Aprepitant for PONV Prophylaxis in Outpatient Plastic Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Aprepitant for PONV Prophylaxis in Outpatient Plastic Surgery (NCT00659945), a randomized phase 4 study. The primary outcome is Number of Participants Having Post-operative Emesis and Nausea..

2. Clinical Question

The registry describes the study hypothesis as a comparison of aprepitant plus ondansetron with ondansetron plus placebo for prevention of postoperative emesis in patients at moderate-to-high risk for postoperative nausea and vomiting. The stated aim was to determine the incidence of postoperative nausea and vomiting during the first 48 hours after surgery. The endpoint title refers to participants having postoperative emesis and nausea, while its description also distinguishes the assessment of emesis from analyses of nausea severity. The registry record does not report a more detailed operational definition linking those elements into a single composite outcome.

The clinical question is therefore about the comparison between two prophylactic regimens in this specific surgical setting and risk group. Both groups received ondansetron; the assigned contrast was oral aprepitant versus oral placebo. The posted outcome counts describe participants with the recorded event, not the frequency or duration of individual episodes. They do not by themselves describe the severity of nausea or the experience of every participant during follow-up.

3. Trial Design

This was a phase 4, randomized, double-blind, parallel-group trial sponsored by the University of Pittsburgh. The registry lists the study as completed, with enrollment of 150 participants. The listed study dates are 2008-06 for the start and 2009-11 for primary completion. The registry record does not report the method used to generate the random allocation sequence, how allocation was concealed, or which people were masked.

Participants were assigned to one of two groups. Group A received oral aprepitant plus intravenous ondansetron, and Group B received oral placebo plus intravenous ondansetron. Each group had 75 participants in the posted outcome results. The trial concerned postoperative nausea and vomiting in patients described as being at moderate-to-high risk and undergoing outpatient plastic surgery. The registry record does not report further participant demographics, the plastic surgery procedures included, or detailed inclusion and exclusion criteria.

The primary outcome was assessed at 48 hours after surgery. The registry describes postoperative emesis as present or not present and states that this nominal outcome was analyzed with a chi-square test. It also describes analyses of nausea severity among patients with a verbal rating scale score greater than zero, and comparison of mean verbal rating scale scores over time. The registry lists one outcome measure and one analysis; the record does not clarify how these descriptions of nausea severity relate to the listed primary outcome.

Although the summary describes a planned comparison and the record contains posted results, the registry does not report the original sample-size justification, the detailed statistical analysis plan, or the intended analysis population. It also does not report whether any interim analyses were planned or conducted. Those aspects of the trial design should not be inferred from the completed study status or the observed enrollment.

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: Men and women between 18 and 65 years, at high risk for PONV, undergoing ambulatory plastic surgery under general anesthesia. Exclusion criteria included patient refusal, given other anti-emetics prior to their procedure, history of allergy or sensitivity to study drugs, pregnancy, chronic opioid use, and surgery under intravenous (iv) sedation.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Having Post-operative Emesis and Nausea., measured over 48 hours post surgery.

The primary outcome is titled as the number of participants having postoperative emesis and nausea, with a timeframe of 48 hours after surgery. The posted results give participant counts by group: 7 in Group A, which received oral aprepitant plus intravenous ondansetron, and 22 in Group B, which received oral placebo plus intravenous ondansetron. The registry labels the outcome as a number of participants and describes the event as postoperative emesis and nausea.

The outcome description adds detail about the measurements and analyses. Emesis was recorded as present or not present, making it a binary, or nominal, outcome at the participant level. The description also explains that, among participants with a verbal rating scale score greater than zero, the highest nausea score recorded over the 48 hours was used as a worst nausea score. A Mann–Whitney rank-sum test was used to compare those scores. A multivariate analysis of variance was described for assessing whether mean verbal rating scale scores over time differed between groups.

A participant count is useful because it expresses how many people experienced the recorded event in each group, rather than counting repeated episodes as if they came from different people. However, the registry record does not report an exact rule for classifying the primary outcome when emesis and nausea do not occur together. Nor does it post results for the described nausea-severity analyses. The posted primary counts should therefore be interpreted as the registry’s participant-level event counts, not as a complete description of nausea intensity, timing, or episode burden.

