Musculoskeletal Plasticity After Spinal Cord Injury: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Musculoskeletal Plasticity After Spinal Cord Injury (NCT02622295), a non-randomized na study. The primary outcome is Acute Gene Regulation: MSTN.

2. Clinical Question

3. Trial Design

The registry describes a parallel, non-randomized study with no masking. It lists enrollment as 71 and status as completed. The listed start is 2015-05, and primary completion is dated 2021-11-18. The phase is recorded as not applicable. These administrative fields describe the study record; they do not establish how many participants completed each intervention or contributed to any particular analysis.

The record distinguishes an acute gene-regulation arm from a training study. The acute arm examines adaptations in gene regulation after single-session electrically induced exercise. Its primary listed endpoint is MSTN expression measured 3 hours after stimulation. The training study examines gene regulation, metabolic markers and subject-report measures in response to up to 3 years of electrically induced exercise. The study summary describes comparisons between HF and LF active-resisted stance for the training aims, including systemic markers of metabolic health and bone turnover. EQ-5D is listed as a secondary subject-report outcome.

Because allocation is non-randomized, differences between groups may reflect factors other than the exercise frequency or intervention. The registry itself cautions that the arms are not a like-for-like control comparison. The record does not report the allocation process, baseline comparability, participant flow, adherence, co-interventions or whether any adjustment was used to address group differences. Those omissions limit interpretation of the comparison, even if an outcome estimate were available.

The registry lists 13 outcome measures and 13 analyses, but the detailed results for the primary endpoint are not reported in the registry record. The record also does not report the statistical analysis plan, analysis populations or methods for handling missing data. The planned and completed study dates and the completed status therefore do not, by themselves, show which analyses were completed or what their findings were.

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 Acute Gene Regulation: MSTN, measured over 3 hours after a single session of electrical stimulation.

The primary listed endpoint is acute post-stimulation skeletal-muscle myostatin (MSTN) expression. It is measured from a muscle biopsy using exon array analysis, with the assessment scheduled 3 hours after a single session of electrical stimulation. The registry describes the outcome as a continuous measure summarized by a mean and standard deviation, in arbitrary units.

The measure is intended to capture gene-expression response in skeletal muscle following stimulation. The registry explains that the array values are processed using robust multichip average, including background correction, quantile normalization, log2 transformation and median polish probe-set summarization. It states that 0 represents no mRNA expression and that higher values represent greater expression compared with all genes in the microarray. These details describe the scale and processing of the endpoint, not the size or direction of any study effect.

MSTN is relevant to the study’s focus on muscle adaptation and gene regulation. The study summary frames gene regulation as one way to examine whether electrically induced exercise is associated with a shift toward an oxidative muscle phenotype. The record does not report the observed MSTN means, standard deviations, group contrast, confidence interval or p-value. It also does not report evidence that a change in this endpoint corresponds to a change in metabolic health or a patient-reported outcome. The registry’s rationale should therefore be distinguished from a demonstrated clinical consequence.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical details available in the registry record are limited. The primary endpoint is continuous and is described using a mean and standard deviation. The record names the outcome, unit, measurement timing and array-processing steps, but does not report the observed group summaries or inferential results. The interpretation below distinguishes those trial-specific details from general statistical principles.

What does the mean describe?

For a continuous outcome, a mean describes the central level of the measurements in the analyzed group. The standard deviation describes how spread out the measurements are around that mean. In general, reporting both helps readers understand typical values and variability. A mean alone does not show the distribution’s shape, whether measurements are influenced by outliers, or whether groups differ in a way that is statistically or clinically meaningful. Here, the registry identifies mean and standard deviation as the summary format, but the actual MSTN values are not reported in the registry record.

The stated unit is arbitrary units. The registry explains the interpretation of the array scale: 0 represents no mRNA expression, and higher values indicate greater expression relative to all genes in the microarray. That scale description is not a numerical result for either study arm. It also does not, on its own, give a clinically interpretable threshold or indicate what size of change would matter to participants.

How should an estimate and confidence interval be read?

