Intravenous Dexmedetomidine for Cesarean Section: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Intravenous Dexmedetomidine for Cesarean Section (NCT03065530), a randomized phase 4 study. The primary outcome is Postoperative Pain Score (Visual Analogue Scale, VAS) at Rest.

2. Clinical Question

The clinical question includes both postoperative analgesia and breastfeeding, as reflected in the official title and study summary. The primary endpoint addresses pain at rest at a specified postoperative assessment, while the posted secondary outcomes include infant relative dose, another pain assessment, sedation, satisfaction, and nausea or vomiting. Those measures address different aspects of the study question and should not be treated as interchangeable evidence. The registry record does not report a single combined measure of analgesia and breastfeeding, nor does it report enough information to infer broader clinical consequences from the primary score alone.

3. Trial Design

The registry describes a completed Phase 4, randomized, quadruple-masked, parallel-group trial sponsored by The First Affiliated Hospital with Nanjing Medical University. The record lists enrollment of 120 and gives a start date of 2017-02-07 and primary completion date of 2017-09-30. Those are registry entries; they do not establish when every participant was assessed or how long the full study continued.

Four groups are represented in the posted primary outcome. Group C received saline, while Groups D1, D2, and D3 are the dexmedetomidine groups. Their listed postoperative infusion rates are 0.03ug/kg/h, 0.05ug/kg/h, and 0.08ug/kg/h, respectively. The arm descriptions also state that each active group received 0.5ug/kg intravenous dexmedetomidine diluted to 4ug/ml in 30 min, and 1mg butorphanol tartrate after delivery. The control description specifies saline in the same volume calculated by weight and 1mg butorphanol after delivery. All groups are described in the context of postoperative butorphanol analgesia.

The primary measure is postoperative pain at rest at 6h after cesarean section. The registry reports the mean and standard deviation for each group and an overall Kruskal-Wallis analysis. It does not report the randomization procedure, allocation concealment, masking roles, protocol deviations, or the statistical analysis plan. The label quadruple masking is recorded, but the record does not define which people were masked. The registry also does not report whether the planned enrollment was achieved under the trial’s own definition or why the posted arm-level denominators differ from the enrollment entry.

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: not meeting inclusion criteria (n=39) declined to participate , n=14 other reasons, n=3

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 Postoperative Pain Score (Visual Analogue Scale, VAS) at Rest, measured over 6h after cesarean section..

The primary endpoint is postoperative pain intensity at rest, assessed 6h after cesarean section using a visual analogue scale. The registry describes the scale as ranging from 0, no pain, to 10, the worst imaginable pain, and says assessment was made while the participant was in a supine position. The endpoint is reported as a group mean with a standard deviation, so it describes the average score and the spread of scores within each group.

Pain is a patient-reported experience, and a visual analogue scale gives a structured way to record its intensity at a defined assessment time. The at-rest condition matters: it distinguishes the recorded pain state from pain assessed during movement or another activity. A single time-specific score can support comparison between randomized groups, but does not describe the full course of postoperative pain, pain during activity, or every participant’s experience.

As a general statistical point, a mean provides a compact summary of a continuous measure, while the standard deviation describes how dispersed individual scores are around that mean. Neither summary indicates how scores were distributed, whether the average represents every participant similarly, or whether a difference is important to patients. The registry record does not report a threshold for a clinically meaningful change or a separate patient-level responder outcome.

7. Results Posted in the Registry

• Group D1: mean 2.90 versus 3.14 on control; difference -0.25 (95% CI -0.88 to 0.38), standardized effect d = -0.20; z-test p = 0.444.
• Group D2: mean 1.67 versus 3.14 on control; difference -1.48 (95% CI -2.12 to -0.84), standardized effect d = -1.21; z-test p = <0.001.
• Group D3: mean 1.25 versus 3.14 on control; difference -1.89 (95% CI -2.48 to -1.31), standardized effect d = -1.70; z-test p = <0.001.

