Evaluation of the Attenuation by Aes-103 of Hypoxia Mediated Decrements in Endurance Exercise Performance: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of the Attenuation by Aes-103 of Hypoxia Mediated Decrements in Endurance Exercise Performance (NCT01871142), a randomized phase 1, phase 2 study. The primary outcome is Primary Objective Endurance Exercise Performance.

2. Clinical Question

The central dose comparisons are the differences between each Aes-103 condition under hypoxia and placebo under hypoxia. The normoxia placebo condition supplies context about performance under normal rather than low oxygen. These are distinct questions: comparing placebo conditions describes the observed difference between oxygen settings, while comparing Aes-103 with hypoxia placebo describes the observed differences between intervention conditions under hypoxia. The registry record identifies safety and tolerability as a secondary objective. It does not report a broader clinical question about preventing acute mountain sickness or other illness as an outcome of this trial.

3. Trial Design

The registry record identifies a randomized, triple-masked crossover study, listed in phases 1 and 2. The study is marked completed. Its enrollment is recorded as 12, and its listed start and primary completion are 2013-03 and 2013-06. Colorado State University is named as sponsor.

In a crossover design, participants are assigned to receive more than one study condition in sequence, rather than remaining in only one condition throughout. The record describes randomized ordering of four conditions: placebo before exercise in normoxia; placebo before exercise in hypoxia; 1000 mg Aes-103 before exercise in hypoxia; and 3000 mg Aes-103 before exercise in hypoxia. It states that each intervention was separated by a 7 day washout period. The registry names the masking as triple, but the specific roles or procedures encompassed by that masking are not reported in the registry record.

The primary outcome lists 11 participants for each of the four conditions. Those counts are not identical to the total enrollment figure, and the record does not explain the difference. The safety groups have denominators of 11 or 12, depending on condition. The record does not state whether all participants completed every condition or describe the analysis population used for each outcome.

The registry record lists hypoxia as the condition of interest. It describes the exercise assessment as a time trial on a stationary cycle ergometer, with testing after the intervention or placebo had been consumed for 1 hour. The specific procedures for generating the random sequence, maintaining masking, assessing carryover, and handling the washout period 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.

Population: Baseline characteristics were analyzed for all subjects that completed study.

6. Primary Endpoint

The registry lists the primary outcome as Primary Objective Endurance Exercise Performance, measured over The time trial will begin after 1 hour after consumption of the intervention or placebo under normoxic or hypoxic conditions..

The primary endpoint is endurance exercise performance measured as time-trial performance on a stationary cycle ergometer, with results expressed in minutes. The description specifies four conditions: placebo in normoxia, placebo in hypoxia, 1000 mg Aes-103 in hypoxia, and 3000 mg Aes-103 in hypoxia. The assessment took place after 1 hour following consumption of the intervention or placebo.

A continuous measure such as time in minutes can preserve distinctions in the measured performance rather than reducing the result to a yes-or-no event. The registry reports the mean for each condition and its standard error. The mean gives the average time recorded in that condition; the standard error describes uncertainty around the estimated mean. It is not the same quantity as the spread of individual participants’ measurements.

In general, an endurance exercise time trial is used to quantify performance under a defined exercise task. In this study, comparing placebo conditions across oxygen settings describes performance under normoxia versus hypoxia, while comparisons of Aes-103 with placebo under hypoxia address differences between those intervention conditions in the low-oxygen setting. These outcomes concern the recorded exercise task and timeframe. They do not, by themselves, measure adaptation to altitude, illness, or longer-term health outcomes.

The registry record does not report an endpoint threshold or a clinically meaningful difference for the time measure. It also does not report additional details such as the trial distance or workload, how the time trial was standardized, or the original statistical model used to analyze repeated measurements.

