Effects of High-Intensity Interval Training Exercise in Adolescents With Hepatosteatosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of High-Intensity Interval Training Exercise in Adolescents With Hepatosteatosis (NCT04342390), a randomized na study. The primary outcome is Intrahepatic Triglyceride (IHTG).

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. Its stated enrollment is 40. The two groups are the Exercise Group and Control Group. Participants in the Exercise Group were asked to complete four weeks of high-intensity interval training; the Control Group did not undergo HIIT exercise training during the study. The registry record marks the study as completed.

The primary endpoint is intrahepatic triglyceride percentage, with a four-week timeframe. For the posted endpoint summaries, the Exercise Group has a reported group size of 31, a mean of 5.26, and a standard deviation of 3.01. The Control Group has a reported group size of 6, a mean of 8.97, and a standard deviation of 6.61. The record does not explain the relationship between these endpoint group sizes and the stated enrollment, nor does it report why endpoint data are unavailable for any enrolled participants. Those reasons should not be inferred from the group summaries.

The sponsor is Arkansas Children's Hospital Research Institute. The record identifies secondary outcomes concerning alanine aminotransferase, FibroScan controlled attenuated parameter, FibroScan transient elastogram, and total body fat. It lists seven outcome measures and seven analyses, while four secondary outcomes are posted. Details such as the randomization method, allocation concealment, exercise-session delivery, adherence, and protocol deviations are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

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 Intrahepatic Triglyceride (IHTG), measured over 4 weeks.

Intrahepatic triglyceride (IHTG) percentage is the proportion of the liver measurement attributed to triglyceride. In this trial, the registry says IHTG percentage was measured using magnetic resonance imaging, with a four-week timeframe. It describes the measure as theoretically ranging from 0 to 100 and states that, by definition, an individual has non-alcoholic fatty liver disease when IHTG percentage is at or above 5 percent.

IHTG is used as a measure of liver fat, making it relevant to a study concerning adolescents with hepatosteatosis. The threshold in the registry supplies clinical context for interpreting the scale; it does not turn a group mean into a count of participants above or below that threshold. The posted results give group means and standard deviations, not individual measurements or the number of participants meeting a threshold.

The endpoint is identified as a mean of a continuous measure. A mean describes the group’s average value, while a standard deviation describes how spread out the observed values are around that average. The registry does not report baseline IHTG summaries, individual changes, or an adjusted between-group estimate with a confidence interval. Therefore, the endpoint summaries should be read as the reported group values at the stated timeframe, not as a measure of within-person change or a complete estimate of the comparative effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the reported mean describe?

A mean is the arithmetic average of the observed values in a group. Here, IHTG is a continuous measure, and the registry identifies the reported parameter as a mean. A group mean provides a compact description of the group’s central value, but it does not show the distribution of values, whether there are outliers, or how many individuals fall on either side of a clinical threshold. The posted means are 5.26 for the Exercise Group and 8.97 for the Control Group.

The standard deviation describes the spread of observations around a mean. The posted standard deviations are 3.01 for the Exercise Group and 6.61 for the Control Group. A standard deviation is not the same as a standard error or a confidence interval. It describes participant-level variability in the observed group data; a confidence interval describes uncertainty about an estimated quantity. The registry does not post a confidence interval for the ANCOVA comparison.

What does ANCOVA contribute?

ANCOVA is a method for comparing groups on an outcome while accounting for one or more covariates in a model. In general, covariate adjustment can help make a comparison conditional on the included variables. The registry identifies ANCOVA as the method for the primary comparison, but the covariates, model specification, adjusted estimate, and assumptions are not reported in the registry record. It is therefore not possible to reproduce the sponsor’s adjusted analysis from the reported group summaries alone.

The p-value reported for the ANCOVA is 0.363. In general, a p-value describes how unusual data at least as inconsistent with a null hypothesis would be under the statistical model and its assumptions. It does not measure the probability that the null hypothesis is true, the probability that a result is due to chance, or the clinical importance of a difference. Interpretation is stronger when a p-value is read alongside an effect estimate and confidence interval. Those estimate and interval are not reported for this comparison.

Why are a confidence interval and an effect estimate useful?

An effect estimate expresses the comparison on the outcome’s scale. A confidence interval conveys the uncertainty around that estimate under the method used. Together, they help readers assess both the direction and the range of values compatible with the data. A p-value alone cannot indicate whether the estimated difference is small or large, and it cannot show the precision of that difference. Since the registry does not report the adjusted contrast or confidence interval, the comparative magnitude and precision remain unclear.

Simple unadjusted recalculations from group summaries can sometimes provide a separate descriptive comparison. They are not a substitute for an adjusted sponsor analysis, especially when the sponsor’s model includes covariates that are not specified in the record. No recalculated effect estimate or confidence interval is reported in the registry record. The record also does not provide the information needed to determine whether a recalculation would align with the sponsor’s analysis.