General explanation: an estimated group difference or change is a summary of the data, while a confidence interval conveys the uncertainty around that estimate under the statistical model used. A narrower interval indicates greater precision in that model; a wider interval indicates less precision. An interval that includes values on either side of no difference may be compatible with a range of possible effects, rather than proving that the true effect is exactly zero. The registry does not report a confidence interval for the primary endpoint, so precision cannot be judged.

General explanation: a p-value is a measure of how compatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. No p-value for the primary endpoint is reported in the registry record. Without an estimate and its uncertainty, a significance result alone would not answer how large or precise the difference was; in this record, neither is available.

What does the processing description establish?

The registry says the muscle-biopsy array data were processed using robust multichip average. It lists background correction, quantile normalization, log2 transformation and median polish probe-set summarization as components of that procedure. In general, normalization and summarization methods are used to make array measurements more comparable and to derive probe-set values from the underlying measurements. The record’s description identifies the processing approach, but does not provide quality-control results, details of excluded measurements, batch handling or sensitivity analyses. Those details are not reported in the registry record.

The transformation and normalization description also matters for interpretation: statistical summaries refer to the processed array scale, not necessarily to a directly measured concentration or an absolute quantity of myostatin. The registry describes higher values as greater expression compared with all genes in the microarray. It does not report a conversion from arbitrary units to a biological concentration, nor a clinically meaningful difference threshold.

Why does the non-randomized design matter?

General explanation: random allocation, when used and implemented appropriately, can help balance measured and unmeasured participant characteristics across comparison groups on average. A non-randomized study does not obtain that protection through random assignment. Group differences may therefore reflect baseline characteristics, selection into an intervention, or other factors as well as an intervention effect. Statistical adjustment can sometimes address measured differences, but cannot automatically eliminate unmeasured confounding.

The registry lists allocation as non-randomized and explicitly warns that the arms are not a like-for-like control comparison. It does not report whether groups were adjusted for baseline characteristics, what covariates might have been considered, or whether the primary comparison was within-participant or between groups. Those analysis details are not reported in the registry record. Consequently, the design description supports caution, but does not permit a complete assessment of confounding or the analysis strategy.

What do the planning calculations mean?

The registry describes sample-size planning illustrations based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. The illustrations consider detecting a stated fraction of the observed effect and express results as participants per arm for 80% power. They are planning calculations, not observed power, and they are not reported as the original study’s design rationale. The registry record does not report a sample-size justification used to plan this trial.

General explanation: power is a design-stage probability of detecting an effect of a specified size under stated assumptions if that effect is present. Calculating power after a study from its observed effect does not establish that the study was adequately designed, and is not a substitute for an interval showing uncertainty. The observed-effect basis also means planning illustrations can change with the estimated effect. The numerical illustration results are not reported in the registry record, so they cannot be independently reviewed.

General explanation: over-dispersion occurs when data vary more than a chosen model expects. If present and not accommodated, uncertainty estimates can be too small and inferential conclusions can be misleading. The registry record does not report whether over-dispersion was assessed or relevant to the listed continuous endpoint. This is a general methodological consideration, not a finding about this study.

Finally, the registry lists 13 outcome measures and 13 analyses, but does not report the detailed model specifications or results. The record does not state which outcomes were primary in the analysis plan beyond the listed primary endpoint, how repeated measurements were handled, or whether adjustments were made for multiple testing. These omissions prevent a fuller appraisal of statistical model assumptions and the relationship between the listed aims and reported analyses.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures and 13 analyses. The study’s stated aims span muscle gene regulation, systemic metabolic markers, bone turnover and subject-reported quality of life. Considering multiple outcomes raises a general statistical issue: when many hypotheses are tested, the chance of at least one apparently unusual result can increase. This concern can be handled in different ways, such as defining a hierarchy of outcomes or adjusting inference, but the appropriate approach depends on the analysis plan and research question. The registry record does not report a multiplicity adjustment, testing hierarchy or other approach for interpreting the multiple outcomes.

