Immersive Virtual Reality Exposure for Reducing Preoperative Anxiety in Children: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Immersive Virtual Reality Exposure for Reducing Preoperative Anxiety in Children (NCT07018999), a randomized na study. The primary outcome is Modified Yale Preoperative Anxiety Scale (mYPAS) (T1).

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with triple masking recorded in the registry. One group received an immersive virtual reality operating-theatre tour in addition to usual interventions, while the control group received usual care and perioperative information. The registry lists the intervention as a device. The recorded enrollment was 114, and the trial status is completed. The registry lists phase as not applicable.

The trial was sponsored by Hong Kong Children's Hospital. The recorded start date is 2022-11-17 and the primary completion date is 2024-09-11. The posted primary outcome summaries include 34 participants in the VR group and 38 in the control group. These outcome-specific counts are distinct from the registry's overall enrollment figure; an explanation for the difference is not reported in the registry record. The adverse-event summaries use 42 participants at risk in each group, and the reason those denominators differ from the primary outcome counts is not reported in the registry record.

The primary outcome was mYPAS during anaesthesia induction, from entry to the operating theatre until successful induction, with the registry giving a usual timeframe of about 10 to 15 minutes. The registry also lists secondary outcomes concerning baseline anxiety, induction compliance, procedure behaviour, parental anxiety and parental satisfaction. Numerical results are posted for three secondary outcomes: baseline mYPAS, the Induction Compliance Checklist and the Procedure Behaviour Rating Scale. Numerical results for the other listed secondary outcomes are not reported in the registry record. The original sample-size justification, full protocol, eligibility criteria, and detailed description of masking procedures 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.

Before assignment: After patient enrollment, 30 of them dropped out before randomization due to surgery cancellation (n=10) , change of surgical plan (n=12), advancement or delay of surgery date resulting in children either too young or too mature for inclusion (n=4), or unavailability of researchers on surgery date (n=4).

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 Modified Yale Preoperative Anxiety Scale (mYPAS) (T1), measured over During anaesthesia induction, from entering the operating theatre to successful anaesthesia induction (entered into state of general anaesthesia), usual time frame about 10 to 15 minutes..

The primary endpoint was the Modified Yale Preoperative Anxiety Scale (mYPAS) score during anaesthesia induction. The registry describes assessment from entering the operating theatre to successful induction, when the child enters a state of general anaesthesia. Its usual timeframe is described as about 10 to 15 minutes. The scale is intended to quantify observable preoperative anxiety in children. It has 27 items across five domains: activity, emotional expressivity, state of arousal, vocalization, and use of parents or legal guardians. Scores range from 23.3 to 100, with higher scores indicating greater preoperative anxiety. The registry states that a score of >= 30 indicates a high anxiety level.

The registry calls mYPAS a gold-standard instrument for assessing preoperative anxiety and states that a blinded researcher or anaesthesiologist would assess it. Using a continuous score preserves information about the measured level of anxiety rather than reducing every result to a high-versus-not-high classification. The primary question is a comparison between groups at induction, not a comparison of the proportion above the stated cutoff. The registry's stated definition of the primary outcome refers to a 20% change between groups. The posted summaries report group means and standard deviations, but the registry record does not report how that criterion was incorporated into the trial's own statistical analysis.

7. Results Posted in the Registry

• Virtual reality (VR) group: mean 31.40 versus 37.30 on control; difference -5.90 (95% CI -11.27 to -0.53), standardized effect d = -0.49; z-test p = 0.031.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Baseline Preoperative Anxiety Score Using mYPAS on Admission (T0)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Virtual reality (VR) group: mean 34.80 versus 36.30 on control; difference -1.50 (95% CI -8.57 to 5.57), standardized effect d = -0.10; z-test p = 0.677.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Virtual reality (VR) group and the control. The interval gives the range of effects that remain compatible with the data.

Induction Compliance Checklist

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Virtual reality (VR) group: mean 0.82 versus 1.13 on control; difference -0.31 (95% CI -0.91 to 0.30), standardized effect d = -0.23; z-test p = 0.319.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Virtual reality (VR) group and the control. The interval gives the range of effects that remain compatible with the data.