How should variability and group size be considered?

Precision generally depends on both the amount of information and how variable the measurements are. Greater spread can make an estimate less precise, while a larger amount of usable data can improve precision, all else being equal. Those general principles do not permit a precise uncertainty calculation without the relevant analysis details. The endpoint summaries report group sizes of 31 and 6, with different standard deviations. The reasons for these group sizes and the handling of any unavailable endpoint data are not reported in the registry record.

In general, over-dispersion means that variability is greater than a statistical model expects. When that occurs, methods that assume less variability can understate uncertainty and make results appear more precise than they are. The registry does not report an over-dispersion assessment for this continuous endpoint, and the summaries alone do not establish that over-dispersion is present. This is a general statistical consideration, not a finding about this trial.

What do the planning illustrations mean?

Planning illustrations based on an observed effect are not observed power. The stated assumptions for these illustrations are a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. Such scenarios are conditional planning exercises, not evidence that the trial had a particular probability of detecting an effect. The registry record does not report that these illustrations were the trial’s original design calculations, and they should not be interpreted as the trial’s prespecified sample-size justification.

Because the outcome is continuous, planning quantities expressed per arm refer to participants per arm for 80% power when that planning scenario is used. These are hypothetical planning quantities, not observed participant counts. They do not alter the reported endpoint group sizes or supply a missing adjusted effect estimate. The registry does not report a protocol-based sample-size justification, interim analyses, or a full statistical analysis plan.

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("Exercise Group", "Control Group")
n   <- c(31, 6)
m   <- c(5.26, 8.97)
sp  <- c(3.01, 6.61)
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  Exercise Group  31  5.260  3.010  4.156  6.364
CARM  Control Group  6  8.970  6.610  2.033  15.907

11. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as an ANCOVA with p = 0.363. The group summaries report means of 5.26 in the Exercise Group and 8.97 in the Control Group, with standard deviations of 3.01 and 6.61, respectively. Those are descriptive summaries, not the adjusted ANCOVA contrast.

The record does not report the sponsor’s adjusted effect estimate or a confidence interval. It also does not specify the covariates or other model details needed to reproduce the analysis. Accordingly, no recalculated comparison is available in the registry record to set alongside the sponsor’s result. The group means alone cannot recover an adjusted estimate.

A simple unadjusted recalculation, when available, would answer a different question from an adjusted analysis and would not replace the sponsor’s analysis. The registry does not identify a discrepancy between a recalculation and the sponsor’s result. The p-value should therefore be read as the reported result of the sponsor’s ANCOVA, with its estimate and precision unavailable in the record, rather than as a numerical description of the effect’s size.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures and seven analyses, and it lists four secondary outcomes: alanine aminotransferase, FibroScan controlled attenuated parameter, FibroScan transient elastogram, and total body fat. The primary outcome is IHTG percentage. The record does not report how the outcomes were organized into a prespecified testing hierarchy or whether any adjustment was made for multiple comparisons.

When several outcomes or analyses are considered, the chance of obtaining at least one apparently notable result can increase if each is tested separately without accounting for multiplicity. This is a general statistical issue, not a claim that a particular error occurred in this trial. The registry’s ANCOVA p-value for the primary endpoint should be interpreted with the available information; the record does not describe multiplicity procedures that would clarify how it relates to the other analyses. Results for the listed secondary outcomes are not reported in the registry record for this account, so their findings cannot be assessed.

The record does not report the amount or pattern of missing primary-outcome data, reasons for missingness, or the method used to handle missing values. The posted endpoint group sizes are 31 for the Exercise Group and 6 for the Control Group, while stated enrollment is 40. These figures do not explain why endpoint data are unavailable or whether the analysis used all randomized participants. No inference about withdrawals, exclusions, or missing-data assumptions should be drawn from the numbers alone.

The analysis population is not reported in the registry record. It is not specified whether the ANCOVA used all randomized participants, a subset with measured endpoint data, or another defined population. The registry also does not report whether analyses followed assignment regardless of adherence. These omissions limit assessment of how closely the reported estimate, if it were available, would represent the randomized comparison.

13. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The posted safety figures report no serious adverse events in either group and no deaths in either group. For other adverse events, the Exercise Group has one affected participant among 34 at risk, while the Control Group has none among 6 at risk. The record does not report a serious adverse-event term, and it does not provide a term describing the one other event.

These figures describe the registry’s reported counts and denominators; they do not establish whether an event was caused by the intervention. The record does not provide event narratives, severity details for the other event, timing, or an assessment of relatedness. The safety denominators differ from the endpoint group sizes, and the registry does not explain that difference. Safety counts should not be treated as interchangeable with the numbers contributing endpoint measurements.

With the limited event details available, the figures support only a narrow description of what was reported. They do not establish that no other safety events occurred outside the reported categories, nor do they support a broad comparison of safety between groups. The registry record does not report further detail that would resolve these uncertainties.