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.

Relative Infant Dose (RID) of Dexmedetomidine

• 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:
  • Group D2: mean 0.20 versus 0.17 on control; difference 0.03 (95% CI -0.08 to 0.13), standardized effect d = 0.17; z-test p = 0.631.
  • Group D3: mean 0.37 versus 0.17 on control; difference 0.20 (95% CI 0.06 to 0.34), standardized effect d = 0.95; z-test p = 0.006.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Group D2 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Group D3 than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Postoperative Pain Score (Visual Analogue Scale, VAS) at Rest

• 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:
  • Group D1: mean 2.86 versus 3.29 on control; difference -0.43 (95% CI -0.95 to 0.09), standardized effect d = -0.43; z-test p = 0.105.
  • Group D2: mean 1.62 versus 3.29 on control; difference -1.67 (95% CI -2.14 to -1.20), standardized effect d = -1.85; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Group D1 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Group D2 than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Ramsay Sedation Score(RSS)

• 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:
  • Dexmedetomidine 0.03ug/kg/h Group: mean 2.17 versus 2.00 on control; difference 0.17 (95% CI 0.03 to 0.31), standardized effect d = 0.63; z-test p = 0.016.
  • Dexmedetomidine 0.05ug/kg/h Group: mean 2.14 versus 2.00 on control; difference 0.14 (95% CI 0.01 to 0.27), standardized effect d = 0.56; z-test p = 0.031.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Dexmedetomidine 0.03ug/kg/h Group than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Dexmedetomidine 0.05ug/kg/h Group than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes extend beyond the primary pain score. The registry lists relative infant dose of dexmedetomidine, pain at rest at another assessment time, Ramsay sedation score, satisfaction, and nausea or vomiting. The outcome list repeats Ramsay sedation score, and the record states that 17 secondary outcomes are posted among 18 outcome measures. The posted details therefore represent only part of the planned outcome set, and the registry does not provide a complete account of every secondary measure in the registry record.

At a broad level, these outcomes address different domains: analgesia, sedation, infant exposure, satisfaction, and tolerability. They can help describe the range of questions the trial considered, but they do not combine into one overall result. A result on a pain score cannot by itself answer a question about infant exposure or satisfaction, and a sedation score does not substitute for a direct assessment of pain or breastfeeding.

The secondary results should be read alongside, not as a replacement for, the primary result. The posted secondary summaries show that patterns can differ across measures and assessment times. The registry record does not report a comprehensive prespecified hierarchy, multiplicity correction, or complete analyses for all listed outcomes. Unadjusted secondary findings therefore carry less weight as confirmatory evidence: when many outcomes and comparisons are examined, some apparently notable results can arise by chance, and selective availability can make the overall pattern difficult to judge.

The registry record also does not report a complete interpretation of how the secondary results relate to the primary endpoint or whether any secondary outcome was designated as confirmatory. The outcomes are best regarded as additional descriptive evidence that may inform further questions, rather than as independent proof of a broad effect on every aspect of postoperative recovery or breastfeeding.

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

• Relative Infant Dose (RID) of Dexmedetomidine
• Postoperative Pain Score (Visual Analogue Scale, VAS) at Rest
• Ramsay Sedation Score(RSS)
• The Degree of Satisfaction
• Number of Participants That Experienced Nausea or Vomiting
• Ramsay Sedation Score(RSS)
• Ramsay Sedation Score(RSS)
• Ramsay Sedation Score(RSS)

9. Statistical Interpretation

10. Statistical Methods Explained

The posted primary result combines descriptive summaries with an overall test. Each group’s result is expressed as a mean and standard deviation. The mean is the arithmetic average of the recorded pain scores; the standard deviation describes the variation of those scores around the average. These summaries help characterize the groups, but they do not show the full distribution, the presence of outliers, or whether the scores cluster in particular parts of the scale.

What does the reported overall test address?