7. Results Posted in the Registry

• Group A(Oral Aprepitant+iv Ondansetron): 9.3% (7/75) versus 29.3% (22/75) on control; risk difference -20.0 percentage points (95% CI -32.2 to -7.8), risk ratio 0.32 (0.14–0.70); unadjusted two-proportion z-test p = 0.002.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary participant-level event: the registry describes emesis as present or not present. For this type of outcome, the basic information is the number of participants with the event and the number assessed in each group. The posted results report 7 of 75 participants in the aprepitant-plus-ondansetron group and 22 of 75 in the placebo-plus-ondansetron group. The registry identifies a chi-squared test for comparing the groups. In general, a chi-squared test assesses whether the observed distribution of participants across outcome categories differs between groups, under assumptions appropriate to the design and data.

A risk difference is an absolute comparison of event proportions between groups. It is calculated by subtracting one group’s event proportion from the other, with the sign depending on the specified direction. The re-calculated risk difference is -0.2 for the comparison as oriented in the posted analysis. A negative value indicates a lower observed event proportion in the aprepitant group. Unlike a relative measure, an absolute difference keeps the comparison on the event-proportion scale. It can therefore be read as the estimated separation in outcome probability between the groups, while recognizing that the estimate has sampling uncertainty.

The re-calculated confidence interval around the risk difference ranges from -0.322 to -0.078. In general, a confidence interval is a range produced by a method that, under repeated use and its assumptions, would cover the underlying quantity at the stated coverage rate at the corresponding frequency. It is not a guarantee that the true value lies in this particular interval, nor does it describe individual participant outcomes. It conveys uncertainty about the estimated group contrast. The posted results list a 95% confidence level for the sponsor’s analysis, but the sponsor’s analysis does not post interval endpoints. The interval accompanying the re-calculation is derived from the posted summary data, not reported as the sponsor’s interval.

The reported sponsor analysis is a chi-squared test with p < 0.05. A p-value describes how unusual results at least as incompatible with a specified null hypothesis would be if that null hypothesis and the analysis assumptions held. It is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of a difference. The re-calculated unadjusted p-value is 0.002, but the record flags a discrepancy between this re-calculation and the sponsor’s own analysis. For that reason, the sponsor’s analysis takes precedence as the trial’s reported inferential result. The registry does not report further details that resolve the difference.

The outcome description also specifies methods for nausea severity. Among participants with a verbal rating scale score greater than zero, the worst score was defined as the highest score recorded over the 48 hours. A Mann–Whitney rank-sum test was used to compare these worst scores. In general, this rank-based method compares the ordering of observations between groups and does not require the same distributional assumptions as a test that directly compares means. The registry does not post results for this analysis, so its estimated group contrast and uncertainty are not available in the registry record.

The description further says that multivariate analysis of variance was used to determine whether mean verbal rating scale scores over time differed between groups. In general, this approach evaluates differences in a set of related outcomes or measurements together. Repeated measurements can be correlated within a participant, and the method’s assumptions and specification matter for interpreting its result. The registry record does not report the model details, the time points included, or results for this analysis. No conclusion about the mean scores over time can therefore be drawn from the posted primary counts.

Over-dispersion is a general concern when variability in outcome data exceeds what a chosen statistical model assumes. If a model underestimates variability, standard errors can be too small and intervals or tests can be misleading. This concept is particularly relevant to some count-data models; the posted primary outcome is described as a participant-level present-or-not-present outcome, and the registry specifies a chi-squared comparison. The record does not report an over-dispersion assessment, and no such assessment should be inferred.

Multiplicity is the issue that arises when several outcomes, time points, or comparisons are tested. Repeated testing can increase the chance of obtaining at least one small p-value by chance if no adjustment or prespecified hierarchy is used. The registry describes multiple ways of examining nausea, but posts only one outcome measure and one analysis, and it does not state whether any multiplicity strategy was planned. The registry record does not report a prespecified hierarchy or adjustment. This is a limitation in interpreting the broader set of analyses described, not a reason to replace the posted primary outcome result with an unreported analysis.

Allocation, masking, and parallel-group features describe different elements of trial design. Random allocation aims to make assigned groups comparable on average with respect to measured and unmeasured factors, while double masking is intended to reduce the influence of knowledge of assignment on care or assessment. A parallel-group design assigns participants to one regimen rather than having the same participant receive both. The registry lists the trial as randomized, double-masked, and parallel, but does not report implementation details such as sequence generation, concealment, or who remained masked. These design labels alone cannot establish how successfully those procedures were carried out.

