This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for RCT (Randomized Controlled Trial) of IV Acetaminophen for Post Operative Vaginal Reconstruction Pain (NCT02043704), a randomized phase 4 study. The primary outcome is Pain While Active - 18 hr.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02043704 |
| Phase | Phase 4 |
| Condition | Post Operative Pain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 100 |
| Arms in the primary outcome | 2 |
| Lead sponsor | TriHealth Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing vaginal reconstructive surgery. The trial enrolled 100 participants; the primary endpoint results are recorded for 47 participants in the IV acetaminophen arm and 43 in the saline arm. The registry record does not report further eligibility details or the characteristics of the enrolled participants.
Intervention
IV acetaminophen: 1000mg in 100mL solution every 6 hours for 24 hours, with the first dose before anesthesia induction, approximately 30 minutes before skin incision. The arm description specifies a total of 4 doses. Participants could also receive IV narcotic as needed for additional pain relief.
Comparator
IV saline, given in 100mL doses every 6 hours for 24 hours. The first dose was before anesthesia induction, approximately 30 minutes before skin incision, and the arm description specifies a total of 4 doses. Participants could also receive IV narcotic as needed.
Primary question
The primary endpoint asks how pain while active differs between the assigned groups 18 hours after surgery. Participants reported pain on a 0-100 mm visual analog scale, anchored at no pain and the worst pain imaginable. The registry record also describes narcotic consumption and pain scores as trial interests, but the posted primary outcome is the active-pain score at 18 hours.
3. Trial Design
This was a Phase 4, randomized, triple-masked, parallel-group trial sponsored by TriHealth Inc. The registry record lists an enrollment of 100 participants. The trial began in 2014-01, reached primary completion in 2016-08, and is marked completed. Further details about who was masked, the randomization procedure, and the allocation ratio are not reported in the registry record.
Participants were assigned to IV acetaminophen or saline. The acetaminophen arm received 1000mg in 100mL every 6 hours for 24 hours; the first dose was scheduled before anesthesia induction, approximately 30 minutes before skin incision. The saline arm received matching 100mL infusions on the same schedule. Each arm description states that a total of 4 doses were planned. All participants could receive IV narcotic as needed for additional pain relief.
The primary endpoint was pain while active at 18 hours after surgery. Pain was self-reported on a visual analog scale, and the posted results give medians and interquartile ranges by arm. The registry record describes additional measures, including pain at other time points, narcotic consumption, narcotic-associated side effects, and time to first rescue narcotic. The complete protocol and the detailed measurement schedule for each secondary outcome are not reported in the registry record.
The primary endpoint data are recorded for 47 participants assigned to IV acetaminophen and 43 assigned to saline. The registry record does not explain the difference between the enrollment figure and the numbers with primary outcome data, or state how missing outcome data were handled.
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
| Stage | IV Acetaminophen | Saline |
|---|---|---|
| STARTED | 50 | 50 |
| COMPLETED | 47 | 43 |
| NOT COMPLETED | 3 | 7 |
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.
| Characteristic | Unit | IV Acetaminophen | Saline | Total |
|---|---|---|---|---|
| Participants analysed | 47 | 43 | 90 | |
| Age, Continuous | years | 57.3 (SD 12.8) | 59.4 (SD 11.4) | 58.3 (SD 12.12) |
| Sex: Female, Male: Female | Participants | 47 | 43 | 90 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 47 | 43 | 90 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 47 | 43 | 90 |
6. Primary Endpoint
The registry lists the primary outcome as Pain While Active - 18 hr, measured over 18 hours.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | mm |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is pain while active, self-reported 18 hours after surgery on a 0-100 mm visual analog scale. The scale anchors are 0 for no pain and 100 for the worst pain imaginable. A higher score therefore represents greater reported pain. The endpoint focuses on pain during activity rather than pain at rest, as specified in the outcome description.
The results are reported as a median and interquartile range for each arm. As a general statistical rationale, the median describes the middle of a distribution and is less affected by extreme observations than the mean. The interquartile range describes the middle half of observed values, giving a sense of their spread. Reporting both helps readers understand the typical recorded score and the variability in scores without assuming that the distribution is symmetric.
A patient-reported scale can capture an experience that is not directly measured by an instrument or laboratory test. Its interpretation depends on the scale anchors and the time and context of assessment. In this trial, the primary assessment is at 18 hours after surgery and concerns pain while active. The registry record does not report a minimally important difference, an equivalence margin, or a primary endpoint confidence interval, so the clinical importance and precision of a between-arm difference cannot be judged from those quantities.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
At 18 hours, the median pain score while active was 42.0 mm in the IV acetaminophen arm, with an interquartile range from 27.5 to 61.0. In the saline arm, the median was 50.0 mm, with an interquartile range from 28.5 to 71.5. These are descriptive summaries of the participants whose results are recorded for each arm. They do not, by themselves, establish the size or precision of a treatment contrast.