The registry reports a Kruskal-Wallis test for the primary outcome across Group C, Group D1, Group D2, and Group D3, with p < 0.05. As a general explanation, the Kruskal-Wallis test is a rank-based method for assessing whether observations across multiple independent groups are consistent with a common distribution. It uses the ordering of observations rather than requiring the analysis to compare group means directly. Its result is an omnibus assessment: a sufficiently small p-value indicates evidence of some group difference, but does not tell which groups are different or how large any pairwise difference is.

The test is not itself a statement about the clinical importance of a difference. Nor does its p-value describe the probability that a treatment effect is true. It measures how compatible the observed test result is with the test’s null model, subject to the analysis assumptions. The registry record does not report diagnostic checks, a post-hoc comparison procedure, or a multiplicity adjustment following the overall test.

What do the recalculated contrasts mean?

The pairwise recalculations compare each dexmedetomidine group with Group C using the posted means, standard deviations, and group sizes. The reported metric is an unadjusted mean difference: the mean in the dexmedetomidine group minus the mean in the control group. A negative estimate therefore corresponds to a lower posted group mean in the dexmedetomidine group. The confidence interval expresses uncertainty around that estimated difference under the recalculation’s assumptions.

These calculations are not the reported Kruskal-Wallis analysis. They use summary statistics to give simple, unadjusted pairwise comparisons, while the reported test is rank-based and addresses all four groups together. The registry record does not report the sponsor’s pairwise estimates. Since the discrepancy flag is true, the sponsor’s own analysis takes precedence; the recalculated estimates should be read as supplementary descriptions rather than as a substitute for the sponsor’s inference.

As a general statistical point, a two-group mean comparison based on summary data relies on assumptions about how the group means and their uncertainty can be represented. The recalculated standard errors use the reported group sizes and standard deviations. The registry does not report whether the sponsor used a comparable model, adjusted for any covariates, or handled the outcome differently. A difference between an omnibus rank test and unadjusted mean-based pairwise calculations is not inherently a contradiction: they ask different questions and use different features of the data.

How should p-values and intervals be read?

A p-value is a measure of compatibility between data and a specified null hypothesis, under a statistical model. A smaller p-value is not a measure of effect size, precision, or clinical importance. An unadjusted p-value for an individual contrast does not account for the fact that several comparisons may be considered. This matters when readers inspect multiple endpoints or contrasts, because the opportunity for a chance finding increases as more tests are interpreted without a prespecified plan or correction.

A confidence interval gives a range of values compatible with the observed data under the method used. Its width reflects precision: a narrower interval gives a more concentrated range of estimates, while a wider interval leaves greater uncertainty. An interval that includes zero for a mean difference is compatible with no mean difference at the stated confidence level, but it may also include nonzero values. An interval that excludes zero does not by itself establish that the difference matters clinically or that the model is appropriate.

General statistical considerations also include independence of observations, measurement quality, missingness, and the form of the outcome distribution. Random allocation can support fair comparisons when it is implemented as intended and analyses preserve the randomized groups, but the registry record does not provide enough detail to assess those conditions. It does not report the analysis population, missing-data handling, exclusions, or whether the primary analysis followed an intention-to-treat principle.

Finally, the outcome is bounded by the scale’s endpoints, so its values cannot extend beyond the stated 0-to-10 range. A mean and standard deviation do not reveal whether a ceiling or floor pattern affected a group, and the record does not report distribution plots or individual-level values. These limitations are reasons to interpret the means and model-based contrasts as summaries of the reported results rather than as a complete account of participant experiences.

11. Confidence Intervals and Precision

The primary group means are accompanied by standard deviations, which describe within-group spread, not uncertainty in the group mean. For uncertainty about a contrast, the recalculated 95% confidence intervals are more directly relevant. For D1 versus C, the interval runs from -0.876 to 0.384. It spans zero, so the recalculation does not pin down the direction of the mean difference with much certainty. For D2 versus C, the interval is -2.115 to -0.841; for D3 versus C, it is -2.475 to -1.311. Both are below zero in these unadjusted calculations.