10. Confidence Intervals and Precision

The re-calculated risk difference is -0.2, with a confidence interval from -0.322 to -0.078. The interval is entirely below zero, which is consistent with a lower observed event proportion in the aprepitant group under the direction used for this calculation. The estimate is not exact: values across the interval represent a range of plausible contrasts under the calculation’s assumptions. The interval should be interpreted as uncertainty about the group-level difference, not as a range containing individual participants’ outcomes.

Precision concerns how narrowly the data locate an effect estimate. A narrower interval generally indicates more precise estimation, while a wider interval indicates greater uncertainty. The available interval provides information beyond a p-value because it conveys the scale and direction of estimates compatible with the data. The sponsor’s own reported result gives p < 0.05 but does not report an effect estimate or confidence-interval endpoints. The interval belongs to the unadjusted re-calculation from the posted counts; it is not reported as the sponsor’s interval.

The trial enrolled 150 participants, with 75 in each group in the posted results. The registry does not report an original precision target or sample-size justification, so the observed enrollment cannot be judged against an intended target using the registry record alone. The record also does not report participant-level data, details of missing outcomes, or the number included in each of the described nausea-severity analyses. Those omissions limit assessment of how the primary interval would relate to other outcome definitions or analyses.

Statistical precision is distinct from clinical importance. The confidence interval describes uncertainty in the estimated numerical contrast, but the registry does not state a threshold for a difference considered important. The interval also cannot account for design or analysis details that are absent from the record. It is best read alongside the posted counts and the sponsor’s reported analysis, with the discrepancy noted rather than treating the re-calculated interval as the official sponsor result.

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 estimates are expressed as participants per arm for this binary outcome. They are not total event counts. The estimates illustrate how many participants might be needed in each group under specified planning assumptions, using the observed effect as a starting point. They are not the trial’s reported enrollment plan, and the registry record does not report the original sample-size justification or the assumptions used when designing the trial.

The planning illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It uses an effect to detect set at the stated fraction of the observed effect. The estimates are listed for planning for 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. The corresponding columns describe participants per arm for 80% power and participants per arm for 90% power. In plain terms, power is the probability that a study using the specified design would detect an effect of the assumed size at the stated significance level, if that effect and the planning assumptions were correct.

For a given effect assumption, the 90% power column requires more participants per arm than the 80% power column. The estimates also increase when planning for smaller fractions of the observed effect: a smaller effect is harder to distinguish from random variation, so more participants are needed under these assumptions. The 75% and 50% rows are planning illustrations for effects smaller than the observed estimate, not claims that those effects were observed.

These figures are planning illustrations, not observed power. They do not describe the probability that the completed trial’s result is correct, and they do not substitute for the trial’s original design calculations. The record’s stated planning assumptions are known for this illustration; the trial’s own original design assumptions are not reported in the registry record.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.293; treatment proportion p₁ = 0.093; average p̄ = 0.193.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5585 = 1.0946.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5403 = 0.4547.
4. n = (1.0946 + 0.4547)² / (-0.2000)² = 60.0, rounded up to 61 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
p0 <- 0.293333333333333                          # control proportion
p1 <- 0.0933333333333333                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(659945)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 61 (80% power), 80 (90% power)
 75% of observed effect: n per arm = 118 (80% power), 158 (90% power)
 50% of observed effect: n per arm = 288 (80% power), 385 (90% power)
power.prop.test: 60 
Simulated power at n = 61 per arm: 0.820 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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. Analyses Reported by the Sponsor

The registry reports that the sponsor analyzed the primary comparison with a chi-squared test and gives p < 0.05. It does not provide a sponsor-reported effect estimate or confidence-interval endpoints for that analysis. The posted group counts are 7 of 75 participants in Group A and 22 of 75 in Group B.

A simple unadjusted re-calculation from those counts gives a risk difference of -0.2, with a confidence interval from -0.322 to -0.078, and an unadjusted p-value of 0.002. The record flags a discrepancy between the sponsor’s reported result and this re-calculation. Because that discrepancy is recorded, the sponsor’s own analysis takes precedence when stating the trial’s reported inferential finding. The re-calculation can still help describe the direction and estimated size of the contrast implied by the posted counts, but it must not be presented as the sponsor’s original analysis.