The registry reports a Wilcoxon (Mann-Whitney) comparison with p = 0.328. This is the posted inferential result for the primary endpoint. In general, a p-value measures how compatible the observed data are with a specified null model under the assumptions of the test. It is not the probability that the null hypothesis is true, and it does not quantify the probability that the observed difference arose by chance. The registry does not report a primary between-arm effect estimate or confidence interval, so the magnitude and precision of the contrast are not directly summarized by those measures.
The result is described as an equivalence analysis in the registry, but no equivalence margin or confidence interval is reported. A nonsignificant test alone does not establish equivalence: an equivalence conclusion requires a prespecified acceptable range for differences and evidence that the uncertainty interval lies within that range. Because those details are not reported in the registry record, the p-value should be read as the result of the stated Wilcoxon comparison, not as proof that the groups had equivalent pain scores.
The ranges of observed scores are broad in both arms. As a general point, overlapping interquartile ranges do not determine whether a statistical test is significant, and separated ranges would not by themselves establish a treatment effect either. The Wilcoxon test uses the rank ordering of observations, whereas the posted arm summaries describe medians and the middle half of scores. Individual observations are not posted in the registry record, so the test cannot be independently reproduced from the listed summaries.
The primary outcome counts are 47 and 43, while the trial enrollment is 100. The registry record does not explain the participant flow or the handling of missing primary outcome data. This limits assessment of how representative the analyzed participants are of all randomized participants. Overall, the posted data describe the recorded scores and a nonsignificant rank-based comparison, but do not provide the effect estimate, uncertainty interval, or analysis details needed for a fuller assessment.
9. Statistical Methods Explained
The primary outcome is summarized with medians and interquartile ranges, and the registry reports a Wilcoxon (Mann-Whitney) comparison. These methods address different aspects of the data: the summaries describe each arm, while the test compares the distributions of observations through their ranks.
What does the Wilcoxon comparison assess?
As a general explanation, the Wilcoxon rank-sum test, also called the Mann-Whitney test, combines observations from the groups, ranks them, and assesses whether observations in one group tend to be higher or lower than observations in the other. It does not require the outcome to follow a normal distribution. Its interpretation as a test of a difference in medians requires additional assumptions, such as similarly shaped distributions; without those assumptions, it is more accurately understood as a comparison of distributions or rank tendency. The registry record does not report whether those assumptions were assessed.
The posted p-value is 0.328. A p-value is calculated relative to a null hypothesis and a test procedure. In general, a larger p-value means the data are less inconsistent with that null model than a smaller p-value would be; it does not show that the groups are identical. A p-value also does not convey the range of plausible effect sizes. That is why an effect estimate and confidence interval are useful complements. Neither is reported for the primary comparison in the registry record.
How should the medians and ranges be read?
The median is the middle observation when scores are ordered. The interquartile range runs from the lower quartile to the upper quartile and describes the central spread. These summaries are useful when a distribution may be skewed or contain unusually high or low scores. They do not show the full distribution, and they cannot reproduce a rank-based test without the underlying participant-level data. The registry record does not post those data.
What does an equivalence label require?
Equivalence is a prespecified statistical claim that the difference between groups is small enough to fall inside an acceptable range. As a general explanation, this requires an equivalence margin defined before examining the results and an analysis that evaluates whether the confidence interval for the contrast lies within that margin. A conventional test that fails to reject a null hypothesis of no difference is not, by itself, an equivalence test. The registry labels the reported analysis as equivalence, but the margin, confidence interval, and detailed testing procedure are not reported in the registry record. The label alone therefore does not permit a reader to verify an equivalence conclusion.
What can the secondary planning illustrations tell readers?
The posted planning illustrations use a binary secondary outcome and are based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are explicitly planning illustrations, not observed power and not the trial's original design justification. For planning for 100% of the observed effect, the figures are 986 participants per arm for 80% power and 1,319 participants per arm for 90% power. For planning for 75% of the observed effect, they are 1,748 and 2,339 participants per arm, respectively. For planning for 50% of the observed effect, they are 3,920 and 5,247 participants per arm, respectively. These values depend on the observed effect used as the planning reference; they do not establish what sample size the investigators originally intended or whether the primary endpoint was adequately powered. The original sample-size justification is not reported in the registry record.