The primary listed endpoint is acute MSTN expression, while EQ-5D is listed as a secondary outcome. The registry does not report a complete prespecified endpoint hierarchy or clarify how the training-study aims relate to the acute primary endpoint in confirmatory testing. Results for the 13 listed analyses are not reported in the registry record, so it is not possible to determine which analyses were conducted as planned or how any multiplicity strategy affected their interpretation.

Missing-data methods and analysis populations are also not reported in the registry record. The record does not describe the number of participants with available data at each time point, how missing values were handled, whether analyses followed an intention-to-treat or other population definition, or whether sensitivity analyses were performed. Listing enrollment as 71 does not establish the outcome-specific analysis denominators. The adverse-event fields have their own at-risk counts, but these do not establish the number analyzed for the efficacy endpoints.

General explanation: missing data can affect both precision and potential bias, depending on why values are absent and how the analysis handles them. Without outcome-specific participant flow and stated methods, readers cannot determine whether missingness was limited, balanced between groups or addressed under defensible assumptions. Those details are not reported in the registry record.

11. 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.

The registry’s adverse-event fields list the Acute Gene Regulation group with 40 at risk, 0 serious adverse events, 0 other adverse events and 0 deaths. For the Training Study group, the record lists 31 at risk, 0 serious adverse events, 0 other adverse events and 0 deaths. These figures describe the entries in the registry record for the named groups; they do not establish the absence of every possible event.

The at-risk figures are the denominators recorded for these safety fields. They should not be assumed to be the numbers analyzed for the primary endpoint or other outcomes. The record does not report the safety monitoring period, the criteria for collecting events, event severity categories beyond the displayed serious and other classifications, or a detailed account of event ascertainment. It also does not provide descriptions of individual events, because none are listed in the record.

Zero recorded events does not prove that the intervention is free of risk. It means that no events are recorded in these particular fields for the listed groups. The registry record does not report enough information to assess how completely adverse events were collected, whether the same observation period applied to both groups, or whether participants had safety follow-up after intervention. These counts should therefore be read as registry-reported safety data, not as a comprehensive safety assessment or a basis for medical advice.

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

The registry record documents a study focused on muscle gene regulation and broader metabolic and quality-of-life questions in people with spinal cord injury. It identifies an acute MSTN endpoint after a single electrically induced exercise session and describes a separate training study involving up to 3 years of electrically induced exercise. It also states a research rationale involving oxidative muscle phenotype, metabolic health and bone turnover. These descriptions clarify what the investigators set out to study.

They do not establish what the study found. Numerical MSTN results, group-level metabolic results, bone-turnover estimates and EQ-5D results are not reported in the registry record. The record therefore does not show whether measurements increased, decreased or remained similar, nor how uncertain any estimate was. The hypotheses in the study summary should not be mistaken for outcome findings. The completed status and listed dates are administrative information, not substitutes for results.

The record also does not support a causal interpretation of any possible HF-versus-LF difference. Allocation is non-randomized, and the registry cautions that the arms are not a like-for-like control comparison. Baseline group information and analysis methods that might clarify comparability are not reported. The study’s design and record do not establish that any outcome change, if observed, was caused by the exercise approach rather than other differences or influences.

More broadly, a change in a gene-expression measure is not, by itself, evidence of an improvement in a clinical outcome or quality of life. The registry’s stated aims connect these topics as research questions, but the outcome results needed to evaluate those connections are not reported. No claim that an intervention works or does not work follows from the information available in the registry record.

The safety entries are also limited: they list zero serious events, zero other events and zero deaths for each named group, using the recorded at-risk counts. These fields do not establish that there was no risk, and they do not replace a detailed account of safety monitoring. The most defensible reading is that the record describes the study’s questions and methods, while leaving its main statistical findings and their precision unavailable.

13. Why This Trial Matters Statistically

This study raises a useful statistical distinction between an intervention’s biological rationale and evidence about its outcomes. The registry describes a hypothesis that electrically induced exercise may influence skeletal-muscle gene regulation and a broader set of metabolic measures. It also specifies an acute gene-expression endpoint and a longer training study. A well-defined endpoint and processing description help readers understand what was measured, but interpretation still depends on the estimated effects, their uncertainty and the comparison design. Those numerical results are not reported in the registry record.

