Historically Controlled Trial of Corticosteroids in Young Boys With Duchenne Muscular Dystrophy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Historically Controlled Trial of Corticosteroids in Young Boys With Duchenne Muscular Dystrophy (NCT02167217), a na phase 2 study. The primary outcome is Bayley III Gross Motor Scaled Score (Change From Baseline to 12 Month).

2. Clinical Question

The rationale in the study summary is that untreated infants and young boys with Duchenne muscular dystrophy may decline in abilities relative to their peers, while treatment at younger ages may be delayed because of concerns about corticosteroid side effects. The investigators planned to assess motor development during weekend corticosteroid treatment. Those points describe the study’s motivation and question; they are not results of the trial’s primary endpoint.

The design makes the distinction between a within-group change and a comparative treatment effect important. A change from baseline describes how the treated group’s scores changed over time. A comparison with historical observations would require suitable historical data and an analysis that accounts for differences between the trial participants and the historical group. Details and results for such a comparison are not reported in the registry record.

3. Trial Design

This is a Phase 2 historically controlled trial, listed as completed. Its allocation is recorded as not applicable, masking as none, and model as single group. The registry lists an enrollment of 25. The study summary describes treatment at five Muscular Dystrophy Association-DMD centers. The listed intervention is oral prednisolone; the arm description specifies 5mg/kg/ day on Friday and Saturday with breakfast.

The study dates recorded are a start date of 2014-04-17 and a primary completion date of 2017-02-22. The primary outcome timeframe is one year, and its title specifies change from baseline to 12 Month. The registry does not describe a concurrent untreated or active-comparator arm. Instead, the study is characterized as historically controlled, so interpretation of any comparative claim would depend on the historical data and comparison methods. Those details are not reported in the registry record.

With no random assignment or masking listed, the design differs from a randomized, blinded comparison. In general, historical comparisons can be affected by differences in participant characteristics, measurement, follow-up, or care between the current study and the earlier observations. These are general design considerations, not reported findings about this particular trial. The registry record does not describe procedures intended to address such differences.

The record lists one outcome measure and no analysis entries. It does not report how participants were selected for analysis, how missing outcome observations were handled, or whether the historical-control comparison was adjusted. Although enrollment is listed, the record does not clarify whether that figure is a target or the number actually analyzed for the primary outcome. The primary endpoint result itself is not reported in the registry record, so the treatment group’s observed change and its precision cannot be assessed from the listed outcome information.

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: We analyzed the change in the gross motor score after one year. An increase indicates improvement compared to peers

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.

Population: Two of the 25 dropped out of study. One was lost to followup within a few months and the second discontinued the study after 6 months.

6. Primary Endpoint

The registry lists the primary outcome as Bayley III Gross Motor Scaled Score (Change From Baseline to 12 Month), measured over One year.

The primary endpoint is the change in Bayley III Gross Motor Scaled Score from baseline to 12 Month. The registry describes the Bayley-III measure as assessing motor development and gives the timeframe as one year. Its population description says that an increase indicates improvement compared with peers. The score is reported in units on a scale, with the outcome parameter specified as a mean and dispersion specified as a standard deviation.

The scale is normed for typically developing children and is described as following a bell-shaped curve, with a mean of 10 +/-3 for children at all ages. The registry notes that lower values are common in boys with Duchenne muscular dystrophy and gives a baseline average score of 4.2 in this study. These details explain the scale’s reference context; they do not provide the follow-up score or the change during treatment. The record does not report the observed mean change, its standard deviation, or an interval estimate.

A change-from-baseline endpoint uses each participant’s starting score as a reference for later measurement. In general, this can describe the direction and size of change over time, but does not by itself establish what would have happened without treatment. For this historically controlled study, interpreting change relative to an untreated course would require the historical data and a valid comparison. The details and result of that comparison are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical details in the registry record are limited. The primary outcome is continuous, its parameter is a mean, and its dispersion is a standard deviation. The record lists one outcome measure and no analysis entries. It does not report a statistical analysis plan, an analysis model, a hypothesis test for the primary outcome, or interval estimates. The explanations below describe general statistical concepts rather than methods confirmed to have been used in this trial.

What does a mean change describe?

A mean summarizes the average value of a continuous measure across the observations included in an analysis. For a change-from-baseline outcome, each analyzed participant’s follow-up score is compared with that participant’s baseline score, and the mean summarizes those changes. A mean can communicate the group’s overall direction and average amount of change, but it does not show how evenly individual changes are distributed. The registry identifies the endpoint as a mean change but does not report its result.

A standard deviation describes spread among individual observations around their mean. It is not the same as the uncertainty in the estimated mean. In general, a larger standard deviation indicates more variability in participants’ values, while the precision of a mean estimate also depends on the amount of usable data. The registry specifies standard deviation as the dispersion measure but does not give the endpoint’s observed standard deviation or the number contributing data.