7. Results Posted in the Registry

• Palcebo + Normoxia: mean 22.40 versus 24.50 on control; difference -2.10 (95% CI -3.79 to -0.41), standardized effect d = -1.04; z-test p = 0.015.
• 1000mg Aes-103 + Hypoxia: mean 24.00 versus 24.50 on control; difference -0.50 (95% CI -2.19 to 1.19), standardized effect d = -0.25; z-test p = 0.561.
• 3000mg Aes-103 + Hypoxia: mean 24.60 versus 24.50 on control; difference 0.10 (95% CI -1.43 to 1.63), standardized effect d = 0.05; z-test p = 0.898.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous and is reported as a mean in minutes with a standard error. A mean summarizes the average outcome in a group or condition. A standard error describes how much the estimated mean would tend to vary across repeated samples under a statistical model. It is not a description of the range of individual participant times. The registry does not report standard deviations for the primary outcome groups.

For each condition, the posted mean and standard error are: 22.4 minutes and 0.7 for placebo in normoxia; 24.5 minutes and 0.5 for placebo in hypoxia; 24.0 minutes and 0.7 for 1000 mg Aes-103 in hypoxia; and 24.6 minutes and 0.6 for 3000 mg Aes-103 in hypoxia. Each outcome group is listed with 11 participants. These descriptive summaries are useful for understanding the scale and direction of the observed values, but they do not account by themselves for the crossover design or for the relationship between measurements from the same participant.

The reported mean differences compare each listed condition with placebo under hypoxia. They are presented as unadjusted comparisons with confidence intervals and p-values. In general, an unadjusted comparison is not corrected for multiple testing or adjusted for other covariates. The registry record does not identify an original model, covariate set, or procedure for analyzing repeated observations. It also does not report whether any analysis accounted for within-participant pairing, period effects, sequence effects, or carryover. Those details matter in a crossover study because outcomes measured from one participant are generally not independent in the same way as outcomes from different participants.

A confidence interval gives a range of values reasonably compatible with the data under the assumptions of its calculation. For these differences, the 95% intervals describe uncertainty around the estimated mean differences. An interval containing zero does not establish that the conditions are identical; it indicates that the data do not rule out zero difference at the interval’s stated level, while also allowing other values in the interval. The interval’s width is important: a wide interval leaves more uncertainty about the size and direction of the difference.

The p-values are unadjusted: 0.015 for normoxia placebo compared with hypoxia placebo, 0.561 for 1000 mg Aes-103 compared with hypoxia placebo, and 0.898 for 3000 mg Aes-103 compared with hypoxia placebo. In general, a p-value summarizes how unusual data at least as discrepant as those observed would be under a specified null model. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of a difference. Since the record does not describe the analysis model, the p-values should be understood as the posted unadjusted summaries rather than evidence of a documented trial analysis plan.

The study has several comparisons involving a shared placebo-under-hypoxia condition. In general, when several hypotheses are tested, the chance of at least one false-positive finding can increase if each test is interpreted separately at the same threshold. Multiplicity procedures can address this concern, but the registry record does not report a correction or a testing hierarchy. The p-values should therefore not be described as adjusted, and a single p-value should not be treated as the sole summary of the evidence.

In general, over-dispersion means that observed variation is larger than a model expects. It can affect standard errors and the reliability of uncertainty estimates when a model assumes less variation than is present. The registry outcome is continuous, and the record does not identify an over-dispersion assessment or a model that would make such an assessment applicable. More broadly, the posted standard errors and summary comparisons do not show how individual observations were distributed.

The record labels the trial as crossover and describes four randomized-order conditions separated by washouts. A paired analysis can use the within-participant relationship across conditions and may be more appropriate than treating condition groups as independent, depending on the actual analysis and available data. The registry does not report participant-level data or a paired estimate, so the posted comparisons cannot be interpreted as a documented paired analysis. The simple comparisons are best read as descriptive, unadjusted calculations based on the reported summaries.