As a general explanation, a confidence interval represents the range of effect estimates compatible with the data and the calculation method at the stated confidence level. It is not a guarantee that the true value lies within that particular interval, nor does it show the range of individual participants’ scores. Its width depends on the amount of information and variability in the data, among other factors. A comparatively narrow interval can still be affected by bias, an inappropriate analysis, or selective reporting.

The recalculated intervals are based on small arm-level samples as recorded in the outcome summaries: Group C has n = 28, Group D1 has n = 29, Group D2 has n = 29, and Group D3 has n = 28. The record does not provide individual observations, alternative interval methods, or the sponsor’s pairwise confidence intervals. The reported overall Kruskal-Wallis test has no accompanying effect estimate or interval in the record. Therefore, the recalculated intervals convey uncertainty about simple mean differences but do not resolve uncertainty about the sponsor’s complete analysis or the clinical importance of the result.

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 are participants per arm, not total events. They are illustrations based on the observed effect, not the trial’s original design calculations. The assumptions recorded for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The calculation uses the stated fraction of the observed effect as the effect to detect. The trial’s own original sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the estimated participants per arm for a future two-arm study to have an 80% chance of detecting the specified effect under those assumptions, if that effect is real and the model assumptions hold. The 90% power column gives the corresponding per-arm planning figure for a 90% chance. These are design probabilities for a hypothetical study, not probabilities that the present result is correct. The planning figures are not observed power.

Each planning row considers a different fraction of the observed effect: 100%, 75%, or 50%. A smaller target effect requires more participants per arm to distinguish it from random variation at the same significance and power assumptions. This is why planning for 75% or 50% of the observed effect generally calls for larger per-arm figures than planning for 100%.

Observed effects from small studies can be imprecise and may be larger or smaller than effects in future research. The planning figures therefore should not be read as definitive enrollment recommendations. They are illustrations of how the sample-size requirement changes when the assumed effect size changes; they do not account for unreported design features, missing data, multiplicity, or a clinical threshold for a meaningful effect. For time-to-event outcomes, the registry’s planning description refers to total events, but the outcomes discussed in these displayed comparisons are continuous and the relevant figures are participants per arm.

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 = -0.246; pooled standard deviation σ = 1.207.
2. n = 2 × (1.96 + 0.842)² × 1.207² / -0.246² = 377.8, rounded up to 378 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 <- -0.246                      # observed difference in means
sigma <- 1.20675998969442                     # 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(3065530)
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 = 378 (80% power), 506 (90% power)
 75% of observed effect: n per arm = 672 (80% power), 900 (90% power)
 50% of observed effect: n per arm = 1,512 (80% power), 2,023 (90% power)
power.t.test: 378.7 
Simulated power at n = 378 per arm: 0.797 (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. Analyses Reported by the Sponsor

The registry’s reported primary analysis is a Kruskal-Wallis test across the four groups, with p < 0.05. That is the sponsor-reported result available in the record. It is an overall, rank-based comparison and does not supply a group-specific mean difference, confidence interval, or pairwise p-value.

The additional pairwise mean differences and confidence intervals are recalculations from the posted group summaries. They are unadjusted and use a different approach from the reported omnibus test. The record marks a discrepancy, so the sponsor’s own analysis takes precedence. The recalculations should not be presented as corrections to or replacements for the sponsor’s result.

The registry record does not report the sponsor’s detailed statistical analysis plan, any sponsor-conducted pairwise analysis, or the reason for the discrepancy. It is therefore not possible to determine from the record whether differences reflect a choice of estimand, method, analysis population, missing-data handling, or another aspect of the original analysis. The appropriate reading is to retain the sponsor’s reported overall finding while treating the recalculated contrasts as supplementary descriptions of the posted means and their uncertainty. They do not establish which pairs the sponsor concluded differed.

