Study To Evaluate Efficacy And Safety Of An Additional Dose Of Celecoxib (YM177) In Patients With Post-Tooth Extraction Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study To Evaluate Efficacy And Safety Of An Additional Dose Of Celecoxib (YM177) In Patients With Post-Tooth Extraction Pain (NCT01062113), a randomized phase 2 study. The primary outcome is Efficacy Rate (Percentage) of Patient's Impression.

2. Clinical Question

The trial addressed whether patients with pain after oral surgery reported a favorable impression two hours after receiving an additional dose of celecoxib 200 mg, compared with an additional placebo dose. The primary outcome classified a participant’s impression as favorable when it was rated “Excellent” or “Good.” Ratings of “Fair” or “Poor” did not count toward the efficacy rate.

The registry describes a study of acute pain after lateral mandibular impacted third-molar extraction. It lists an additional-dose celecoxib group and an additional-dose placebo group for the primary comparison. The record also lists an initial-dose celecoxib 400 mg group in the safety results. It does not give full descriptions of the trial arms in the arm-description fields, so details beyond the listed treatments and outcomes are not reported in the registry record.

The primary comparison concerns the proportion of participants with an “Excellent” or “Good” impression, rather than a direct measure of pain intensity. Secondary measures include pain intensity on a visual analog scale and a measure described as differences in pain intensity between baseline and two hours after the additional dose. The registry also names pain-intensity categories, but their full results are not included in the posted secondary analyses.

3. Trial Design

This was a phase 2 randomized, double-blind, parallel-group study described in the registry title as multicenter. The registry lists an enrollment of 255 participants and a completed status. The study began in 2010-04, with primary completion in 2010-08. The record identifies pain as the condition under study and describes the comparison as an evaluation of an additional celecoxib dose against placebo after impacted third-molar extraction.

The primary efficacy comparison was between participants assigned to an additional celecoxib 200 mg dose and participants assigned to an additional placebo dose. The primary outcome was assessed two hours after that additional dose. Its analysis population was the full analysis set, defined in the record as randomized participants who received the additional dose and had at least one efficacy assessment after randomization. The primary outcome analysis includes 64 participants in the additional celecoxib group and 58 in the additional placebo group.

The record also lists an initial-dose celecoxib 400 mg group in the safety results, with 133 participants at risk for adverse events. It does not explain the relationship between this group and the primary efficacy comparison in sufficient detail to reconstruct the participant flow or all treatment sequences. The record does not report the original sample-size justification, allocation ratio, or detailed randomization procedures.

Double masking is recorded, but the registry does not specify which roles were masked or how masking was maintained. The record identifies a parallel model and randomized allocation, but does not report further protocol details such as stratification, site-level procedures, or interim analyses. These design details should therefore not be inferred from the trial’s general labels.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The full analysis set (FAS). This analysis set consisted of randomized participants who received the additional dose of the study drug and who were assessed for at least one efficacy endpoint after randomization.

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 Efficacy Rate (Percentage) of Patient's Impression, measured over 2 hours post-additional dose.

The primary endpoint was the efficacy rate of the patient’s impression, measured as the percentage of participants rating their impression “Excellent” or “Good” two hours after the additional dose. Participants recorded their impression by self-report in a diary. The other two listed categories were “Fair” and “Poor.” The endpoint therefore reduces a four-category patient-reported rating to a binary outcome: favorable (“Excellent” or “Good”) versus not counted as favorable.

This type of endpoint is used to summarize whether participants report a favorable overall impression at a specified time. It is distinct from a scale that quantifies pain intensity: it reflects the participant’s overall rating using the categories defined in the registry, not a measured change in pain units. A binary rate can be compared between groups as a difference in proportions, while the categories themselves retain more detail if reported separately.

The rate was calculated using the number assessed as “Excellent” or “Good” divided by the total number of participants, multiplied by 100. The record identifies the full analysis set as the analysis population. It does not state how missing diary ratings were handled, whether any additional rules were applied to the endpoint, or how participants with an assessment outside the two-hour timeframe were treated; those details are not reported in the registry record.

7. Results Posted in the Registry

• Additional Dose Celecoxib 200 mg: 64.1% (41/64) versus 25.9% (15/58) on control; risk difference 38.2 percentage points (95% CI 21.9 to 54.5), risk ratio 2.48 (1.54–3.97); unadjusted two-proportion 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.