As a general statistical point, binary outcomes can be compared using quantities such as a risk difference, risk ratio, or odds ratio. The selected measure determines how an effect is expressed. For binary secondary outcomes, recalculated estimates based on posted summary counts are unadjusted; they do not replace a sponsor's own analysis when that analysis is posted. The registry does not report sponsor analyses for the listed secondary result described in the posted results.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Wilcoxon (Mann-Whitney) | not reported | 0.328 |
The primary result recorded by the sponsor is the Wilcoxon (Mann-Whitney) comparison, with p = 0.328, for pain while active at 18 hours. The registry does not report a primary contrast estimate or confidence interval alongside that test. The arm medians and interquartile ranges describe the observed scores, but they are not enough to reconstruct the participant-level rank calculation, so there is no directly comparable recalculation of the primary test in the posted results.
The secondary binary outcome has unadjusted recalculated comparisons based on its posted arm counts. No sponsor-reported analyses are listed for that secondary outcome, so those calculations should be distinguished from the sponsor's primary analysis. They are simple comparisons from summary data and do not incorporate any adjustment or additional modeling not represented in those summaries. The registry reports no discrepancy between a sponsor analysis and a recalculation. Where a sponsor's analysis is available, it remains the trial's own analysis; recalculated summaries are supplementary and should not be treated as a substitute for an analysis based on the full trial data.
The registry record does not describe the sponsor's detailed statistical plan, the exact implementation of the primary test, or the analysis population used. Those omissions limit independent assessment of how the recorded primary analysis was conducted.
11. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary outcome and a broad set of secondary outcomes. The record does not report whether the investigators adjusted for multiple comparisons, specified a hierarchy among secondary outcomes, or distinguished confirmatory from exploratory analyses. As a general statistical concern, evaluating many outcomes without adjustment can increase the chance of at least one apparently unusual result even when there is no underlying effect. Without the analysis plan, the weight given to individual secondary findings cannot be assessed fully.
Enrollment is recorded as 100. The primary endpoint results are recorded for 47 participants in the IV acetaminophen arm and 43 in the saline arm. The registry record does not explain the participant flow, the reasons primary endpoint data are absent for some enrolled participants, or whether the analysis followed intention-to-treat, per-protocol, or another population definition. The handling of missing data, including any imputation or sensitivity analysis, is not reported in the registry record.
The registry also does not report the sample-size justification for the primary endpoint, any interim analyses, or a detailed statistical analysis plan. The sample-size planning illustrations associated with a secondary outcome are explicitly not the trial's own design justification. These gaps make it difficult to determine whether the primary analysis followed a prespecified plan, how much precision was anticipated, or whether decisions about outcome inclusion were made before results were examined.
These omissions do not invalidate the recorded medians or the reported p-value, but they limit the ability to assess risk of bias and the strength of secondary claims. A complete participant flow, defined analysis populations, missing-data methods, and a prespecified approach to multiplicity would help clarify how the posted results should be interpreted.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| IV Acetaminophen | 0 | 50 | 0.0% |
| Saline | 0 | 50 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| IV Acetaminophen | 0 of 50 |
| Saline | 0 of 50 |
The adverse-event record lists 50 participants at risk for serious adverse events in each arm. It records 0 serious adverse events in the IV acetaminophen arm and 0 in the saline arm. It also records 0 other adverse events among 50 participants at risk in each arm. Death counts are not reported in the registry record.
These are descriptive counts for the safety groups recorded in the registry. They should not be interpreted as proof that the treatments have identical safety profiles or that no adverse events occurred outside the categories and reporting period represented in the record. The trial's safety follow-up duration and detailed definitions of the adverse-event categories are not reported in the registry record.
As a general statistical point, observing no events in a finite group does not establish that the underlying event risk is zero. The precision of a safety comparison depends on the amount of information available, including the number of participants and the length and completeness of follow-up. The registry provides no confidence interval or comparative safety analysis for these counts. The primary outcome analysis uses different recorded participant counts; the relationship between those outcome populations and the safety groups is not explained in the registry record.
13. What the Result Does, and Does Not, Mean
The registry records a median pain-while-active score of 42.0 mm in the IV acetaminophen arm and 50.0 mm in the saline arm at 18 hours after surgery. The reported Wilcoxon comparison has p = 0.328. These figures describe the posted primary outcome and its sponsor-reported test. They do not establish that acetaminophen changed pain, that the groups were equivalent, or that there was no difference.
The registry's equivalence label needs to be interpreted cautiously because the equivalence margin and confidence interval are not reported. A nonsignificant p-value is not evidence of equivalence, and the medians alone do not express the uncertainty in the between-arm contrast. The record also does not explain the difference between the enrollment count and the primary endpoint counts, or how missing data were handled. These limits matter when judging how broadly the recorded result can be applied to the randomized participants.