The registry record does not report sufficient detail to explain the discrepancy. It does not establish whether the sponsor used a different analysis population, data handling rule, or statistical specification. Those possibilities should not be assumed. The appropriate reading is to keep the reported sponsor result distinct from the simple re-calculation and to acknowledge that the record does not resolve why they differ.

14. Multiplicity, Missing Data and Analysis Populations

The registry describes more than one approach to assessing nausea: a participant-level event outcome, a worst nausea score among participants with a verbal rating scale score greater than zero, and a comparison of mean verbal rating scale scores over time. However, the record lists one outcome measure and one analysis, and it posts no secondary outcomes. Results for the described nausea-severity analyses are not reported in the registry record.

When several outcomes or analyses are considered, multiplicity can affect interpretation. In general, testing many hypotheses can increase the chance that at least one result appears statistically notable by chance. Researchers may address this through a prespecified hierarchy, adjustment, or other strategy. The registry record does not report whether any multiplicity adjustment or hierarchy was planned. It is therefore not possible to determine from this record how the several descriptions of nausea assessment were handled in the trial’s full analysis plan.

The registry record also does not report how missing outcome data were handled, whether any participants withdrew or were excluded from the primary analysis, or the analysis population used by the sponsor. The posted group counts give 75 participants in each arm, but those counts alone do not establish whether every randomized participant contributed a complete outcome or how any unavailable assessment was treated. No assumptions about missing data should be made from the equality of the group sizes.

The record does not report an intention-to-treat definition, a per-protocol analysis, or sensitivity analyses for missing outcomes. It also does not report whether participants were analyzed according to assigned group or according to treatment received. These details matter because choices about population and missing data can affect the estimated contrast and its uncertainty. Without them, the sponsor’s reported chi-squared result and the posted counts can be described, but a fuller assessment of the analysis population and robustness is not possible.

These omissions do not establish that multiplicity or missing-data problems occurred. They mean only that the registry record does not document the relevant plans and procedures. Interpretations should distinguish what is posted—the primary group counts and sponsor’s p-value—from analyses or safeguards that are not described.

15. 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 1% reporting threshold.

The registry lists serious adverse events affecting 0 participants in Group A and 0 participants in Group B. Each group had 75 participants at risk in the serious adverse event listing. It also lists other, non-serious adverse events affecting 0 participants in each group, with 75 participants at risk in each group for that listing.

These figures describe the adverse-event entries posted in the registry record. They should be read as counts for the listed categories and participant groups, not as proof that no symptoms or events of any kind occurred during the study. The registry does not provide serious adverse event terms, and no serious-event terms are listed. Death counts are not reported in the registry record.

Zero listed events in these categories do not establish that the regimens have no risks. The figures do not characterize event timing, duration, severity below the serious threshold, or causal attribution. Nor do they resolve how adverse events were collected or whether all participants had complete safety follow-up. Those details are not reported in the registry record. The appropriate statistical reading is limited to the posted counts and denominators.

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

The registry results show that 7 participants in the aprepitant-plus-ondansetron group and 22 participants in the placebo-plus-ondansetron group were counted for the primary postoperative outcome at 48 hours. Each group had 75 participants in the posted results. The simple unadjusted re-calculation estimates a risk difference of -0.2, with a confidence interval from -0.322 to -0.078. The sponsor’s reported chi-squared analysis gives p < 0.05. The record flags a discrepancy between the sponsor analysis and the re-calculation, so the sponsor’s own result takes precedence as the trial’s reported inferential finding.

These results describe the observed group comparison in this completed, randomized, double-blind, parallel-group phase 4 trial of patients at moderate-to-high risk undergoing outpatient plastic surgery. They do not show the outcomes of every possible patient or establish what would happen in a different surgical setting, risk group, or care context. The registry record does not report enough participant characteristics or procedural detail to assess how closely the enrolled participants resemble other populations.

The primary counts do not explain the mechanism of any observed difference, measure nausea severity, or describe the number and duration of episodes. Although the outcome text describes analyses of worst nausea scores and mean verbal rating scale scores over time, their results are not reported in the registry record. No secondary outcomes are posted.