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

The result addresses a specific statistical question: the primary endpoint was IHTG percentage at the four-week timeframe in a randomized comparison of HIIT with a control condition that did not include HIIT training. The registry reports group means and standard deviations and an ANCOVA p-value. It does not report the adjusted difference or a confidence interval, so the size and precision of the adjusted comparison cannot be established from the record.

The descriptive group means are not a substitute for individual trajectories. The registry does not report baseline means or within-person changes, so the posted results do not show how IHTG changed from the start of the study. Nor do group averages show how many participants were above or below the stated 5 percent threshold. The threshold is a definition for an individual, not a conclusion that can be applied to a group mean as if it were a participant count.

The result does not establish what would happen with a different exercise program, duration, population, or setting. The trial concerns adolescents and a four-week HIIT intervention, and details needed to characterize the exercise sessions or participant eligibility are not reported in the registry record. The findings also cannot be extended from this endpoint to the secondary outcomes, because their results are not reported in the information.

A p-value is not a measure of the probability that the intervention is beneficial, harmful, or ineffective. It also does not express the probability that the reported pattern is due to chance. Interpretation requires attention to the estimated effect, its uncertainty, the analysis population, and the conduct of the study. Several of those details are absent from the registry record.

In short, the posted information supports a description of the reported endpoint summaries and the sponsor’s ANCOVA p-value. It does not provide a complete estimate of the adjusted effect, establish within-person change, or answer broader clinical questions beyond this trial’s stated outcome and timeframe.

15. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between descriptive summaries and an adjusted comparison. The group means and standard deviations communicate the observed endpoint summaries, while ANCOVA is the stated method for the primary analysis. Because the adjusted estimate and confidence interval are not reported, the p-value cannot stand in for the missing effect size or its precision. Readers need both pieces of information to understand how large a comparative difference is and how uncertain it may be.

The record also illustrates why analysis denominators deserve attention. Enrollment is stated as 40, while the endpoint summaries and safety figures use different group sizes. Those numbers are tied to different reported results, and the registry does not explain the differences. Without a participant flow or missing-data account, it is not possible to determine from the record why the denominators differ or which participants contributed to each analysis.

Multiplicity is another relevant issue because several outcomes and analyses are listed. The registry does not report whether the analyses were prespecified in a hierarchy or adjusted for multiple testing. This does not invalidate any particular result, but it limits how confidently results across multiple measures can be interpreted together.

Finally, the stated planning assumptions are not the same as the trial’s original design justification or an observed probability of detecting an effect. Keeping that distinction clear prevents planning scenarios from being mistaken for evidence about the trial’s performance. These statistical considerations make the registry record useful to read carefully, while also defining the limits of what can be concluded from its posted results.

16. 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 trial-specific details needed for a fuller assessment are not reported in the registry record. The randomization sequence and allocation concealment are not described. The trial is listed as having no masking, but the record does not explain whether outcome assessment or image reading was blinded. Details of the HIIT sessions, including frequency, duration, intensity targets, supervision, and adherence, are also not reported.

The relationship between stated enrollment and the reported analysis group sizes is not explained. The IHTG summaries use group sizes of 31 and 6, and the safety summaries use denominators of 34 and 6. The record does not provide participant flow, reasons for missing measurements, withdrawals, exclusions, or the analysis population. It is therefore not possible to assess from these results whether missing data or exclusions could affect the comparison.

The primary analysis is identified as ANCOVA, but the covariates, model specification, assumptions, adjusted estimate, and confidence interval are not reported. Baseline IHTG summaries and within-person changes are not reported either. These gaps prevent reconstruction of the adjusted analysis and limit interpretation of the endpoint means as a comparative effect. No recalculated effect estimate or uncertainty interval is available in the registry record.

The registry lists secondary outcomes and analyses, but the registry entries do not include their results or a multiplicity procedure. Safety reporting gives counts but little detail about the one other adverse event and no serious-event terms. The record also does not report a protocol-based sample-size justification or interim-analysis plan. These limitations are specific to the information available for this trial and should not be filled by assumptions about how the study was conducted.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Effects of High-Intensity Interval Training Exercise in Adolescents With Hepatosteatosis — NCT04342390.
• Registry record last updated 2024-08-22; status last verified 2023-07.
• Results first posted 2024-02-20.
• 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.

20. Record Summary

The registry describes a completed randomized, parallel-group trial with no masking and stated enrollment of 40. It compares four weeks of high-intensity interval training with a control condition that did not undergo HIIT during the study. The primary endpoint is IHTG percentage measured by MRI at the four-week timeframe.

Reported endpoint means are 5.26 for the Exercise Group and 8.97 for the Control Group; standard deviations are 3.01 and 6.61, respectively. The sponsor’s ANCOVA is reported with p = 0.363. An adjusted effect estimate and confidence interval are not reported in the registry record. The record also lists secondary outcomes, but their results are not included in the available information.