The registry lists one secondary objective, safety and tolerability, and two outcome measures overall. It does not report details of the statistical approach for the secondary outcome. The original sample-size justification, interim analyses, missing-data procedures, analysis populations, and prespecified statistical plan are not reported in the registry record. Without those details, the reported summaries cannot establish whether they follow the original protocol or whether all planned analyses are represented.

10. Confidence Intervals and Precision

The confidence intervals quantify uncertainty around the unadjusted mean differences, rather than around the individual participants’ times. For the normoxia placebo comparison with placebo under hypoxia, the mean difference is -2.1 minutes and its 95% confidence interval is -3.786 to -0.414. This interval lies below zero, indicating that the posted unadjusted estimate and interval are in the direction of a lower mean time under normoxia than under hypoxia placebo. The interval still spans a range of possible difference sizes, so the point estimate should not be mistaken for a precisely known value.

For 1000 mg Aes-103 compared with placebo under hypoxia, the mean difference is -0.5 minutes and the 95% confidence interval runs from -2.186 to 1.186. For 3000 mg Aes-103 compared with placebo under hypoxia, the mean difference is 0.1 minutes and the interval runs from -1.431 to 1.631. Both intervals include zero and allow values on either side of zero. Thus, the posted estimates do not distinguish clearly between a negative and a positive difference.

In general, a narrower confidence interval indicates greater precision under the assumptions used to calculate it; a wider interval indicates more remaining uncertainty about the estimate. Precision depends on factors such as the amount of information and outcome variability. The groups in the primary outcome each have 11 participants, and the intervals for the dose comparisons include a range of possible differences. The record does not provide a clinically meaningful threshold for judging whether any value in these ranges would matter practically.

Because this is a crossover design but the registry does not report the original analysis model, the intervals should be treated as unadjusted summary-based intervals, not as confirmed intervals from a paired crossover analysis. The record does not report a multiplicity adjustment. Accordingly, these intervals describe the posted comparisons and do not resolve uncertainty about the prespecified analysis, repeated-measures structure, or the full set of planned tests.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total event counts: the endpoint is continuous, so the figures refer to participants rather than events. Each planning comparison uses the observed mean difference for that comparison as a reference, with additional rows considering 75% and 50% of the observed effect. Smaller effects require more participants to detect under the same planning assumptions.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is the stated fraction of the observed effect. These assumptions describe a planning illustration based on the observed differences; the trial’s own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column gives an illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect if that effect is truly present, under the stated assumptions. The 90% power column uses a higher target chance of detection and therefore generally requires more participants for the same effect size. The values can differ greatly among comparisons because the observed differences differ in size. When the effect used for planning is reduced to 75% or 50% of the observed effect, the corresponding participant requirements rise.

These figures are planning illustrations, not a description of the actual enrollment required by the crossover protocol. They assume equal allocation between two arms and do not document adjustments for the study’s repeated-condition structure. They are not observed power. Observed power is not a useful substitute for examining the estimates, confidence intervals, and design assumptions after data collection; the planning figures instead show how hypothetical study size changes with the target effect and power level.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -2.100; pooled standard deviation σ = 2.017.
2. n = 2 × (1.96 + 0.842)² × 2.017² / -2.100² = 14.5, rounded up to 15 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -2.1                      # observed difference in means
sigma <- 2.0174241001832                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1871142)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 15 (80% power), 20 (90% power)
 75% of observed effect: n per arm = 26 (80% power), 35 (90% power)
 50% of observed effect: n per arm = 58 (80% power), 78 (90% power)
power.t.test: 15.5 
Simulated power at n = 15 per arm: 0.787 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary objective of endurance exercise performance and a secondary objective of safety and tolerability. The primary performance outcome is reported for four conditions, with three comparisons against placebo under hypoxia in the posted summaries. Because the comparisons share a reference condition, interpreting each unadjusted p-value as an isolated test can understate the uncertainty associated with considering multiple comparisons.

