among 11 participants at risk in the respiratory physiotherapy group and zero among 10 participants at risk in the usual-therapies group. It also reports zero other adverse events among the respective groups of 11 and 10 participants at risk. These entries describe the safety figures recorded in the registry; they do not establish that no adverse experiences occurred outside the categories or reporting period captured by the record.

The registry does not list serious adverse event terms and does not provide death counts. A null entry for deaths is not a reported count of zero, so mortality cannot be characterized from the posted information. The record also does not specify the adverse-event collection methods, event definitions, severity criteria, follow-up duration for safety, or whether events were assessed as related to treatment.

Zero recorded events in a small group do not establish that an intervention has no safety risks. Such figures can only describe what was recorded among the participants at risk in this trial. They should not be treated as a precise estimate of how often events would occur in a broader population, particularly without information about surveillance and reporting procedures.

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

The registry’s primary result shows that the reported vital-capacity change distributions differed between the randomized groups under the Wilcoxon (Mann-Whitney) analysis, with p < 0.001. The group medians were 33.33 for respiratory physiotherapy and -7.41 for usual therapies. The associated inter-quartile ranges show that participant outcomes varied within each group. This is a description of the posted result, not a statement that every participant experienced the group median or moved in the same direction.

The result does not, on its own, establish the size or precision of the between-group effect. No contrast estimate or confidence interval is reported. The p-value does not indicate the probability that the null hypothesis is true, and it does not measure the clinical importance of the observed changes. The registry does not state a threshold for a clinically meaningful change, so statistical evidence and clinical importance cannot be equated from this record.

The trial’s randomization supports a comparison between assigned groups in principle, but important design and analysis details are unavailable. The registry does not report baseline characteristics, the allocation procedure, the analysis population, missing-data handling, or whether the outcome analysis was prespecified. These omissions make it harder to evaluate the comparability of the groups, the completeness of follow-up, and the robustness of the findings.

The study description identifies respiratory infections and related care as additional interests, but no secondary results are posted. The record therefore does not support conclusions about those outcomes. The safety entries report no serious or other adverse events in the listed participants, but the record’s limited safety detail and small groups do not establish the absence of risk.

Overall, the posted data document a statistically notable difference in the primary outcome distributions for this trial. They do not answer every question about the intervention’s effects, clinical relevance, safety, or performance in other populations. Interpretation should remain tied to the measured endpoint, the recorded participants, and the limits of the registry information.

14. Why This Trial Matters Statistically

This trial is statistically informative because it illustrates the difference between a test result and an effect estimate. The registry reports a Wilcoxon (Mann-Whitney) p-value of <0.001, alongside group medians and inter-quartile ranges. The p-value indicates evidence against the test’s null hypothesis, while the summaries describe observed values within each group. Neither component supplies a confidence interval for the between-group contrast, which would help communicate uncertainty in the estimated effect.

The use of medians and inter-quartile ranges also highlights that clinical outcome distributions may not be well described by a mean and standard deviation alone. A rank-based comparison can be useful for comparing groups without requiring normally distributed measurements. Yet a rank test does not automatically answer whether the medians differ; its interpretation depends on the distributions and assumptions. Clear reporting of the effect measure, test assumptions, and uncertainty would make the result easier to interpret.

The registry record also illustrates why enrollment and analysis populations should be distinguished. The trial recorded enrollment of 21, and the posted outcome summaries include 11 participants in one group and 10 in the other. Without participant flow and missing-data information, readers cannot determine whether the analysis included all randomized participants or whether outcome availability affected the comparison.

Finally, the study description names additional clinical questions, while only the primary outcome result is posted. Reporting the status and results of all prespecified outcomes, along with the statistical plan and safety definitions, is important for understanding the scope of evidence. These details are not reported in the registry record. The trial therefore offers a clear primary comparison but leaves meaningful questions about precision, completeness, and the broader outcome set unanswered.

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 recorded enrollment was 21, which limits the breadth of information available from the trial and makes estimates potentially sensitive to individual observations. The registry does not report a sample-size justification, so it is not possible to assess the intended precision or the assumptions used to plan enrollment. It also does not provide a confidence interval for the group contrast, leaving uncertainty around the effect size unquantified in the posted analysis.

The population is described broadly as children with neuromuscular diseases. Specific diagnoses, age range, eligibility criteria, baseline disease severity, and respiratory status are not reported in the registry record. Without those details, it is difficult to assess which children the results represent or how similar the enrolled groups were at baseline. Baseline vital-capacity values are also not reported.

The intervention description is incomplete: the exercise-program text is truncated. The registry does state the frequency and duration of sessions and home practice, but does not report adherence, treatment fidelity, or variation in delivery. The usual-therapies group is described as receiving no physiotherapy approach to respiratory difficulties, while the content of other usual care is not specified. This limits understanding of the contrast between groups.

Although the trial is described as having a blinded evaluator, the registry does not state who was masked or how masking was maintained. Randomization procedures and allocation concealment are not described. The participant flow, analysis population, missing-data methods, and protocol are not reported, so risks related to attrition, selective analysis, and departures from prespecified methods cannot be assessed.

The result is reported for one primary endpoint, with no secondary outcome results posted. The registry does not describe multiplicity handling, sensitivity analyses, or the clinical importance threshold for vital-capacity change. Safety reporting is also limited: event terms and deaths are not fully characterized, and the collection procedures are not described. These limitations apply to what can be learned from the registry record and do not establish that the underlying trial lacked additional documentation.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effectiveness of Respiratory Physiotherapy in Children With Neuromuscular Disease — NCT02743702.
• Registry record last updated 2016-07-11; status last verified 2016-05.
• Results first posted 2016-07-11.
• 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

The completed randomized parallel-group trial studied respiratory physiotherapy versus usual therapies in children with neuromuscular diseases. The registry records enrollment of 21 and identifies University of Seville as sponsor. The primary outcome was percentage change from baseline vital capacity at one year, measured by spirometer.

The median change was 33.33 in the respiratory physiotherapy group, with an inter-quartile range of 11.11 to 89.74. In the usual-therapies group, the median was -7.41, with an inter-quartile range of -15.6 to -3.82. The reported Wilcoxon (Mann-Whitney) comparison had p < 0.001. The registry does not report a between-group effect estimate or confidence interval.

No secondary outcome results are posted. The record does not report the analysis population, missing-data handling, sample-size justification, or full statistical plan. Safety entries list no serious or other adverse events among participants at risk in either group; deaths are not reported as a count. These results describe the registered record and leave important questions about precision and completeness unresolved.