Short (5 Days) Versus Long (14 Days) Duration of Antimicrobial Therapy for Acute Bacterial Sinusitis in Children: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Short (5 Days) Versus Long (14 Days) Duration of Antimicrobial Therapy for Acute Bacterial Sinusitis in Children (NCT01166945), a randomized na study. The primary outcome is Proportion of Children With Clinical Relapse on Day 10 (Short Course) vs Day 20 (Long Course).

2. Clinical Question

The trial’s stated objective was to compare short-course and long-course antimicrobial therapy. Its brief summary says the investigators hypothesized that short-course therapy would lead to more frequent relapses and would not reduce resistant organisms. That statement describes the hypothesis, not a finding. The registry record does not report the observed relapse counts or proportions for either group, so the comparison cannot be answered from the posted primary outcome information.

The primary outcome title refers to clinical relapse, while its description specifies that children are classified as cured, improved, or having failed therapy according to symptom-survey scores. The two assessment times differ by treatment group: day 10 for the short course and day 20 for the long course. Thus, the clinical question combines outcome classification with group-specific assessment timing. The record does not provide a single reported contrast, estimate of uncertainty, or statistical test for that comparison.

A secondary outcome concerns the percentage of participants with antibiotic-resistant flora on day 30 compared with baseline. The registry record does not give results for that outcome either. The clinical questions are therefore clear as aims, but the posted results do not establish the direction or size of any treatment-group differences.

3. Trial Design

The registry identifies this as a randomized, parallel-group trial with triple masking. It lists the phase as NA and the condition as sinusitis. The sponsor is the University of Wisconsin, Madison. The record lists 98 participants enrolled, a start date of 2010-11, primary completion in 2016-02, and a completed status.

Participants were assigned to a short-course or long-course regimen. In the short-course description, amoxicillin-potassium clavulanate combination is given for 5 days and placebo for the next 9 days. In the long-course description, the antimicrobial combination is given orally for 14 days. These descriptions distinguish the duration of active treatment while including a placebo period in the short-course regimen. The record does not provide further information about how randomization was generated or how allocation was concealed.

Triple masking indicates that the registry labels the trial as masked at three levels, but the identities of those masked are not reported in the registry record. Further details about the masking procedures, the presentation of the placebo, or whether masking was assessed are not reported in the registry record. The record also does not describe stratification, sites, eligibility criteria, or the planned recruitment target beyond the enrollment figure.

The primary outcome was assessed at different times for the two groups: day 10 for the short-course group and day 20 for the long-course group. The outcome description says daily symptom surveys were used from day 1 to 14, followed by a daily survey from day 15 to 30. A total of 82 participants completed through day 20; the record attributes changes in participant numbers between day 10 and day 20 to Group A Strep diagnosis, non-compliance, and loss to follow up. It does not provide group-specific participant flow or explain which participants contributed to each outcome assessment.

Although the trial is marked completed, completion status alone does not indicate whether all planned outcomes were reported or whether the reported record contains a full account of the trial’s analyses. Arm-level primary outcome results and statistical analyses 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: A total of 98 subjects were consented and enrolled. A total of 82 subjects completed the study through day 30. Participants were evaluated on days 5, 10, 15, and 20 for the primary outcome.

Randomized

Reasons for not completing this period:

Day 5

Day 10

Reasons for not completing this period:

Day 15

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: 98 participants were enrolled, and 82 completed through day 20. Participant numbers change from day 10 to day 20 due to Group A Strep diagnosis, non-compliance, and lost to follow up over the course of the study.

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Proportion of Children With Clinical Relapse on Day 10 (Short Course) vs Day 20 (Long Course), measured over at 10 days and at 20 days.

The primary outcome is titled as the proportion of children with clinical relapse, assessed on day 10 for the short-course group and day 20 for the long-course group. The record’s outcome description explains that classification was based on symptom-survey scores rather than a separately described clinical event count. It defines three categories: cured, improved, and failed therapy.

