Post Operative Sore Throat and Dexamethasone: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Post Operative Sore Throat and Dexamethasone (NCT01052038), a randomized phase 4 study. The primary outcome is Subjects Assessment of Sore Throat Pain at 24 Hours.

2. Clinical Question

The clinical question concerns a postoperative symptom that the registry describes as a common complaint. The trial’s stated rationale is that sore throat can contribute to morbidity and patient dissatisfaction, and that corticosteroids are commonly used perioperatively for other purposes as well. Those statements describe the study’s motivation; they do not establish what the trial results mean for clinical care.

The comparison has three groups, so its central question is not limited to whether any dexamethasone group differs from placebo. The registry reports an overall comparison across all groups and pairwise comparisons involving the higher dexamethasone dose. It does not report a sponsor pairwise test between placebo and the 0.05mg/kg group for the primary outcome. The results therefore support a more complete reading of the all-group pattern than of every possible dose-to-dose contrast.

The primary outcome is a patient assessment collected by investigator-initiated phone conversation at 24 hours following surgery. The record also lists sore throat at 3 hours as a secondary outcome. These measure related but distinct time points, and neither by itself describes the full course of postoperative symptoms. The record does not report further details about who was eligible, the clinical setting beyond the surgery type, or how outcomes were handled when an assessment was unavailable.

3. Trial Design

This was a prospective, randomized, double-blind, placebo-controlled trial, according to its official title. The registry classifies it as phase 4, triple-masked, and parallel-group. Enrollment was 120. The three groups were placebo, dexamethasone 0.05mg/kg, and dexamethasone 0.1mg/kg, with 40 participants reported in each group for the primary outcome.

The placebo was normal saline 100ml given as an intravenous infusion 30 minutes before surgery. The 0.05mg/kg dexamethasone dose was administered in 100 ml of sterile saline solution prior to surgery; the 0.1mg/kg dose was also administered in 100ml of sterile saline solution prior to surgery. The timing for the dexamethasone groups is not specified more precisely in the registry record. Although the record identifies triple masking, it does not explain which roles were masked or how masking was maintained.

The study began in 2010-01, reached primary completion in 2010-09, and is listed as completed. Northwestern University is named as sponsor. The record describes the trial as prospective, but the detailed protocol, allocation method, recruitment flow, and any deviations from the planned design are not reported in the registry record.

The primary endpoint was a sore-throat pain score at 24 hours, reported as a median and inter-quartile range. Secondary outcomes listed include quality of recovery at 24 hours, sore throat at 3 hours, opioid consumption at 24 hours, and hoarseness at 24 hours. The registry also lists five outcome measures and ten analyses. It does not report the rationale for the enrollment target, the assumptions used to choose it, or whether the trial used interim analyses.

Enrollment and outcome denominators should be read separately. The primary outcome results give 40 participants for each group, while the registry does not describe participant flow or explain whether every enrolled participant contributed to every outcome. Details on the analysis population, missing outcome data, protocol deviations, and handling of withdrawals are not reported in the registry record.

4. Participant Flow and Accounting

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

Before assignment: No subjects were lost or excluded after consent was signed and prior to allocation.

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 Subjects Assessment of Sore Throat Pain at 24 Hours, measured over 24 hours.

The primary endpoint was patients’ assessment of sore-throat pain at 24 hours after surgery. The score ranged from 1 to 5: 1 meant severe sore throat, while 5 meant no sore throat. An investigator initiated a phone conversation at 24 hours to obtain the assessment. The registry reports the endpoint as a median and inter-quartile range for each group.

This is a patient-reported symptom measure. It captures how participants assessed their sore throat at a particular postoperative time point, rather than an objective examination or a record of symptoms across the entire recovery period. The ordered scale also has a clear direction: higher scores correspond to less sore throat. That direction matters when interpreting differences between groups.

Using a median and inter-quartile range is a way to describe the central score and the middle portion of the observed scores without assuming that the scale behaves like a continuous measurement with evenly spaced values. In general, this can be useful when data are ordinal or their distribution is not well represented by a mean and standard deviation. The registry does not explain why this summary was selected or report the distribution of individual scores.