Procedure Behaviour Rating Scale PBRS

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Virtual reality (VR) group: mean 1.56 versus 1.92 on control; difference -0.36 (95% CI -1.25 to 0.53), standardized effect d = -0.19; z-test p = 0.427.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Virtual reality (VR) group and the control. The interval gives the range of effects that remain compatible with the data.

The three secondary outcomes with posted numerical summaries show a broadly similar direction in their group means: the VR group means are lower than the control group means. However, their recalculated confidence intervals include zero, and their unadjusted p-values do not indicate clear evidence of a difference under the simple comparisons used. Taken together, the secondary outcomes do not provide a uniformly precise or independently decisive pattern. They are best read as additional descriptive context for the primary comparison rather than as a separate confirmation of it.

Baseline mYPAS is measured before the intervention exposure described for the day of surgery, while the compliance and behaviour measures relate to induction. Their roles differ: baseline anxiety describes scores at ward admission, and the induction measures describe aspects of behaviour during the perioperative process. The registry also names parental anxiety and satisfaction outcomes, but numerical results for those outcomes are not reported in the registry record. The available secondary outcomes therefore give only a partial view of the broader outcomes listed.

Unadjusted secondary comparisons carry less weight when several outcomes are considered because repeated testing can increase the chance of seeing an apparently notable result by chance. General statistical explanation: multiplicity refers to the increased interpretive uncertainty that comes from examining many outcomes or comparisons, particularly when no adjustment or hierarchy is specified. The registry record does not report a multiplicity strategy, a hierarchy for secondary outcomes, or trial-reported analyses. Consequently, the secondary results should not be treated as confirmatory claims or as proof that the primary result is replicated across different measures. Their value is chiefly descriptive, and any interpretation should take account of both the limited precision and the incomplete reporting of the full set of listed outcomes.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Baseline Preoperative Anxiety Score Using mYPAS on Admission (T0)
• Induction Compliance Checklist
• Procedure Behaviour Rating Scale PBRS
• Parental Anxiety by State-trait Anxiety Inventory (STAI)-T
• Parental Anxiety by State-trait Anxiety Inventory (STAI-S)
• Parental Satisfactory Score

9. Statistical Interpretation

10. Statistical Methods Explained

What the outcome summaries describe

The primary endpoint is a continuous score, and the registry posts each group's mean and standard deviation. A mean describes the group's average score; a standard deviation describes the spread of individual scores around that average. These are complementary summaries. A difference in means describes the contrast between group averages, while the standard deviations indicate how much participants' scores vary within each group. The mean difference is expressed as VR minus control, so a negative value corresponds to a lower mean score in the VR group.

General statistical explanation: an unadjusted comparison uses the group summaries without accounting for other variables. A recalculated estimate can be useful for understanding the posted results, but it is not a substitute for the trial's own prespecified analysis. The registry lists no reported analyses, so there is no registry-reported adjusted model, test procedure, or analysis population to compare against the simple recalculation.

How to read the uncertainty interval

The confidence interval around a mean difference describes a range of values compatible with the observed data under the assumptions of the method used. It communicates both the direction and the precision of the estimate. If the interval is relatively narrow, the estimate is more precise; if it is wide, many different values remain compatible with the data. An interval crossing zero would include no mean difference, whereas an interval entirely on one side of zero would indicate a direction for the estimated contrast under the calculation used. These are general interpretations of confidence intervals, not statements about a specific clinical threshold.

For the primary outcome, the recalculated mean difference is -5.9, with a 95% confidence interval from -11.27 to -0.529. The interval is entirely negative. The unadjusted p-value is 0.031. A p-value is a measure of how unusual data at least as incompatible with a no-difference model would be under the assumptions of the test; it is not the probability that the null hypothesis is true, nor a measure of clinical importance. The registry does not report a trial-authored test, so the p-value should be understood as part of the recalculated unadjusted comparison.