What would an interval estimate add?

In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis at a stated confidence level. It helps readers assess precision: a narrower interval indicates greater precision than a wider interval, under the same method and confidence level. An interval does not remove bias from a flawed comparison, and it does not guarantee that the true value lies within the particular interval. No confidence interval for the primary endpoint is reported in the registry record.

How does the historical control affect interpretation?

A single-group study can describe change over time in the treated participants. It cannot, from that change alone, separate treatment-related change from other influences such as natural development, changes in measurement, or events occurring over follow-up. A historical control can offer a reference course, but its usefulness depends on whether the historical participants and observations are sufficiently comparable with the current study. General methods might address comparability through eligibility alignment, consistent outcome definitions, or adjustment for measured differences. The registry record does not report which, if any, methods were used in this trial.

Because there is no randomized concurrent control group listed, the comparison is not protected by random allocation between treatment and control groups. In general, this can leave differences between groups that affect the outcome. The record does not provide enough information to judge the magnitude or direction of any such differences. It also does not report historical-control score summaries or a comparative estimate.

What is reported about planning?

The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence of observed power, and the record does not report the numerical planning results. The equal-allocation, two-arm assumption is an illustration and should not be mistaken for the trial’s single-group design. The registry record does not report the trial’s own sample-size justification.

In general, sample-size planning estimates how much information a future study might need under specified assumptions. A planning result depends on the assumed effect, variability, significance level, allocation, and analysis method. If the assumed effect or variability differs from what occurs, the resulting power may differ as well. Planning illustrations do not establish that a completed trial had a particular probability of detecting an effect, and they do not replace the observed estimate and its uncertainty.

What statistical details remain unknown?

The registry record does not report the primary endpoint’s analysis model, test statistic, p-value, confidence interval, adjustment strategy, or treatment of missing observations. It does not describe whether the analysis used all participants, only participants with follow-up measurements, or another population. It also does not report interim analyses or multiplicity procedures. These omissions mean that the planned measurement can be described, but the analytical route from collected measurements to a primary result cannot be reconstructed from the registry record.

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("Oral Prednisolone")
n   <- c(23)
m   <- c(4.8)
sp  <- c(2.3)
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  Oral Prednisolone  23  4.800  2.300  3.805  5.795

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the change in Bayley III Gross Motor Scaled Score from baseline to 12 Month, and no analysis entries. Listing one outcome measure does not establish that the study collected no other outcomes or conducted no other analyses; those details are not reported in the registry record. The record does not describe a statistical plan for controlling multiplicity or identify any secondary or exploratory analyses.

In general, multiplicity arises when multiple outcomes, comparisons, time points, or analyses are considered. Without an approach to multiplicity, the chance of at least one apparently notable result can increase across a set of tests. Whether this issue arose in the analysis of this trial cannot be determined from the registry record. No multiple-testing adjustment or prespecified hierarchy is reported.

Missing-data procedures are also not reported. The registry does not state how missing baseline or follow-up measurements were handled, whether participants who discontinued treatment remained in an analysis, or how incomplete follow-up affected the endpoint estimate. The enrollment figure does not identify how many participants had usable baseline and follow-up scores. It is therefore not possible to assess the amount or potential influence of missing primary endpoint data.

The record does not define an analysis population, such as all enrolled participants or participants with evaluable measurements. It also does not specify whether the primary analysis was based on observed cases or used an imputation or model-based approach. These are not details that can be inferred from the single-group design or the outcome definition. They are not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists the Oral Prednisolone group with 25 at risk for serious adverse events and 0 affected. It also lists 25 at risk for other adverse events and 22 affected. The record reports 0 deaths and does not list any top serious adverse-event terms. These are the adverse-event figures recorded for this group.

The at-risk counts indicate the group size used in the adverse-event listings; they do not establish that every participant had complete safety follow-up for the same duration. The registry record does not describe event definitions, collection procedures, severity grading, duration of observation, or whether participants could contribute more than one event. It also does not provide event-level details for the other adverse events. The counts therefore should not be interpreted as rates of specific event types or as a complete characterization of tolerability.

In general, a reported count of zero serious adverse events means that none are listed as affected in the registry entry; it does not prove that an event is impossible or that treatment is free of risk. Likewise, the count for other adverse events does not establish whether events were caused by treatment. The registry record does not report a comparative safety analysis, and the single-group design offers no concurrent randomized safety comparator. These counts describe the posted adverse-event record, not a causal conclusion.

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

The registry record describes a completed Phase 2, single-group study of oral weekend prednisolone in young boys with Duchenne muscular dystrophy. It identifies a one-year primary endpoint based on change in Bayley III Gross Motor Scaled Score and gives the intended interpretation of the score’s direction. It also records adverse-event counts for the treatment group. These details clarify the question the study set out to address and what safety counts were posted.