Pain Intensity Measured by Visual Analog Scale (VAS)

• 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:
  • Additional Dose Celecoxib 200 mg: mean 35.80 versus 51.90 on control; difference -16.10 (95% CI -24.51 to -7.69), standardized effect d = -0.67; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Additional Dose Celecoxib 200 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Differences in Pain Intensity (PI) Measured by VAS Among Participants

• 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:
  • Additional Dose Celecoxib 200 mg: mean 33.40 versus 12.30 on control; difference 21.10 (95% CI 13.33 to 28.87), standardized effect d = 0.96; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Additional Dose Celecoxib 200 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary results extend the primary patient-impression outcome by considering pain intensity on a visual analog scale and a measure described as the difference in pain intensity from baseline to two hours after the additional dose. The listed secondary outcomes also include the number of participants in four pain-intensity categories. Across the two secondary comparisons with posted numerical analyses, the registry reports small p-values, and the unadjusted recalculations indicate between-group differences. The visual analog scale score at two hours is lower on average in the additional celecoxib group; the direction of the baseline-to-follow-up difference is harder to interpret because its sign convention is not reported.

These measures relate to the primary result but do not duplicate it. A patient’s categorical overall impression and a pain-intensity score assess different aspects of the experience. Similar statistical evidence across distinct outcomes can provide context, but it does not make the outcomes interchangeable or resolve uncertainty about how the difference measure was calculated. The registry’s named four-category pain-intensity outcome does not have a full numerical analysis in the posted results.

Unadjusted secondary results carry less weight when several outcomes are examined because each additional test creates another opportunity to observe a statistically notable result by chance. General explanation: multiplicity procedures can control the overall error rate across a family of tests, but the registry does not report whether the trial used such procedures or identify a prespecified hierarchy of outcomes. The posted secondary p-values should consequently be read as individual, unadjusted analyses rather than as evidence that a multiplicity-controlled claim was established.

The secondary findings are supportive descriptive evidence about related measures, not a replacement for the prespecified primary comparison. The record does not report enough detail about outcome hierarchy, missing assessments, or adjustment methods to determine how the secondary tests were incorporated into the trial’s formal conclusions.

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

• Number of Participants in Each Pain Intensity (PI) With 4 Categories
• Pain Intensity Measured by Visual Analog Scale (VAS)
• Differences in Pain Intensity (PI) Measured by VAS Among Participants

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary for analysis: each participant either met the registry’s favorable-rating definition or did not. A risk, or proportion, is the number with the outcome divided by the number assessed in the group. A risk difference subtracts one group’s proportion from the other’s. For this trial, the reported risk difference is expressed as 38.2 percentage points, comparing the additional celecoxib group with the additional placebo group. This is an absolute contrast between proportions, not a relative percentage increase.

What does a confidence interval express?

In general, a confidence interval describes the range of effect estimates compatible with the data and the assumptions of the method. A 95% confidence interval is not a guarantee that the true effect lies inside the interval, nor does it describe the range of individual participant outcomes. The registry reports a 95% interval for the risk difference. Its width is relevant because an estimate alone does not convey how precisely the group contrast has been estimated.

What does a p-value test?

In general, a p-value describes how surprising the observed data, or data more extreme, would be under a specified null hypothesis and analysis model. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The sponsor’s posted primary analysis used an asymptotic z-test for the risk difference and reported a p-value below < 0.001. The posted recalculation reports a p-value below 0.001. Both are small relative to commonly used testing thresholds, but the p-value alone cannot address bias, missing data, endpoint relevance, or multiplicity.

Why use a risk difference?

For a binary endpoint, the risk difference presents the absolute separation between group rates. It can be read directly in percentage points, making it useful for understanding how far apart the observed proportions are. Other relative measures can express the comparison differently, but their interpretation depends on the baseline risk. No relative measure is needed to understand the main registered comparison, and the effect should not be reduced to a single measure without considering the underlying group rates and their uncertainty.

How do the secondary continuous outcomes differ?

The registry lists pain intensity measured by visual analog scale in millimeters, reported as a mean with a standard deviation. A mean summarizes the group’s average score; a standard deviation describes variation among participant scores. For two independent groups, a mean difference compares their averages. The posted recalculation gives a negative mean difference for the two-hour visual analog scale outcome, because the additional celecoxib group’s reported mean is lower than the placebo group’s. The registry reports a two-sided t-test for this outcome.