15. Multiplicity, Missing Data and Analysis Populations

The reported primary analysis is an overall Kruskal-Wallis test across four groups. The recalculated pairwise comparisons examine each dexmedetomidine group against Group C, and the registry lists multiple secondary outcomes and assessment times. Each additional test creates another opportunity for a chance finding. When several results are interpreted together, unadjusted p-values do not control the overall probability of a false-positive conclusion across the family of tests.

The registry record does not report a multiplicity strategy, such as a prespecified testing hierarchy or adjustment procedure. It does not identify which secondary outcomes were confirmatory, whether all listed outcomes were analyzed, or whether any analyses were exploratory. The reported overall p-value should therefore be distinguished from the unadjusted pairwise recalculations and from the many secondary comparisons that may be considered.

Missing-data handling is also not reported in the registry record. The posted sample sizes vary across outcome summaries, but the record does not explain why, whether any observations were missing, whether participants were excluded, or how missing measurements were treated. No analysis population is specified, including whether analyses followed intention-to-treat, per-protocol, or another definition. These details matter because exclusions or missingness related to outcomes or group assignment can affect the validity of comparisons.

The registry does not report the randomization sequence method, allocation concealment, or sufficient detail about masking procedures to assess implementation. Nor does it report a protocol or statistical analysis plan in the registry record. Without those details, it is not possible to determine whether outcome timing, analysis choices, and reporting followed prespecified decisions. These gaps limit confidence in interpreting secondary findings and in assessing whether the posted analyses capture all randomized participants and all planned outcomes.

16. 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 4.4% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports zero serious adverse events in each group, and zero deaths in each group. For other adverse events, it reports 1 affected participant in Group C, 2 in Group D1, 1 in Group D2, and 1 in Group D3. These are the reported group counts; they should be read with the at-risk counts recorded for each group and not as a complete description of the type, timing, severity, or duration of events.

The record does not list serious adverse event terms, and it does not provide details about the other reported events in the registry record. It also does not report how events were collected, whether events were considered related to treatment, or the time period covered by safety monitoring. A reported count of zero serious events is not evidence that no risk exists; rare events may not appear in a study of this size, and a registry count cannot establish comparative safety on its own.

These figures describe the safety information posted in the registry record, not a complete safety assessment. They should be interpreted in light of the limited event detail and the absence of a reported analysis plan for safety outcomes.

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

The posted primary summaries show lower average pain-at-rest scores in Group D2 and Group D3 than in Group C at 6h, while the mean in Group D1 is closer to the control mean. The registry’s overall Kruskal-Wallis analysis reports p < 0.05. Taken together, these are statistical descriptions of the reported groups and outcome time; they do not, by themselves, establish a clinically important benefit or a particular patient’s likely experience.

The overall test does not identify which groups differ. The recalculated pairwise estimates are unadjusted, and the discrepancy flag means the sponsor’s own analysis takes precedence. The record does not report sponsor-conducted pairwise estimates or a clinical importance threshold. Statistical evidence of a group difference and clinical importance are separate questions: the first concerns how the data compare with a statistical model, while the second asks whether the size and consequences of a difference matter in practice.

The findings also do not establish an effect on all postoperative pain, pain during movement, breastfeeding success, infant health, or long-term outcomes. The primary endpoint is a single assessment of pain at rest. Secondary outcomes address some additional questions, but the record does not provide complete reporting for every listed outcome or enough detail to determine a comprehensive effect on breastfeeding.

Randomization and masking are recorded design features, but their implementation and the analysis population are not described in sufficient detail to assess all potential sources of bias. The posted arm sizes are limited, and the registry does not report individual data, missingness, or how the original analysis handled these issues. Accordingly, the result is best treated as evidence about the reported trial measurements, with uncertainty about precision, analysis choices, and broader applicability. It is not a basis for medical advice or a guarantee of outcomes for individuals.