The record does not report a multiplicity adjustment, a hierarchy among comparisons, a primary contrast designated for formal testing, or a statistical analysis plan. The p-values are unadjusted. It is therefore not possible from the registry record to determine whether the trial’s original analysis addressed multiplicity or how any planned tests were intended to be interpreted. The posted results should be read as separate unadjusted comparisons, rather than as an established familywise testing procedure.

The registry lists zero analyses, and it does not describe an analysis population such as all randomized participants, all participants who received an intervention, or participants with complete outcome data. The primary-outcome groups each list 11 participants, while total enrollment is 12. The record does not explain the difference, identify missing measurements, report exclusions, or state how missing data were handled. As a result, it is not possible to determine whether all enrolled participants contributed data to each condition or whether the same participants contributed to every comparison.

For a crossover trial, missing measurements can affect the available within-participant comparisons and the balance of sequence or period information. The record does not report whether missing observations were imputed, whether participants with incomplete sequences were included, or whether sensitivity analyses were conducted. The specific analysis population, missing-data methods, interim analyses, and original statistical plan are not reported in the registry record. These omissions limit interpretation of how the posted summaries relate to the trial’s prespecified analysis and of how robust the comparisons are to incomplete data.

14. 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.

Most frequent non-serious adverse event terms

The registry reports serious adverse event counts of zero in each listed condition: placebo in normoxia, placebo in hypoxia, 1000 mg Aes-103 in hypoxia, and 3000 mg Aes-103 in hypoxia. The numbers at risk are 11, 12, 11, and 12, respectively. The record also reports zero other adverse events in the first three conditions and one other adverse event in the 3000 mg Aes-103 condition, where 12 participants are listed at risk.

These are counts within the registry’s condition groups. The record does not identify the nature of the one other adverse event, provide event-level descriptions, or report whether it was considered related to an intervention. Death counts are not reported in the registry record. The numbers at risk differ across conditions, and the record does not explain the difference or describe how events were attributed when participants received multiple conditions in the crossover.

Zero recorded serious events in these groups does not establish that the interventions have no safety risks. The study enrollment is small, and the registry record provides only the listed counts, without additional detail on duration of follow-up or event ascertainment. These figures describe what the registry reports; they are not a basis for medical advice or broad safety conclusions.

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

The posted results show mean exercise time in four conditions in healthy adult men: placebo under normoxia, placebo under hypoxia, and two Aes-103 doses under hypoxia. The placebo condition means were 22.4 minutes in normoxia and 24.5 minutes in hypoxia. Under hypoxia, the reported means were 24.0 minutes after 1000 mg Aes-103 and 24.6 minutes after 3000 mg Aes-103. The unadjusted mean differences compared with hypoxia placebo were -0.5 minutes and 0.1 minutes, respectively, with confidence intervals that include zero.

The findings describe measured exercise performance in this study’s conditions and timeframe. They do not establish a general effect on all forms of exercise, people with different characteristics, or performance outside the study setting. The study assessed a time trial after 1 hour following consumption, not long-term adaptation or an illness outcome. Although the registry summary discusses possible relevance to high-altitude adjustment, the primary outcome is exercise time, not prevention of acute mountain sickness.

The confidence intervals indicate substantial uncertainty around the Aes-103 comparison estimates. Their inclusion of zero means the posted unadjusted data are compatible with a range of differences on either side of zero; it does not prove that the conditions are equivalent. The registry does not state an equivalence margin or a clinically meaningful threshold. The p-values are unadjusted, and the original crossover analysis model and multiplicity procedure are not reported.

The normoxia-versus-hypoxia placebo comparison has a mean difference of -2.1 minutes and a confidence interval that does not include zero. This is an observed contrast between the two placebo conditions. It does not by itself establish a mechanism or imply that oxygen setting was the only difference affecting measured performance. All interpretations should remain bounded by the small outcome groups, the posted summaries, and the lack of detail on the original statistical analysis.