The other posted continuous outcome is described as differences in pain intensity measured by visual analog scale between baseline and two hours after the additional dose. It is also reported as a mean with a standard deviation, and the registry reports a two-sided t-test. The record does not explain the sign convention or precise calculation used for this difference measure. Therefore, the direction of its mean contrast should not be translated into a clinical interpretation without more information about coding and calculation.

Why can over-dispersion matter?

General explanation: over-dispersion occurs when observed variability exceeds what a statistical model assumes. When a model underestimates variability, standard errors may be too small and confidence intervals too narrow, making evidence appear more precise than it is. The posted primary method is an asymptotic z-test for a risk difference, and the continuous secondary analyses use t-tests. The registry does not report an over-dispersion assessment or alternative variance model. There is no basis in the record to assert that over-dispersion occurred in this trial.

What is the role of the analysis population?

The registry defines the primary full analysis set as randomized participants who received the additional study dose and had at least one efficacy endpoint assessed after randomization. This definition determines who contributes to the primary analysis. In general, excluding randomized participants after allocation can affect the comparability established by randomization, depending on why participants are excluded and how many are affected. The registry does not give enough participant-flow or missing-data detail to assess that issue fully.

The sponsor’s primary analysis and the simple recalculation are not identical procedures in every respect. The recalculation uses posted summary statistics and is unadjusted; it is an aid for reading the available data, not a substitute for the trial’s analysis plan. The registry’s reported analysis should be distinguished from these recalculations, especially when their methods, confidence intervals, or handling of participants are not fully documented.

11. Confidence Intervals and Precision

The sponsor-reported primary risk difference is 38.2 percentage points, and its 95% confidence interval runs from 20.3 to 56.1 percentage points. This interval provides a range of plausible values for the group contrast under the assumptions of the reported analysis. Its lower and upper bounds are both positive, while the width shows that the estimate is not precise to a single value. The interval concerns the difference between group rates, not the range of individual ratings.

The primary group rates are based on 64 participants receiving additional celecoxib 200 mg and 58 receiving additional placebo. Those denominators are substantially smaller than the overall enrollment of 255, but the registry does not provide a complete participant-flow explanation. The analysis population is defined as randomized participants who received the additional dose and had at least one post-randomization efficacy assessment. How many participants were excluded at each step, and why, is not reported in the registry record.

Confidence intervals are informative alongside p-values because they show the scale and precision of effects compatible with the data. A small p-value does not make an interval narrow, and an interval does not establish clinical importance. The record does not report a clinically important threshold for the primary outcome. It also does not describe adjustments for multiple outcomes or explain whether the interval accounts for any such adjustments.

The continuous secondary outcomes have posted recalculated estimates and intervals, but their interpretation depends on the definitions and coding of each measure. In particular, the registry does not specify the sign convention for the baseline-to-follow-up difference outcome. Any precision statement about that contrast should therefore be kept separate from a claim about which direction represents improvement.

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 sample-size planning figures are participants per arm, not total event counts. They are illustrations based on the observed effect, rather than the trial’s original design calculations. The registry does not report the original sample-size justification or the assumptions used to plan enrollment.

The illustration assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers effects equal to 100%, 75%, or 50% of the observed effect. For each assumed effect, the display gives the number of participants per arm associated with 80% power and with 90% power. In plain terms, those power columns describe the planned chance of detecting the chosen effect under the stated model and assumptions if that effect were the true one.

The figures are not observed power and do not describe the power achieved by the completed trial. They are hypothetical planning results derived from the observed effect, so they can be unstable when the observed effect is imprecisely estimated. Smaller effects require more participants to reach the same target power under otherwise similar assumptions. The planning display should therefore be read as a set of conditional illustrations, not evidence that the study was designed with those exact targets or that the trial had a particular probability of success.

The assumptions are stated for equal allocation between two arms. They do not account for design features or analysis decisions that are not reported in the registry record, such as adjustments for multiple comparisons or loss to follow-up. These planning figures cannot replace the trial’s undocumented original sample-size rationale.

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

Worked calculation for this trial

1. Control proportion p₀ = 0.259; treatment proportion p₁ = 0.641; average p̄ = 0.450.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.7035 = 1.3789.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6496 = 0.5467.
4. n = (1.3789 + 0.5467)² / (0.3820)² = 25.4, rounded up to 26 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 <- 0.258620689655172                          # control proportion
p1 <- 0.640625                          # 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(1062113)
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 = 26 (80% power), 34 (90% power)
 75% of observed effect: n per arm = 45 (80% power), 60 (90% power)
 50% of observed effect: n per arm = 98 (80% power), 130 (90% power)
power.prop.test: 25.4 
Simulated power at n = 26 per arm: 0.805 (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.