The endpoint is relevant to the trial’s stated question because sore throat is the symptom under study. Its limits are equally important: the posted result concerns the assessment at 24 hours, does not establish symptom duration or later recovery, and does not by itself measure overall satisfaction, quality of recovery, or the balance of benefits and harms.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is summarized using medians and inter-quartile ranges. A median identifies the middle of an ordered set of observations; an inter-quartile range describes the span covering its middle portion. These summaries are suited to an ordinal score such as the 1-to-5 sore-throat scale because they do not require the analyst to treat each step of the scale as an equal-sized change. The displayed group summaries are 4 (3 to 5) for placebo, 4 (3 to 5) for dexamethasone 0.05mg/kg, and 5 (4 to 5) for dexamethasone 0.1mg/kg.

The registry reports a Kruskal-Wallis test for the overall primary-outcome comparison. In general, this rank-based test assesses whether the distribution of observations differs across groups. It does not, by itself, identify which group pairs differ or quantify the size of each pairwise difference. The reported overall p < 0.001 is evidence against the test’s no-difference null, but a p-value is not the probability that the null is true and does not measure clinical importance.

For two primary-outcome comparisons, the registry reports Wilcoxon (Mann-Whitney) tests and a median difference (net). This rank-based method compares the ordering of observations in two groups rather than relying on a comparison of means. The reported comparisons are placebo versus 0.1mg/kg and 0.05mg/kg versus 0.1mg/kg. Each has a reported net median difference of 1, a 95% confidence interval from 0 to 2, and p < 0.001. The registry does not report the corresponding pairwise test for placebo versus 0.05mg/kg.

A confidence interval gives a range of values compatible with the data under the method used, while reflecting sampling uncertainty. It is not a guarantee that the true value lies in the interval, nor does it capture every source of uncertainty, such as differences between the trial population and other settings. The primary confidence intervals have 0 as their lower endpoint. The record does not describe the interval method or explain how it relates to the rank-based p-values, so the estimates and tests should be reported as the registry presents them, without inferring a further analysis.

The registry reports a corrected chi-squared test for the 3-hour secondary sore-throat outcome across the three groups, with p = 0.004. In general, a chi-squared test evaluates whether categorical outcome distributions differ among groups. The record does not state which correction was used. The test is an overall comparison; it does not alone identify every pairwise difference.

The risk differences for the two comparisons with placebo are unadjusted re-calculations from the posted counts. A risk difference expresses the difference between the proportions with the outcome in two groups; a negative value corresponds to fewer participants with sore throat in the dexamethasone group than in placebo. For 0.05mg/kg versus placebo, the recalculated risk difference is -0.175, with a 95% confidence interval from -0.391 to 0.041 and the unadjusted p-value of 0.117. For 0.1mg/kg versus placebo, it is -0.35, with a 95% confidence interval from -0.553 to -0.147 and the unadjusted p-value of 0.002. These are not adjusted analyses and are not substitutes for the sponsor’s analysis.

The sample-size illustrations use the observed secondary-outcome effect as a planning reference, not as evidence of observed power. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrations consider planning for 100%, 75%, or 50% of the observed effect. For the 0.1mg/kg comparison, the figures are 31, 56, and 127 participants per arm for 80% power, and 40, 74, and 170 participants per arm for 90% power. For the 0.05mg/kg comparison, the corresponding figures are 127, 226, and 505 participants per arm for 80% power, and 170, 302, and 676 participants per arm for 90% power. These are hypothetical planning estimates based on the observed effect; the trial’s own sample-size justification is not reported in the registry record.

For the 3-hour endpoint, the posted counts are 24 participants with sore throat in the placebo group, 17 in the 0.05mg/kg group, and 10 in the 0.1mg/kg group, with 40 reported in each group. The recalculated comparisons use those summaries and do not account for covariates or multiplicity. General statistical practice treats such unadjusted analyses as exploratory when many outcomes or comparisons are examined, unless a prespecified testing strategy supports stronger interpretation. The registry record does not report such a strategy.

10. Analyses Reported by the Sponsor

The primary results in the registry are sponsor-reported analyses: an overall Kruskal-Wallis test across the three groups and Wilcoxon (Mann-Whitney) tests for placebo versus 0.1mg/kg and 0.05mg/kg versus 0.1mg/kg. Those analyses report p < 0.001 for each test, with a net median difference of 1 and a 95% confidence interval from 0 to 2 for each pairwise comparison. They are not recalculations from the group medians and inter-quartile ranges.