The trial's stated interests included postoperative pain and narcotic consumption, along with secondary measures related to side effects and rescue narcotic timing. The primary posted result concerns pain while active at one specified assessment time. It should not be treated as a complete account of pain at every time point, narcotic use, or safety. The registry does not provide complete results for every listed outcome, nor a reported multiplicity strategy that would support interpreting the secondary outcome family as a set of confirmatory tests.
In general, a randomized comparison can help estimate differences between assigned groups, but interpretation depends on the design, analysis population, outcome completeness, and precision. The registry record supports a description of the recorded primary scores and the reported rank-based test. It does not, on its own, establish a clinical recommendation or settle the broader effects of perioperative IV acetaminophen in this setting.
14. Why This Trial Matters Statistically
This trial is statistically informative because its primary measure is a patient-reported outcome summarized with a median and interquartile range, while the reported comparison uses a rank-based test. Understanding how those summaries and the test relate helps avoid treating a single p-value as a complete description of the data. The distinction is especially relevant when the registry labels an analysis as equivalence but does not report the margin and confidence interval needed to evaluate that claim.
The record also illustrates why outcome populations and participant flow matter. Enrollment is listed as 100, while primary endpoint results are recorded for 47 and 43 participants in the two arms. Without an explanation of missing observations or the analysis population, readers cannot determine how the analyzed data relate to the randomized cohort. This is a question of transparency and precision, not merely a bookkeeping detail.
The secondary outcomes raise a separate statistical issue: multiple outcomes can provide a broader view of a trial, but they also call for a prespecified interpretation strategy. The registry does not report a multiplicity approach or complete analyses for every listed secondary measure. Planning illustrations based on an observed secondary effect are useful as hypothetical design calculations, but they are not observed power and do not establish the original sample-size rationale.
Together, these features show why clinical trial results are best interpreted through the endpoint definition, descriptive summaries, inferential method, uncertainty, missing-data handling, and analysis plan. The posted primary result is one part of that evidence; the record's omissions define what can and cannot be concluded from it.
15. 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 limitations are specific to the information recorded for this trial. The primary endpoint is reported at a single assessment time, and the registry does not provide a primary between-arm effect estimate or confidence interval. The medians and interquartile ranges summarize the observed scores but do not reveal the full distributions or permit independent reproduction of the Wilcoxon test without participant-level data.
The record marks the primary analysis as equivalence but does not report an equivalence margin, confidence interval, or detailed procedure. Consequently, the reader cannot assess whether the analysis met an equivalence criterion. The original sample-size justification for the primary outcome is also not reported; planning illustrations for a secondary binary outcome should not be mistaken for that justification.
Primary endpoint results are recorded for 47 participants in one arm and 43 in the other, despite a total enrollment of 100. Participant flow, reasons for missing outcome data, analysis populations, and missing-data methods are not reported in the registry record. These gaps limit assessment of whether missingness could affect the comparison.
The registry lists multiple secondary outcomes but does not provide complete numerical results or sponsor analyses for all of them. It also does not report a multiplicity strategy or a hierarchy among outcomes. Safety counts are reported without a comparative confidence interval, detailed follow-up period, or death counts. The record does not report the full protocol, eligibility criteria, masking details, interim analyses, or a detailed statistical analysis plan. These limitations concern the completeness of the public record and restrict how confidently the posted results can be generalized or independently evaluated.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: RCT (Randomized Controlled Trial) of IV Acetaminophen for Post Operative Vaginal Reconstruction Pain — NCT02043704.
- Registry record last updated 2018-08-16; status last verified 2018-02.
- Results first posted 2018-03-14.
- 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.
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19. Record Summary
NCT02043704 is a completed Phase 4 randomized, triple-masked, parallel-group trial sponsored by TriHealth Inc. It enrolled 100 participants undergoing vaginal reconstructive surgery and compared perioperative IV acetaminophen with saline. The primary endpoint was self-reported pain while active 18 hours after surgery on a 0-100 mm visual analog scale. The registry reports medians of 42.0 mm and 50.0 mm, respectively, and a Wilcoxon (Mann-Whitney) p-value of 0.328.
The primary outcome is labeled as an equivalence analysis, but the registry record does not report an equivalence margin or confidence interval. Primary endpoint results are recorded for 47 participants in the acetaminophen arm and 43 in the saline arm; participant flow and missing-data methods are not reported. The record lists secondary outcomes and adverse-event counts, but does not include complete analyses for every listed outcome or a reported multiplicity strategy. These details define the scope of what can be concluded from the posted results.