Oral Amino Acid Nutrition to Improve Glucose Excursions in PCOS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Oral Amino Acid Nutrition to Improve Glucose Excursions in PCOS (NCT03717935), a randomized na study. The primary outcome is Hepatic Fat Fraction.

2. Clinical Question

3. Trial Design

This was a randomized, quadruple-masked crossover trial with enrollment of 27. Its status is completed. The registry lists the phase as not applicable. In a crossover design, participants receive interventions in separate periods, so each participant may contribute measurements under more than one treatment condition. This can allow a within-participant comparison, but the registry record does not report the sequence allocation, the number of participants who completed each period, or how the analysis accounted for repeated measurements.

The interventions were an essential amino acid supplement and placebo. Each was described as a 4-week intervention, with 15g 2/day. The primary endpoint timeframe refers to measurement 4 weeks after completing the first intervention and approximately 8 weeks later, after 4 weeks of washout and 4 weeks of the second intervention. The record therefore indicates a washout between periods. It does not report whether the planned washout was sufficient to prevent carryover or how any possible period or sequence effects were evaluated.

The primary outcome was hepatic fat fraction measured by MRI and calculated with the Dixon method as proton density hepatic fat fraction. The record describes the outcome as a median with inter-quartile range. Secondary outcomes covered hepatic and whole-body metabolism, adipose insulin sensitivity, sleep, apnea hypopnea index, and amino acid levels. The record lists 11 outcome measures, but reports zero analyses. It does not provide the statistical analysis plan, analysis population, missing-data approach, or outcome estimates. Thus, the design and intended measurements can be described, but the treatment comparison cannot be reconstructed from the registry record.

4. Participant Flow and Accounting

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

Before assignment: This was a crossover study. There were a total of 27 participants enrolled in the study. Four participants were never randomized: 3 screen failed and 1 of withdrew. Two participants withdrew after completing the placebo phase of the study

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: adolescent girls with PCOS

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 Hepatic Fat Fraction, measured over 4 weeks after completing the first intervention, and approximately 8 weeks later (4 weeks washout and 4 weeks of second intervention).

The primary endpoint was hepatic fat fraction, expressed as percent hepatic fat. The registry describes it as an MRI measure calculated with the Dixon method as proton density hepatic fat fraction, with a stated range of 0-75%. It identifies values greater than 5% as extra fat. The endpoint was measured after the placebo and amino acid therapy periods, following the timing described for the crossover design.

Hepatic fat fraction is used to quantify the proportion of liver tissue represented by fat, giving a direct imaging-based measure of hepatic fat rather than a general description of liver appearance. As a continuous measurement, it can capture differences across a range of values. The registry record specifies a median and inter-quartile range as the summary format, which describes the central value and spread without assuming a symmetric distribution. This is relevant because biological measurements may be skewed or include values that are not well represented by a mean and standard deviation.

The endpoint fits the stated aim of examining hepatic fat and glucose metabolism in girls with PCOS and hepatic steatosis. However, a measurement definition alone does not establish what happened during either treatment period. Comparative values, the within-participant contrast, and a measure of uncertainty are not reported in the registry record. The endpoint therefore identifies what investigators intended to measure, not an estimate of the supplement's effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods can clarify how a treatment comparison should be read, but the registry record does not report the analysis methods used for this trial. The following concepts are general explanations, not descriptions of an unreported protocol or analysis.

What does a crossover design change?

In a parallel-group trial, each participant is usually assigned to one treatment group. In a crossover trial, participants receive treatment conditions in separate periods. Measurements from the same participant are correlated because they share that participant's characteristics. A comparison that treats all measurements as unrelated can misrepresent uncertainty. General crossover analyses therefore account for within-participant pairing. They may also assess period effects, sequence effects, and carryover, depending on the design and the analysis plan. The registry describes a randomized crossover model and a washout, but it does not report the analysis model, sequence details, or assessments of these effects.

Carryover refers, in general, to an effect of an earlier treatment that remains into a later period. A washout period is intended to separate treatment periods, but its presence alone does not demonstrate that carryover was absent. The record describes 4 weeks of washout in the primary endpoint timeframe. Whether carryover was assessed or how it might affect the comparison is not reported in the registry record.

What does the median and inter-quartile range communicate?

The primary outcome is specified as a median with inter-quartile range. In general, the median is the middle of an ordered set of observations. The inter-quartile range describes the spread of the middle half of those observations. These summaries can be useful when measurements are skewed or when extreme values make a mean and standard deviation less representative. They describe the distribution within a treatment period; a treatment effect still requires a defined comparison between periods.

For paired data, the distribution of individual within-participant differences may be important in addition to separate period summaries. General statistical practice distinguishes an estimate of the treatment contrast from a description of each condition. The registry record does not report participant-level differences, a contrast estimate, or an uncertainty interval, so readers cannot assess the paired comparison from the listed endpoint definition.