The risk differences for the 3-hour sore-throat comparisons are simple, unadjusted re-calculations from the posted group counts. The registry’s sponsor-reported analysis for that outcome is instead a corrected chi-squared test across all three groups, with p = 0.004. The recalculated pairwise p-values of 0.117 and 0.002 answer different, narrower comparison questions and should not be substituted for the sponsor’s overall test.

No discrepancy is flagged between the posted results and the recalculated results. The methods and comparison sets differ, so their statistics need not match. The primary result is best read using the registry’s own rank-based tests and reported summaries; the recalculated secondary results offer unadjusted pairwise descriptions of the posted counts. The record does not provide enough detail to reproduce the sponsor’s test procedures independently or establish whether the analyses followed a prespecified statistical plan.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint, four secondary outcomes, five outcome measures, and ten analyses. Multiple outcomes and group comparisons can complicate interpretation because each additional test creates another opportunity to observe a small p-value by chance. The registry record does not report whether the analyses followed a prespecified hierarchy, whether p-values were adjusted for multiplicity, or how the primary and secondary tests were prioritized. The reported secondary pairwise p-values are explicitly unadjusted recalculations.

Missing-data handling is also not described. The record reports 40 participants in each group for the primary endpoint and for the 3-hour sore-throat counts, but it does not provide participant flow, the number assessed at each time point beyond those outcome denominators, or reasons for any unavailable assessments. It does not state whether missing outcomes were imputed, whether analyses used all randomized participants, or whether a different analysis population was used. These details are not reported in the registry record.

The record does not report a statistical analysis plan, the rationale for the enrollment target, a sample-size justification, or interim analyses. The planning illustrations based on observed secondary effects do not establish how the trial was designed or whether it had adequate power for its primary endpoint. They are planning estimates under stated assumptions, not observed power and not evidence that the study was sized using those assumptions.

Without those details, readers cannot determine whether all planned outcomes and analyses are represented in the registry results, whether analysis choices were made before outcomes were examined, or how sensitive the findings are to missing data and multiplicity. These are limits on what can be inferred from the registry record; they do not show that any particular procedure was or was not used.

12. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports zero serious adverse events in each group, with 40 participants at risk in each group. These figures describe the serious-event counts posted for the trial; they do not establish that serious harms are impossible or exclude events that were not captured or reported. The record does not provide serious adverse event terms because the serious-event terms list is empty.

Other adverse events were reported for 25 participants in the placebo group, 19 in the 0.05mg/kg group, and 18 in the 0.1mg/kg group, with 40 participants at risk in each group. The registry does not provide the event types, severity details, timing, or a statistical comparison for these counts. They should therefore be read as descriptive counts, not as evidence that one group had a more favorable overall safety profile.

Deaths are not reported in the registry record. The record’s safety information is limited to these group counts and does not give enough detail to assess the nature or clinical importance of individual events, or to compare the full balance of possible benefits and harms.

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

The posted primary results show higher sore-throat scores in the 0.1mg/kg group than in the other groups at the 24-hour assessment, with an overall rank-based test and two reported pairwise tests favoring that group’s score distribution. Because the scale’s higher values mean less sore throat, this is a difference in the direction of fewer symptoms on the reported measure. The registry’s summaries do not mean every participant in that group had no sore throat, nor do they describe how each individual’s score changed.

The score difference is specific to a patient-reported assessment at one time point after ambulatory laparoscopic gynecologic surgery. It does not establish the duration of symptoms, the effect at other times, or the result for other surgical settings or patient groups. The record does not report a threshold for what patients would consider an important difference, so statistical evidence should not be equated with a quantified degree of clinical importance.

The secondary 3-hour outcome points in a broadly similar direction for the higher dose in the unadjusted recalculation, but secondary analyses are subject to uncertainty and multiplicity concerns. Numerical results for the other listed secondary outcomes are not reported in the registry record. The safety counts also do not describe event types or provide a comprehensive evaluation of harms.