Why group variability matters

General statistical explanation: when outcomes vary substantially among participants, a group mean is less precisely estimated than it would be with less variability, all else being equal. The primary outcome standard deviations are 8.2 in the VR group and 14.5 in the control group. The outcome counts are 34 and 38, respectively. These group-level summaries help explain why the estimate has uncertainty. They do not show the distribution's shape, whether there were extreme scores, or whether any modeling assumptions were checked; those details are not reported in the registry record.

The recalculated comparison also reports a standardized effect estimate of -0.494, using a pooled standard deviation of 11.95. Standardization expresses the mean difference relative to a pooled measure of within-group spread, so it can help describe the size of a contrast on a scale independent of the original score units. It does not make the result inherently clinically important, and it does not replace interpretation on the mYPAS scale. The calculation is unadjusted and should be interpreted alongside the raw score difference and its interval.

What the record leaves uncertain

The registry record does not report the original statistical analysis plan, the sample-size justification, the method used for handling missing outcomes, or whether participants were analyzed according to randomized assignment. It also does not report whether any covariates were included in the trial's primary analysis, how the stated 20% change was assessed, or whether interim analyses were planned or performed. These omissions limit assessment of alignment between the posted summary comparison and the trial's intended analysis.

General statistical explanation: randomization supports a fair comparison by assigning participants to groups by chance, but the interpretation of a randomized trial still depends on follow-up, outcome availability, adherence, and analysis choices. The registry record gives a randomized design, but the outcome summaries alone cannot answer all those questions. A straightforward recalculation from means, standard deviations, and group counts can describe the observed contrast and its approximate precision. It cannot recover unreported decisions about the trial's conduct or replace an analysis based on individual participant data.

11. Confidence Intervals and Precision

The primary mean difference is -5.9 mYPAS points, with a recalculated 95% confidence interval from -11.27 to -0.529. The interval is entirely below zero, indicating that the recalculated estimate is in the direction of a lower group mean in the VR arm. Its width also matters: the results remain compatible with a range of mean differences, from a relatively larger negative contrast to one close to zero. The registry record does not identify a minimum clinically important difference, so the interval cannot be classified against a registry-reported clinical threshold.

Precision depends on the amount of information in the comparison, including the number of observed outcomes and variability in scores. The posted primary summaries include 34 participants in the VR group and 38 in the control group, with standard deviations of 8.2 and 14.5. The unequal outcome counts and differing spreads are part of the context for the interval. The registry's overall enrollment is 114, but a reason for the difference between overall enrollment and the primary outcome counts is not reported in the registry record. The registry also does not report missing-data methods or a participant flow account, so the potential effect of unavailable outcomes cannot be assessed.

The interval and p-value are recalculated from posted summary statistics and are unadjusted. They should not be read as a trial-reported confidence interval or as evidence that all possible sources of uncertainty have been addressed. The registry record does not report a prespecified analysis, model diagnostics, adjustment for other variables, or a protocol-defined interpretation threshold. In particular, statistical precision and clinical importance are distinct: a confidence interval describes uncertainty about the estimated mean contrast, while clinical meaning requires context that is not reported in the registry record.

12. 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 describe hypothetical future study sizes based on the observed primary outcome effect, not the number enrolled in this completed trial. They are participants per arm, not total events. The planning calculation assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers effects equal to 100%, 75%, and 50% of the observed effect. The original trial's own sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the planned number of participants per arm for a study designed to have an 80% chance of detecting the specified effect under the stated assumptions, if that effect is present. The 90% power column gives the corresponding number per arm for a higher planned chance of detection. These are planning targets, not guarantees about a future study's result. The figures are 65 and 87 participants per arm for planning at 100% of the observed effect; 115 and 154 for 75% of the observed effect; and 258 and 345 for 50% of the observed effect, for 80% and 90% power respectively.

Smaller effects are harder to distinguish from random variation, so planning to detect a smaller fraction of the observed effect requires more participants per arm. The planning figures are illustrations based on an effect estimated from this trial's posted summaries. They are not observed power, and they do not establish what sample size the trial originally intended or whether its enrollment was adequate for its prespecified objective.