How should uncertainty be understood?

In general, a confidence interval is a range of values compatible with the data and the statistical model at a stated confidence level. It conveys both the estimated effect and its precision. A narrow interval indicates greater precision than a wide interval, while an interval that includes values on different sides of no difference can be compatible with more than one interpretation. The registry record reports no confidence interval for the primary comparison. It also reports no p-value. Without these statistics, neither the size nor the precision of an estimated treatment difference can be evaluated.

A p-value, in general, describes how incompatible data are with a specified null hypothesis under the assumptions of a statistical model. It is not the probability that a treatment works or that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. No p-value is reported for this trial's primary endpoint.

Why does the outcome distribution matter?

General statistical methods should match the type and distribution of the measurements. A median-based summary may suggest that investigators considered a distribution for which a median was informative, but it does not identify the test or model used. The record does not report a distributional assessment, transformation, or nonparametric method. It is therefore not possible to infer the analytic procedure from the choice of summary statistic alone.

Over-dispersion is a general issue in data where variability is greater than a model assumes. If it is not handled appropriately, standard errors and uncertainty estimates may be misleading. The posted information does not indicate whether over-dispersion was relevant to any outcome or whether a method addressing it was used. This is a general consideration, not a claim that the trial's data were over-dispersed.

What can planning calculations establish?

Sample-size planning calculations are assumptions-based illustrations of how much information a future comparison might require under a specified effect size, significance level, allocation, and statistical approximation. They are not observed power and do not establish that a completed study had adequate precision. The registry record does not report the trial's own sample-size justification. It also does not report a primary outcome effect estimate from which readers could judge the magnitude used in any planning illustration. Any planning values should therefore be read as planning quantities, not as evidence about the observed treatment comparison.

For this trial, enrollment was 27, but enrollment is not equivalent to the number analyzed. The number contributing data to each period, the handling of incomplete crossover sequences, and the analysis population are not reported in the registry record. These details matter to the amount of information available and to the validity of a paired analysis.

Overall, the general statistical concepts explain what would be relevant to interpreting a crossover comparison of hepatic fat fraction. They do not fill the information gaps in the record. The analysis model, treatment contrast, uncertainty estimate, and analytic population are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 11 outcome measures, including the primary hepatic fat fraction outcome and secondary measures related to metabolism, insulin sensitivity, sleep, and amino acid levels. It reports zero analyses. The record does not identify which outcomes were analyzed, give estimates for them, or state whether any outcome was designated as a secondary or exploratory analysis in the statistical plan.

Multiplicity arises when several outcomes or comparisons are tested. In general, the more statistical tests considered, the greater the chance that at least one result may appear notable by chance if no adjustment or prespecified strategy is used. Methods for managing multiplicity can include a hierarchy of outcomes, adjustment of significance thresholds, or explicit treatment of secondary findings as exploratory. These are general options, not methods documented for this trial. Whether multiplicity adjustment was used is not reported in the registry record.

The registry record does not report how missing outcome measurements were handled, whether participants with incomplete treatment periods were included, or which analysis population was used. In a crossover trial, missing measurements in either period can affect which paired comparisons are available. Excluding incomplete cases, using a model that accommodates available measurements, or applying another method can lead to different assumptions. No particular approach can be attributed to this trial.

The number enrolled does not reveal the number with complete outcome data. The record does not report withdrawals, exclusions, reasons for missingness, or the number analyzed for the primary endpoint. These omissions limit assessment of selection bias and precision. The statistical analysis plan and its prespecification status are also 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 0% reporting threshold.

The registry reports that 27 participants were at risk for serious adverse events and 27 were at risk for other adverse events. It records 0 participants affected in each of those categories and 0 deaths. No top serious adverse-event terms are listed. These are the counts recorded for the EAA supplement versus placebo group.

A zero count means that the registry lists no affected participants in that category; it does not establish that the intervention has no risk. Counts should be interpreted in relation to who was monitored, what events were collected, and over what period. The record does not report further details about event definitions, surveillance procedures, attribution to treatment, or the timing of safety collection. It also does not provide event-level descriptions beyond indicating no top serious terms.

The at-risk counts are not comparative estimates of safety, and no rate or between-treatment contrast is reported. In a crossover design, participants may be exposed to both treatment conditions, so interpreting event counts by treatment period can require information about exposure and attribution. Those details are not reported in the registry record. The figures therefore describe the recorded counts, not a complete assessment of relative safety.

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

The record establishes that a randomized, quadruple-masked crossover trial was conducted to examine essential amino acid supplementation and placebo in adolescent girls with PCOS, obesity, and hepatic steatosis. Each intervention was described as lasting 4 weeks, and the primary outcome was hepatic fat fraction measured by MRI. These details show the intended comparison and the type of measurement selected for the trial.