The non-randomized allocation makes the comparison structure especially important. If groups differ before treatment or enter groups for reasons connected with their outcomes, an observed contrast may combine intervention-related change with those pre-existing differences. The record explicitly warns that the arms are not a like-for-like control comparison. That caution is central to any statistical reading and cannot be resolved simply by knowing the enrollment field or the study’s completed status.

The record also illustrates why analysis transparency matters when a study lists multiple outcome measures and analyses. Readers need to know which outcomes were prespecified as primary, how comparisons were handled, what participant sets contributed data and how missing values were addressed. In this case, the registry lists 13 measures and 13 analyses, but detailed results and several analysis-plan elements are not reported. Without those details, neither selective emphasis nor the robustness of findings can be assessed.

Finally, distinguishing planning illustrations from trial results prevents a common misreading. Calculations based on an observed effect under assumptions are not observed power and do not establish the adequacy of the original design. The statistical value of this registry record is therefore primarily descriptive: it identifies the research questions, measurement approach, design limitations and selected safety counts. It does not provide the outcome estimates required for a conclusion about effect size or precision.

14. 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 specific to this study record constrain interpretation. First, the primary MSTN outcome is described in detail, but its numerical results are not reported in the registry record. Means, standard deviations, group contrasts and uncertainty measures are not available. The same limitation applies to the broader metabolic, bone-turnover and quality-of-life aims. Consequently, neither the direction nor magnitude of study findings can be evaluated.

Second, the record describes non-randomized allocation and explicitly cautions that the arms are not a like-for-like control comparison. It does not report the allocation process, baseline characteristics, adjustment variables or model specifications. This prevents readers from assessing group comparability and the extent to which potential confounding was addressed.

Third, the registry does not report participant flow or outcome-specific analysis denominators. Although enrollment is listed as 71, the record does not show how many participants posted usable data for MSTN or each training outcome. Missing-data handling, analysis population definitions, protocol adherence and sensitivity analyses are not reported. These omissions matter for judging representativeness and precision.

Fourth, the registry lists 13 outcome measures and 13 analyses but does not report a multiplicity strategy or a complete hierarchy of outcomes. Detailed results are also absent, preventing assessment of whether analyses were prespecified, how much uncertainty accompanied estimates, or whether conclusions depended on modeling choices.

Finally, the adverse-event fields contain only aggregate counts for the named groups. The record does not describe the observation period, collection procedures or individual events. It also does not provide clinical thresholds for interpreting the arbitrary-unit gene-expression scale. These record-level omissions should not be read as proof that the study did not collect such information elsewhere; they mean it is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Musculoskeletal Plasticity After Spinal Cord Injury — NCT02622295.
• Registry record last updated 2022-11-04; status last verified 2022-08.
• Results first posted 2022-11-04.
• 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.

18. Record Summary

The registry identifies NCT02622295 as a completed, parallel, non-randomized study with no masking, focused on musculoskeletal plasticity after spinal cord injury. It lists enrollment as 71 and describes an acute gene-regulation arm and a training study of electrically induced exercise. The primary listed endpoint is skeletal-muscle MSTN expression, measured 3 hours after a single stimulation session and summarized as a continuous mean with standard deviation.

The study summary also describes aims concerning HF and LF active-resisted stance, systemic metabolic markers, bone turnover and EQ-5D. The record lists 13 outcome measures and 13 analyses. It reports zero serious adverse events, zero other adverse events and zero deaths for the at-risk groups listed for acute gene regulation and training.

Numerical primary and secondary outcome findings, confidence intervals, p-values, missing-data methods, analysis populations and a detailed statistical plan are not reported in the registry record. The registry cautions that the non-randomized arms are not a like-for-like control comparison. The record therefore describes the study’s questions and design, but does not permit assessment of outcome magnitude or precision.