14. Analyses Reported by the Sponsor

The registry’s sponsor-reported primary analysis compared the additional celecoxib 200 mg group with the additional placebo group using an asymptotic z-test for the risk difference. It reports a risk difference of 38.2 percentage points, a 95% confidence interval from 20.3 to 56.1 percentage points, and a p-value below < 0.001. The simple unadjusted recalculation from the posted group summaries gives a risk difference of 0.382 and a p-value below 0.001. The registry record does not flag a discrepancy.

The sponsor’s analysis is the trial-reported analysis; the recalculation is an independent, unadjusted reading of the posted summary statistics. The point estimates express the same group contrast on different scales: the sponsor reports percentage points, while the recalculation records the proportion difference. The recalculation is useful as a check on the basic comparison but cannot recover any unreported details of the original analysis.

The continuous secondary outcomes likewise have sponsor-reported two-sided t-test p-values and separate unadjusted recalculations. The registry does not provide sponsor-reported effect estimates or confidence limits for those t-tests. When a sponsor-reported analysis is available, it should remain distinct from a recalculation based only on summary data; neither resolves missing information about the protocol, analysis population flow, or multiplicity.

15. Multiplicity, Missing Data and Analysis Populations

The registry reports a primary endpoint and several secondary outcomes, including pain-intensity categories and visual analog scale measures. The posted results include numerical secondary analyses, but the registry record does not report whether the trial controlled for multiplicity, which outcomes formed a formal testing family, or whether a sequence of primary and secondary tests was prespecified. When many outcomes are tested, unadjusted p-values do not control the chance of at least one false-positive result across all tests. The secondary p-values should therefore be interpreted as individual analyses unless an adjustment is documented elsewhere in the registry record.

The registry defines the primary full analysis set as randomized participants who received an additional study dose and had at least one efficacy endpoint assessment after randomization. This definition is reported, but the record does not provide a participant-flow account showing how many randomized participants did not receive the additional dose or lacked an efficacy assessment. It also does not report how missing primary ratings were handled, whether missing values were imputed, or whether sensitivity analyses were conducted.

Missing-data methods can affect estimates if participants without observed outcomes differ systematically from those with observed outcomes. General explanation: analyzing only observed assessments may be reasonable under some assumptions, but those assumptions cannot be evaluated from a definition of the analysis population alone. The record does not report reasons for missingness or comparisons of included and excluded participants.

The record also does not report interim analyses, a detailed statistical analysis plan, or the original sample-size justification. These omissions limit the ability to assess whether outcome selection, stopping decisions, and analysis choices were prespecified. They do not establish that such procedures were or were not used; the relevant details are not reported in the registry record.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event results list zero participants with serious adverse events in each of the three groups: the initial celecoxib 400 mg group, the additional celecoxib 200 mg group, and the additional placebo group. The corresponding numbers at risk for serious events are 133, 64, and 58. These are registry counts for the listed groups and should be read with their denominators.

The record also lists other, non-serious adverse events in 25 participants in the initial-dose group, 13 in the additional celecoxib group, and 18 in the additional placebo group. The numbers at risk for these events are 133, 64, and 58, respectively. The registry does not provide event-level descriptions for these non-serious events in the listed results. It reports no serious adverse-event terms in the top serious terms field. Death counts are not reported in the registry record.

Zero recorded serious events in these groups is not proof that serious events could not occur, and the results do not establish a comparative safety profile beyond the observed counts. The record does not give details about adverse-event definitions, collection procedures, follow-up duration, or how events were attributed to treatment. The initial-dose group’s safety results are not the same population as the primary efficacy comparison, so the denominators should not be conflated.

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

The registry results show that the proportion rating their impression “Excellent” or “Good” two hours after an additional dose was higher in the additional celecoxib 200 mg group than in the additional placebo group. The reported risk difference is 38.2 percentage points, with a 95% confidence interval from 20.3 to 56.1 percentage points. This describes the observed contrast in the trial’s defined full analysis set and at its specified assessment time.

The result does not mean that every participant in one group had a favorable impression, or that every participant in the other group did not. The primary endpoint combines two categories and leaves the distinction between “Excellent” and “Good,” as well as between “Fair” and “Poor,” outside the main binary comparison. The record does not give the full distribution across all four categories in the posted primary result.