The record does not establish whether hepatic fat fraction was higher, lower, or similar after EAA supplementation compared with placebo. It contains no reported primary outcome values, treatment contrast, confidence interval, or p-value. It therefore cannot support a statistical conclusion about the observed effect or its precision. The absence of reported results should not be interpreted as evidence that there was no effect, just as the trial's stated aims do not establish that there was an effect.

The same caution applies to the listed secondary outcomes. Their inclusion indicates outcomes the study intended to assess; it does not indicate that data were complete or that any particular result was found. The record reports zero analyses, and no secondary outcome estimates are reported. The registry record also does not report a sample-size justification or the analysis population, which limits interpretation of how much information was available.

The serious adverse-event counts record 0 affected participants and 0 deaths among 27 at risk, with 0 affected for other adverse events among 27 at risk. These counts are descriptive, and they do not prove that there is no risk. Additional information about event ascertainment and treatment attribution is not reported in the registry record.

In short, the registry documents a clinical question and a crossover design, but not the results needed to answer that question statistically. It is possible to describe what was measured and how the study was structured; it is not possible to infer the direction, magnitude, precision, or clinical importance of a treatment effect from the reported information.

13. Why This Trial Matters Statistically

This trial is statistically notable because its crossover structure makes the within-participant comparison central to interpretation. When the same person is measured under more than one treatment condition, the analysis must respect the relationship between those measurements. That design can be informative, but readers need to know how the treatment periods, sequence, and potential carryover were handled. The registry record describes randomization, quadruple masking, a crossover model, and a washout period, but does not report the analysis used to account for these features.

The primary measure is an imaging-based hepatic fat fraction, reported in the registry as a median with inter-quartile range. This emphasizes the importance of distinguishing outcome summaries from a treatment-effect estimate. Separate distributions for each condition would not by themselves show the paired contrast or its precision. A clearly reported estimate and uncertainty measure would be necessary to judge how compatible the data are with different possible effects.

The record also illustrates why a completed status and an enrollment count are not substitutes for posted results. Enrollment was 27, yet the registry does not report the number analyzed, outcome values, or comparative estimates. The list of 11 outcome measures makes it important to understand prespecification and multiplicity, but the record does not describe the analysis plan or adjustments.

Finally, the trial's stated focus on hepatic glucose and fat metabolism is broader than its registered primary endpoint alone. The endpoint and secondary outcome list indicate multiple domains of interest, but without analyses the consistency, precision, and relative importance of any findings cannot be assessed. Statistically, the central lesson is that design information explains how a study intended to generate evidence; it does not replace the outcome results and analysis details required to evaluate that evidence.

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.

The main limitation for statistical interpretation is that comparative primary outcome results are not reported in the registry record. There are no treatment-period medians, inter-quartile ranges, effect estimates, confidence intervals, or p-values. The record reports zero analyses, leaving the primary comparison unanswered by the posted information.

Although enrollment was 27, the number of participants who completed both treatment periods or contributed data to the primary analysis is not reported. Withdrawals, exclusions, missing measurements, and the analysis population are also not reported. This prevents assessment of the amount of usable information and whether missing data could have affected the comparison.

The crossover design makes details of treatment sequence, period effects, and carryover relevant, but these are not described in the registry record. The timeframe specifies 4 weeks of washout, but the record does not report whether carryover was evaluated. The statistical model and its assumptions are not reported, so the handling of within-participant correlation cannot be assessed.

The registry lists 11 outcome measures but does not report results or describe multiplicity management. The prespecified analysis plan, sample-size justification, and any interim analyses are not reported in the registry record. These omissions limit assessment of whether analyses followed a plan and how the study was intended to control uncertainty across outcomes.

The adverse-event counts are also limited as a safety description because event definitions, collection methods, timing, and attribution are not reported. The recorded zero counts should be read as registry counts, not as proof that adverse events cannot occur. The primary endpoint description and trial status provide useful design context, but they do not resolve these gaps in the outcome and methods reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Oral Amino Acid Nutrition to Improve Glucose Excursions in PCOS — NCT03717935.
• Registry record last updated 2025-03-24; status last verified 2025-03.
• Results first posted 2025-03-24.
• 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 record describes a completed, randomized, quadruple-masked crossover trial with enrollment of 27. It compared a 4-week essential amino acid supplement, described as 15g 2/day, with a 4-week placebo, also described as 15g 2/day, in adolescent girls with PCOS. The primary endpoint was hepatic fat fraction measured by MRI using the Dixon method and summarized as a median with inter-quartile range.

The record lists 11 outcome measures and zero analyses. Comparative primary and secondary outcome results, the statistical analysis plan, the analysis population, and missing-data methods are not reported in the registry record. Serious adverse events affected 0 of 27 at risk, other adverse events affected 0 of 27 at risk, and deaths were 0. These counts do not establish absence of risk or substitute for comparative outcome results.