The record does not report the primary endpoint result. It therefore does not show the observed mean change, how variable that change was, or how precisely it was estimated. It also does not report a numerical comparison with historical controls. Without those results, the registry entry cannot establish whether scores changed during treatment or how that change compared with the historical course.

Even if a within-group change were available, general statistical reasoning distinguishes change over time from a treatment effect. Participants may change over time for reasons other than treatment, and a historical comparison can be affected by differences between study groups or measurement conditions. The registry record does not give the historical-control data or the methods used to make that comparison. Consequently, no causal conclusion follows from the design description alone.

The safety entries show 0 serious adverse events and 0 deaths listed, alongside 22 participants with other adverse events. These counts are descriptive. The record does not provide event descriptions or a comparative safety analysis, so the figures cannot establish whether an event was caused by treatment or characterize the full range of possible effects.

The appropriate reading is therefore limited: the registry documents the intervention, design, planned endpoint, and recorded adverse-event counts, but does not report the primary outcome findings needed to evaluate the study’s central efficacy question. Missing analysis and follow-up details further limit assessment of precision and robustness.

14. Why This Trial Matters Statistically

This trial illustrates why study design and outcome reporting need to be read together. The primary endpoint is a change in a continuous developmental score, but the study is listed as single group and historically controlled. A within-group change can describe the course of scores among treated participants; establishing how that course compares with what would have happened without treatment requires a credible control reference and a transparent comparison.

Historical controls can be useful when a concurrent control group is not part of a study, but they raise statistical questions about comparability. Differences in participant selection, follow-up, measurement, or background care can affect comparisons. These are general concerns, not findings about this trial. The registry record does not report the historical data or analytical procedures needed to assess them.

The record also demonstrates that an endpoint definition is not the same as an endpoint result. The scale, its direction, and the intended one-year assessment are described, but the observed change and its precision are not reported. Without the estimate and its uncertainty, readers cannot assess the size or stability of the measured change.

Finally, enrollment and adverse-event counts do not fill the gap in outcome reporting. They provide limited context about the registry entry but do not establish how many participants contributed endpoint data or what the primary analysis found. The trial matters statistically because it raises the distinction between describing a treated group and estimating a comparative effect, while the registry record leaves the key outcome estimate unavailable.

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 primary limitation for interpretation is that the registry record does not report the primary endpoint result. It defines change in Bayley III Gross Motor Scaled Score from baseline to 12 Month, but gives no observed change, standard deviation, confidence interval, or test result. The treatment group’s outcome and its precision therefore cannot be assessed from the registry record.

The study is listed as historically controlled, single group, and unmasked, with no randomized concurrent comparison group. The registry record does not report the historical-control outcome data, how those controls were selected, or how comparability was evaluated. It also does not report whether any adjustment was made for differences between the treated participants and historical observations. These gaps prevent assessment of the comparative analysis.

The enrollment listing does not clarify how many participants completed follow-up or contributed primary endpoint data. Missing-data handling and the analysis population are not reported. The record also does not describe the analysis model, statistical test, or interim analyses. Those omissions limit evaluation of the analysis and its robustness.

The adverse-event listing is brief: it includes counts for serious and other adverse events and deaths, but does not provide event terms, definitions, collection procedures, or duration of safety follow-up. The record does not provide a concurrent safety comparison. The counts should therefore be read as registry entries, not as a complete analysis of safety.

Finally, the study summary offers background rationale about untreated development and corticosteroid use, but the registry entry does not include numerical historical outcomes or a reported comparison. Background statements cannot substitute for the trial’s endpoint estimate.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Historically Controlled Trial of Corticosteroids in Young Boys With Duchenne Muscular Dystrophy — NCT02167217.
• Registry record last updated 2018-12-21; status last verified 2018-12.
• Results first posted 2018-05-18.
• 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

NCT02167217 is a completed Phase 2 historically controlled trial of oral prednisolone in young boys with Duchenne muscular dystrophy. The registry lists a single-group design, no masking, and enrollment of 25. The intervention description specifies prednisolone 5mg/kg/ day on two consecutive days, Friday and Saturday with breakfast. The study summary describes participants as under age 30 months and treatment at five Muscular Dystrophy Association-DMD centers.

The primary endpoint is change in Bayley III Gross Motor Scaled Score from baseline to 12 Month, with an increase described as improvement compared with peers. The registry record does not report the observed endpoint result or a historical-control comparison. It lists 0 serious adverse events, 22 participants with other adverse events, and 0 deaths in the treatment group. Analysis methods, missing-data procedures, and analysis populations are not reported in the registry record.