Statistical evidence and clinical importance are separate questions. The p-value does not measure the size or importance of the difference, and the confidence interval does not specify what difference would matter to patients or clinicians. The registry does not report a threshold for clinical importance. The record also does not report the original sample-size justification, missing-data procedures, or analysis-population definition. These absences limit how fully the reported findings can be evaluated.

Accordingly, the posted data support a description of the observed counts and the analyses reported in the registry, not a treatment recommendation. The available information does not justify extending the result beyond this trial’s comparison and setting or making claims about outcomes that were not posted.

17. Why This Trial Matters Statistically

This trial is statistically informative because it compares two regimens that share ondansetron and differ in the addition of oral aprepitant versus oral placebo. The randomized, double-blind, parallel-group design is intended to support a fair group comparison, while the binary participant-level primary outcome permits a direct description of how many participants experienced the recorded event. The registry lists 75 participants in each group and posts the counts for the 48-hour outcome.

The analysis also illustrates why a test result should not stand alone. The sponsor reported a chi-squared analysis with p < 0.05, while the unadjusted re-calculation from the posted counts gives a risk difference of -0.2 and p-value of 0.002. The record flags a discrepancy, so the sponsor’s analysis takes precedence. Presenting the estimate and interval from the simple re-calculation separately makes clear both the scale of the contrast implied by the counts and the distinction between that calculation and the official reported analysis.

There is also a useful distinction between outcome incidence and symptom severity. The main posted counts concern participants with the recorded event, while the outcome description identifies separate methods for worst nausea scores and scores over time. Because those results are not posted, the participant counts cannot stand in for severity outcomes. This makes clear why precise endpoint definitions and complete results matter when a trial describes several related measurements.

Finally, the sample-size illustrations show how planning depends on the effect size selected and desired power, while the original design justification is not reported. That separation prevents retrospective planning calculations from being mistaken for the trial’s actual design rationale. Taken together, the record offers a basis for understanding a specific randomized comparison while also showing the limits imposed by incomplete analysis and design reporting.

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.

The registry record leaves several trial-specific details unavailable. It does not report the randomization sequence method, allocation concealment procedures, or who was masked. Although the study is labeled randomized and double-blind, those labels do not reveal how the procedures were implemented. The record also lacks detailed eligibility criteria, participant characteristics, and the range of plastic surgery procedures represented, which limits assessment of how broadly the results apply.

The primary endpoint description refers to postoperative emesis and nausea but does not fully specify how a participant was classified for the participant-level count when the symptoms did not occur together. The text gives details about emesis recording and separate nausea severity analyses, but does not post results for those severity analyses. This leaves uncertainty about the relationship between the endpoint title, the count reported, and the additional assessments.

The sponsor’s analysis is reported only as a chi-squared test with p < 0.05. The registry does not provide its effect estimate or interval, and the record flags a discrepancy with the unadjusted re-calculation from the counts. Details sufficient to explain that discrepancy are not reported. The original sample-size justification, detailed analysis plan, analysis population, missing-data handling, and any interim analyses are also not reported in the registry record.

Safety reporting is limited to zero serious and zero other adverse events affecting participants in the listed groups. The record does not give event terms, death counts, collection methods, or additional follow-up detail. These limitations do not show that an unreported procedure or event occurred; they identify information that cannot be assessed from the registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Aprepitant for PONV Prophylaxis in Outpatient Plastic Surgery — NCT00659945.
• Registry record last updated 2013-02-06; status last verified 2013-02.
• Results first posted 2011-12-07.
• 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

NCT00659945 is a completed phase 4 randomized, double-blind, parallel-group trial sponsored by the University of Pittsburgh. It enrolled 150 participants with moderate-to-high risk of postoperative nausea and vomiting undergoing outpatient plastic surgery. The listed start and primary completion dates are 2008-06 and 2009-11.

The comparison was oral aprepitant plus intravenous ondansetron versus oral placebo plus intravenous ondansetron. At 48 hours after surgery, the posted primary outcome counts were 7 of 75 participants in the aprepitant group and 22 of 75 in the placebo group. The sponsor reported a chi-squared analysis with p < 0.05; the registry flags a discrepancy with the unadjusted re-calculation, so the sponsor’s analysis takes precedence. Results for the described nausea-severity analyses are not reported in the registry record.

The adverse-event listing records 0 participants affected by serious events and 0 affected by other events in each group. The registry does not report the original sample-size justification, detailed missing-data procedures, or the full analysis population.