These results do not establish that dexamethasone works or does not work as a treatment, and they do not constitute medical advice. They describe what the registry reports from this trial and how precisely the reported comparisons are estimated. Interpretation beyond the trial requires information about study conduct, analysis choices, participant characteristics, and the relevance of this population and outcome to the question being considered. Much of that detail is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial illustrates why the choice and direction of an endpoint matter. A sore-throat score can be read correctly only by noticing that higher values indicate less sore throat. The median and inter-quartile range retain the ordinal character of the scale, while the rank-based tests compare the ordering of scores across groups rather than treating the score as an ordinary continuous measurement.

It also shows why overall and pairwise tests should not be conflated. The overall Kruskal-Wallis test addresses the three-group comparison, while the reported Wilcoxon tests address selected pairs. A significant overall test does not specify which pairs differ, and an incomplete set of reported pairwise tests does not support claims about every dose comparison. The reported pairwise intervals and p-values should be interpreted in light of their methods and the comparison set.

The 3-hour secondary outcome demonstrates the distinction between a sponsor-reported overall test and unadjusted pairwise re-calculations. They are not interchangeable, even when they use the same posted counts. The planning illustrations likewise serve a different purpose from trial results: they indicate hypothetical participants per arm under stated assumptions, not observed power and not the trial’s documented design rationale.

Finally, statistical interpretation depends on reporting beyond p-values. Missing-data methods, analysis populations, multiplicity procedures, outcome definitions, and a sample-size justification are not reported in the registry record. Their absence limits independent assessment of robustness. The trial is therefore a useful example of reading numerical results alongside their design and reporting context, while keeping conclusions within the information the record actually documents.

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.

The registry record gives limited detail about eligibility and participant characteristics. The primary outcome’s population field is blank, and further inclusion and exclusion criteria are not reported in the registry record. The results therefore cannot be assessed for how well the participants represent other clinical populations. The record identifies ambulatory laparoscopic gynecologic surgery but does not provide further setting details.

The primary score was collected through an investigator-initiated phone conversation at 24 hours. The record does not explain the exact interview procedure, whether assessors were masked, how the score was elicited, or how incomplete responses were handled. Although the trial is classified as triple-masked, the roles covered by masking and the procedures used to preserve it are not reported.

The registry reports medians and inter-quartile ranges but does not provide individual-level outcome distributions. It reports pairwise primary tests for comparisons involving the 0.1mg/kg group, but not for placebo versus 0.05mg/kg. The record does not explain the choice of these comparisons or describe multiplicity control. The primary confidence intervals have a lower endpoint of 0, while the reported p-values are < 0.001; their construction is not described, limiting independent interpretation of that combination.

Secondary information is also incomplete for interpretation. The record lists several other secondary outcomes, but their numerical results are not reported in the registry record. The 3-hour pairwise recalculations are unadjusted, and the registry does not describe a prespecified analysis plan. Participant flow, missingness, analysis populations, protocol deviations, and the sample-size justification are not reported. The safety counts lack event descriptions and do not include reported death figures.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Post Operative Sore Throat and Dexamethasone — NCT01052038.
• Registry record last updated 2012-05-02; status last verified 2012-04.
• Results first posted 2012-05-02.
• 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.

19. Record Summary

NCT01052038, titled “Post Operative Sore Throat and Dexamethasone,” is listed as a completed phase 4 randomized, triple-masked, parallel-group trial sponsored by Northwestern University. The official title describes a prospective, randomized, double-blinded, placebo-controlled study in ambulatory laparoscopic gynecologic surgery. Enrollment was 120; the record lists a start of 2010-01 and primary completion in 2010-09.

The trial compared placebo with dexamethasone 0.05mg/kg and 0.1mg/kg. Its primary outcome was the sore-throat score at 24 hours, measured on a 1-to-5 scale and summarized by median and inter-quartile range. The registry reports an overall Kruskal-Wallis test and selected pairwise Wilcoxon tests. A secondary sore-throat count at 3 hours is also reported, with an overall corrected chi-squared test and unadjusted recalculations for comparisons with placebo.

Safety reporting includes serious and other adverse event counts by group. Further details on analysis populations, missing data, multiplicity, sample-size justification, and several listed secondary outcomes are not reported in the registry record.