18. Why This Trial Matters Statistically

This trial raises several statistical questions that matter in clinical research. First, it compares multiple treatment groups while reporting one overall primary test. An omnibus test can indicate that results vary across groups, but it does not identify which specific contrast drives that finding. Pairwise estimates and an appropriate plan for multiple testing are needed to make more detailed claims without overstating chance findings.

Second, the registry presents a rank-based overall analysis alongside recalculated mean differences. These methods summarize and test different features of the data. Making that distinction explicit helps prevent a descriptive recalculation from being mistaken for the sponsor’s inferential result. Here, the discrepancy flag makes that distinction especially important, and the sponsor’s analysis takes precedence.

Third, pain is measured on a bounded patient-reported scale at a defined time and condition. Reporting the mean and standard deviation gives useful group-level information, but it cannot fully describe score distributions or individual experiences. Confidence intervals add information about precision for recalculated contrasts, while a clinically meaningful threshold would be needed to interpret the importance of a score difference; that threshold is not reported.

Finally, the registry’s secondary outcomes span distinct domains, and the record does not report complete multiplicity, missing-data, or analysis-population details. These are not merely technical omissions: they shape how confidently readers can interpret a collection of outcomes. The trial illustrates why transparent reporting of prespecified analyses, participant flow, and uncertainty is essential when interpreting results from a multi-arm clinical study.

19. 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 in this registry record. The population description is limited: the record identifies cesarean section and related conditions but does not report detailed eligibility criteria, participant characteristics, or a fuller description of the enrolled population. The listed enrollment is 120, while the primary outcome has arm-level denominators of 28, 29, 29, and 28; the registry does not explain the relationship between the enrollment entry and these outcome denominators.

The primary endpoint is limited to pain at rest at 6h. Although a later pain assessment is listed as a secondary outcome, the record does not provide a complete longitudinal account of pain or a measure of pain during activity. The primary outcome description does not state a clinically important difference threshold. The record also does not report the sponsor’s pairwise primary estimates or the rationale for the discrepancy flag.

Reporting of secondary outcomes is incomplete in the available record: 17 secondary outcomes are posted among 18 outcome measures, and the listed outcome names include repeated sedation entries. The registry does not report a complete multiplicity strategy, analysis population, or missing-data procedure. It does not provide enough detail to assess whether all randomized participants were included in the analyses.

Safety reporting is similarly limited. The posted counts lack event descriptions and details of collection, follow-up, and treatment relatedness. The record does not report the randomization method, allocation concealment, masking roles, or protocol deviations. These missing details restrict assessment of bias, precision, reproducibility, and the extent to which findings apply beyond the reported measurements.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Intravenous Dexmedetomidine for Cesarean Section — NCT03065530.
• Registry record last updated 2020-01-13; status last verified 2020-01.
• Results first posted 2020-01-13.
• 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.

23. Record Summary

NCT03065530 is a completed Phase 4 randomized, quadruple-masked, parallel-group trial sponsored by The First Affiliated Hospital with Nanjing Medical University. The registry lists enrollment of 120 and compares saline with dexmedetomidine at 0.03ug/kg/h, 0.05ug/kg/h, and 0.08ug/kg/h, alongside butorphanol-based postoperative analgesia.

The primary outcome is mean VAS pain at rest 6h after cesarean section. The registry reports a Kruskal-Wallis result of p < 0.05. Recalculated pairwise mean differences are unadjusted; because the discrepancy flag is true, the sponsor’s own analysis takes precedence. The registry record does not report the sponsor’s pairwise estimates, a multiplicity strategy, missing-data handling, or a detailed analysis population.

Selected secondary outcomes concern infant relative dose, pain, sedation, satisfaction, and nausea or vomiting. Safety counts report zero serious adverse events and zero deaths in each group, with limited detail about other events. Interpretations are constrained by incomplete reporting and the absence of individual-level data.