The comparison also does not by itself establish the clinical importance of the observed difference. The registry does not state a threshold for a meaningful difference in this patient-reported outcome. Nor does the result establish effects at times other than two hours, in other populations, or under other treatment conditions. It is a finding from a specific postoperative setting, treatment comparison, endpoint, and analysis population.

The secondary visual analog scale results provide related information but assess pain intensity rather than overall impression. Their interpretation is limited by the registry’s lack of detail about the calculation and sign convention for the baseline-to-follow-up difference measure, and by the absence of reported multiplicity procedures. The safety counts are descriptive and do not show that an event is impossible merely because none was recorded in the listed groups.

These statistical findings are not medical advice and do not establish what an individual should do. They describe the registry’s posted results and their uncertainty, while leaving important questions about missing data, analysis procedures, clinical importance, and generalizability unresolved.

18. Why This Trial Matters Statistically

This trial illustrates why an effect estimate, its uncertainty, and the analysis population all matter when interpreting a clinical comparison. The primary result is a difference in proportions, which can be expressed in percentage points and understood alongside the group rates. The 95% confidence interval gives a range of estimates compatible with the reported analysis, adding information that a p-value alone cannot provide.

It also illustrates the importance of distinguishing a patient-reported categorical endpoint from a measurement of pain intensity. The primary outcome condenses four diary categories into a favorable versus non-favorable rating. Visual analog scale outcomes retain a different kind of information, and the baseline-to-follow-up difference measure requires a clearly stated sign convention to interpret its direction. Outcomes that concern the same condition are not automatically interchangeable.

The registry record further shows why analysis populations and documentation matter. The primary endpoint uses a defined full analysis set, but the record does not reconcile that set with total enrollment or describe missing-data handling. It also does not report whether secondary tests were adjusted for multiplicity. Those omissions limit the strength of conclusions that can be drawn from the posted analyses, even when the reported comparisons have small p-values.

Finally, planning illustrations based on an observed effect should not be mistaken for the trial’s original design rationale or its achieved power. The registry’s original sample-size assumptions are not reported. Separating planning calculations, sponsor analyses, and summary-statistic recalculations helps readers see what each can and cannot establish.

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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

Several limitations are specific to the registry record. Although it lists total enrollment as 255, the primary comparison includes 64 participants in the additional celecoxib group and 58 in the additional placebo group. The full analysis set definition is available, but the record does not explain participant flow from enrollment through randomization, treatment receipt, and endpoint assessment. Reasons for any exclusions or missing primary ratings are not reported in the registry record.

The primary endpoint is based on a self-reported diary rating, and the analysis combines “Excellent” and “Good” into one favorable category. The posted primary results do not give the complete distribution among the four rating categories. The registry also does not report details of diary completion, assessment validation, or handling of ratings recorded outside the target time.

The baseline-to-follow-up visual analog scale difference is not fully defined in the record. Its sign convention and precise calculation are not reported, which limits interpretation of the direction of its numerical contrast. The registry lists a four-category pain-intensity secondary outcome, but does not include a full numerical analysis of that outcome among the posted results described.

The record does not report multiplicity control, the original sample-size justification, an interim-analysis plan, or a detailed statistical analysis plan. It also does not provide enough detail to assess masking procedures, allocation implementation, or adverse-event collection and follow-up. These omissions should be treated as undocumented information, not as evidence that a particular procedure was absent.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Study To Evaluate Efficacy And Safety Of An Additional Dose Of Celecoxib (YM177) In Patients With Post-Tooth Extraction Pain — NCT01062113.
• Registry record last updated 2021-02-02; status last verified 2021-01.
• Results first posted 2012-11-19.
• 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

The registry describes a completed phase 2 randomized, double-blind, parallel-group study of an additional celecoxib dose versus placebo for acute pain after lateral mandibular impacted third-molar extraction. Enrollment was 255. The primary outcome was the percentage with an “Excellent” or “Good” patient impression two hours after the additional dose, analyzed in the defined full analysis set.

The primary comparison included 64 participants receiving additional celecoxib 200 mg and 58 receiving additional placebo. The registry reports a risk difference of 38.2 percentage points, with a 95% confidence interval from 20.3 to 56.1 percentage points and a p-value below < 0.001. Secondary outcomes include visual analog scale measures. Safety results list zero serious adverse events in the three groups with posted counts.

The record does not report the original sample-size rationale, multiplicity procedures, detailed missing-data handling, or complete participant flow. These gaps constrain interpretation of the posted results and their generalizability.