16. Why This Trial Matters Statistically

This study illustrates why the design and the analysis must be considered together. The registry describes a randomized crossover study in which participants were assigned to receive four conditions in randomized order with washout periods. Such a design can allow comparisons within participants, but interpretation depends on how repeated observations, sequence, period, and potential carryover are handled. The registry does not report the original model or those analytic details, while the displayed comparisons are unadjusted summaries.

The sample-size illustrations also show how strongly planning requirements depend on the target effect. Planning for a smaller fraction of the observed difference leads to larger participant requirements under the stated assumptions. This is a general feature of statistical power: smaller effects are harder to distinguish from random variation. These planning calculations are not the protocol’s stated sample-size justification, and they should not be confused with the actual enrollment or with evidence about what the study could detect.

Precision is particularly important when interpreting small studies. The Aes-103 mean differences are close to zero in the posted summaries, but their intervals still allow differences in either direction. The point estimates alone do not convey the full uncertainty, and unadjusted p-values do not replace interval estimates or a clearly specified analysis plan.

Finally, safety counts require context. The registry reports few adverse events in the listed groups, but the counts are not enough to establish the absence of risk. Together, these features make the record a useful example of why randomized design, repeated-measures analysis, multiplicity, confidence intervals, and cautious safety interpretation all matter when reading clinical trial results.

17. 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 registry reports total enrollment of 12, while each primary-outcome condition lists 11 participants. It does not explain this difference, state whether the same participants contributed to all four conditions, or describe exclusions or incomplete sequences. The safety denominators also vary by condition. The relationship between enrollment, outcome availability, and adverse-event counting is therefore not clear from the record.

The trial is described as crossover, but the posted comparisons are unadjusted, and the original analysis model is not reported. The record does not specify whether estimates account for within-participant correlation, treatment sequence, period effects, or carryover. The washout duration is recorded as 7 days, but no information is given about how possible carryover was assessed. This limits how directly the summary-based comparisons can be interpreted as the trial’s intended crossover analysis.

The outcome is reported as means and standard errors, without individual measurements or group standard deviations. The registry does not state a threshold for a meaningful difference in exercise time, an equivalence margin, or the trial’s original sample-size justification. The planning illustrations use the observed effect and specified general assumptions; they do not reveal the original design target.

The record does not report the prespecified statistical analysis plan, multiplicity handling, missing-data methods, analysis populations, interim analyses, or the details of masking and random-sequence generation. The unadjusted comparisons therefore have limited context for assessing whether they represent the planned primary analysis. Safety reporting is also limited: one other adverse event is listed in one condition, without its term or relationship to intervention, and death counts are not reported in the registry record.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Evaluation of the Attenuation by Aes-103 of Hypoxia Mediated Decrements in Endurance Exercise Performance — NCT01871142.
• Registry record last updated 2014-10-24; status last verified 2014-10.
• Results first posted 2014-10-24.
• 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.

21. Record Summary

NCT01871142 is a completed randomized, triple-masked crossover study listed in phases 1 and 2 and sponsored by Colorado State University. It enrolled 12 participants. The primary outcome was endurance exercise performance in minutes during a stationary cycle-ergometer time trial, assessed after 1 hour following placebo or Aes-103 under normoxia or hypoxia.

The four conditions were placebo in normoxia, placebo in hypoxia, 1000 mg Aes-103 in hypoxia, and 3000 mg Aes-103 in hypoxia. The registry describes randomized ordering and a 7 day washout period between interventions. Each primary-outcome condition lists 11 participants and a mean with standard error. The posted unadjusted Aes-103 comparisons with placebo under hypoxia have confidence intervals that include zero. The original crossover analysis, multiplicity method, missing-data approach, and sample-size justification are not reported in the registry record.

The safety results list zero serious adverse events in all conditions, zero other adverse events in three conditions, and one in the 3000 mg Aes-103 condition. Death counts are not reported in the registry record.