13. 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 = -5.900; pooled standard deviation σ = 11.951.
2. n = 2 × (1.96 + 0.842)² × 11.951² / -5.900² = 64.4, rounded up to 65 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 <- -5.9                      # observed difference in means
sigma <- 11.9511924091281                     # 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(7018999)
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 = 65 (80% power), 87 (90% power)
 75% of observed effect: n per arm = 115 (80% power), 154 (90% power)
 50% of observed effect: n per arm = 258 (80% power), 345 (90% power)
power.t.test: 65.4 
Simulated power at n = 65 per arm: 0.801 (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.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and multiple secondary outcomes, including baseline anxiety, induction compliance, procedure behaviour, parental anxiety, and parental satisfaction. The record states that seven outcome measures were registered and names six secondary outcomes, but numerical summaries are posted for only three secondary outcomes. Results for the other named outcomes are not reported in the registry record. No analyses are listed as reported analyses.

When a study examines several outcomes, the chance of finding at least one apparently noteworthy result can rise if each comparison is interpreted separately without a prespecified strategy. General statistical explanation: a multiplicity plan may identify a primary outcome, define an order for testing outcomes, or adjust interpretation to account for multiple comparisons. The registry record does not report such a plan, nor does it describe a hierarchy among the secondary outcomes. The reported secondary p-values are unadjusted recalculations, and should not be read as accounting for the full set of outcomes.

The registry record does not report missing-data methods, the number of participants with missing results for each outcome, imputation procedures, or sensitivity analyses. It also does not state whether the analyses followed an intention-to-treat approach or another analysis population. The difference between the overall enrollment of 114 and the primary outcome counts is not explained in the registry record. Without participant flow and outcome availability details, it is not possible to determine from the posted summaries whether the analysis groups fully reflect randomized assignment or how missing outcomes may have affected the estimates.

The record also does not report an interim-analysis plan, stopping rules, or the original statistical analysis plan. These omissions do not establish that such procedures were absent; they mean only that they are not reported in the registry record. Accordingly, the primary recalculation can be described as an unadjusted summary-statistic comparison, but its relationship to any prespecified trial analysis cannot be established from the registry information.

15. 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 adverse-event summaries list 42 participants at risk in each group. In both groups, the registry reports zero serious adverse events, zero other adverse events, and zero deaths. These figures describe what was recorded in the registry for the stated denominators; they do not mean that the event risk is known to be zero in all participants or that no events could have gone unrecorded.

The adverse-event denominators differ from the primary outcome counts, which are 34 in the VR group and 38 in the control group. The registry record does not explain this difference or give further detail on adverse-event ascertainment, definitions, monitoring, or reporting periods. No serious adverse-event terms are listed. The zero counts should therefore be interpreted as the posted registry summaries, with caution about the limited information on how safety events were collected and how the denominators were determined. These summaries do not establish the absence of risk.

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

The posted primary summaries show lower mean mYPAS during induction in the VR group than in the control group. The recalculated unadjusted mean difference is -5.9, and its 95% confidence interval is -11.27 to -0.529. This conveys the direction and estimated precision of the group contrast in the available summaries. It does not, on its own, establish the clinical importance of the difference. The registry does not report a threshold for a clinically meaningful change, and the stated 20% criterion cannot be evaluated from the summaries alone without knowing how the trial applied it.

The comparison concerns the measured score at induction. It is not a direct measure of every aspect of perioperative anxiety, later experience, or longer-term outcome. The registry lists additional outcomes, but numerical results are posted for only three secondary measures. The other named secondary outcomes are not reported in the registry record. The primary comparison therefore should not be generalized to unreported outcomes or interpreted as a comprehensive assessment of all effects relevant to children and families.

The randomized design is relevant to interpreting a group comparison, but the available registry information does not describe the full conduct of the analysis. Outcome counts are lower than overall enrollment, and the reason is not reported in the registry record. Missing-data handling, the analysis population, and an investigator-reported primary analysis are also not reported. As a result, the recalculated comparison should be treated as a transparent description of the posted means and variability, not as a replacement for a complete trial report.

Finally, a difference in group averages does not imply that every participant in one group had a lower score than every participant in the other group. Individual scores vary, as reflected in the standard deviations. The estimate applies to the participants represented by the reported summaries; how well it applies elsewhere cannot be determined from the registry record. These results describe an observed contrast and its uncertainty, not a recommendation about care.

17. Why This Trial Matters Statistically

This trial addresses a statistical problem common to clinical research: how to compare a continuous, observed behaviour score between randomized groups when the outcome varies across participants and the available results are brief summary statistics. The primary result illustrates why an estimate, an uncertainty interval, and the underlying group means are more informative together than a single p-value. The direction of the mean contrast is visible, while the interval communicates the range of values still compatible with the recalculation.

The registry also makes clear that design features and result interpretation are separate questions. Randomization and recorded triple masking are important design descriptions, but they do not answer how missing outcomes were handled, whether the analysis followed randomized assignment, or how the stated 20% change was evaluated. Those details are not reported in the registry record. A careful reading distinguishes what the record documents from what cannot be established from its posted summaries.

The planning illustrations are another useful statistical lesson. They show how the number of participants per arm changes when a study is designed to detect a smaller fraction of an observed effect or to have a higher planned probability of detection. Those calculations are not evidence about the power achieved by this completed trial, and they do not reconstruct its original design assumptions. The distinction between prospective planning and retrospective interpretation helps prevent a common misreading of power calculations.

Finally, the difference between overall enrollment, primary outcome counts, and adverse-event denominators highlights the importance of reporting participant flow and outcome availability. The record does not explain these differing counts. That gap limits assessment of precision and potential missing-data effects, even when the posted group summaries allow a straightforward comparison. The statistical value of the record lies both in the estimate it reports and in making clear which analytic details remain unavailable.

18. 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 limitations of interpretation arise from the registry record. The primary outcome summaries include 34 participants in the VR group and 38 in the control group, while overall enrollment is 114. Adverse-event summaries use 42 participants at risk per group. The reasons for these different counts are not reported in the registry record, and participant flow and outcome availability by group are not described. This makes it difficult to assess how the posted summaries relate to all randomized participants.

The registry does not report the original sample-size justification, statistical analysis plan, missing-data methods, or analysis population. It also does not report an investigator-authored analysis or explain how the stated 20% change criterion was evaluated. The recalculated comparisons are unadjusted, and the registry does not state whether a different primary analysis was conducted. The displayed estimates therefore cannot be assumed to reproduce the trial's intended analysis.

Only three secondary outcomes have numerical summaries, despite additional outcomes being named in the registry. The missing secondary results limit assessment of the complete set of planned measures. No multiplicity strategy is reported, so the unadjusted secondary comparisons should be viewed cautiously. The record also gives little detail on the implementation of usual care, the VR exposure beyond its general description, eligibility criteria, adherence, or masking procedures. These details are not reported in the registry record.

The safety summaries report zero events in the listed categories, but event definitions, monitoring, and ascertainment details are not reported. The registry record is therefore insufficient to make broad conclusions about safety or the generalizability of the outcome comparison. These limitations concern reporting and interpretation; they do not establish that the trial lacked procedures that are simply not described in the record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Immersive Virtual Reality Exposure for Reducing Preoperative Anxiety in Children — NCT07018999.
• Registry record last updated 2025-10-23; status last verified 2025-09.
• Results first posted 2025-10-23.
• 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.

22. Record Summary

NCT07018999 is a completed randomized, parallel-group trial sponsored by Hong Kong Children's Hospital. The registry records triple masking and enrollment of 114. The intervention was an immersive virtual reality operating-theatre tour added to usual care; the comparator was usual care and perioperative information. The primary outcome was mYPAS during anaesthesia induction.

The posted primary summaries show means of 31.4 for the VR group and 37.3 for the control group, based on 34 and 38 participants. The recalculated unadjusted mean difference is -5.9, with a 95% confidence interval from -11.27 to -0.529 and an unadjusted p-value of 0.031. The registry lists no reported analyses. Numerical results are available for three secondary outcomes. Adverse-event summaries report zero serious events, zero other events, and zero deaths in both groups, with 42 at risk per group. The original analysis plan, missing-data methods, sample-size justification, and explanation for the differing participant counts are not reported in the registry record.