The survey included 6 symptoms each day from day 1 to 14 and 3 symptoms each day from day 15 to 30. For symptoms present initially, a score of 2 was assigned; absent symptoms received a score of 0. The description gives a maximum entry score of 20 for persistent symptoms. Changes in symptom severity during treatment contributed +1, -1, or 0 for worsening, improvement, or no change, respectively. At the relevant assessment, children were classified as cured if they reached a score < 2. They were classified as improved if the score was at least 2 points lower than at day 5 for the short-course group or day 15 for the long-course group. They were classified as having failed therapy if the score worsened by + 3 between day 5 and day 10, or day 15 and day 20, respectively, or if it did not meet the improvement criterion.

Symptom-based classifications offer a structured way to describe clinical status using repeated observations. However, the registry title emphasizes relapse while the description specifies the three-category classification rules; the record does not explain how those categories were combined to produce a relapse proportion. The outcome results are not reported in the registry record, so the number or proportion in each category cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical details in a trial record determine how a research question is translated into an analysis. For this trial, randomization, parallel groups, and triple masking are recorded, but a detailed statistical analysis plan is not reported in the registry record. The reported outcome definition can be described, but it does not supply the missing analysis methods or numerical results.

What does the endpoint represent?

The primary outcome is described through three categories—cured, improved, and failed therapy—derived from symptom scores. This is a categorical outcome: each assessed child is assigned to a category according to the stated criteria. A comparison could report counts or proportions in those categories, or it could define a particular category or combination as the event of interest. The registry title refers to the proportion with clinical relapse, but the record does not explain how that phrase maps onto the three listed categories. The analysis used to derive a single relapse measure is not reported in the registry record.

General statistical explanation: a count records how many participants meet an outcome definition, while a proportion relates that count to the number of participants assessed. Interpreting a proportion requires knowing its denominator and how participants without an observed assessment were handled. Here, group-specific denominators and outcome counts at the relevant assessments are not reported, so no proportions can be interpreted.

What can an effect estimate and confidence interval tell a reader?

General statistical explanation: an effect estimate describes the size and direction of a comparison, while a confidence interval communicates the uncertainty around that estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but neither the estimate nor an interval alone resolves questions about study design, missing observations, or clinical relevance. No primary-outcome effect estimate or confidence interval is reported in the registry record.

A significance test, if reported, would address how compatible the observed data are with a specified null hypothesis under its statistical assumptions. A p-value does not measure the size or importance of an effect. No primary-outcome p-value or test result is reported in the registry record. The statistical plan, including the chosen test and any adjustment or covariate strategy, is also not reported in the registry record.

How should the different assessment times be considered?

The endpoint compares the short-course group at day 10 with the long-course group at day 20. The schedule also describes daily surveys from day 1 to 14 and a different daily survey from day 15 to 30. General statistical explanation: outcome timing is part of the estimand—the precise treatment effect a study aims to describe. If groups are assessed at different times, the comparison is not simply a contrast at one shared follow-up day. The record does not report a method for accounting for the difference in assessment timing, nor does it give additional outcomes that would permit a common-time comparison.

Repeated symptom measurements may be analyzed in several ways, depending on the research question and analysis plan. General explanation: a longitudinal method can use measurements over time and account for how observations from the same participant are related. The registry does not report whether such a method was used. It would be inappropriate to infer a repeated-measures analysis solely because daily symptom surveys were collected.

What do the planning assumptions mean?

The record describes a planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between the groups, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. This description characterizes assumptions for planning illustrations, not the trial’s own design justification. The registry record does not report the resulting participant counts for those illustrations, the observed effect on which they depend, or the trial’s sample-size justification.

General statistical explanation: sample-size calculations are planning tools that relate an assumed effect, variability or event frequency, significance level, and desired power to a required number of participants. A calculation based on an observed effect is an illustration, not a retrospective measure of the trial’s actual power. The record’s planning description does not establish that the trial was designed around those assumptions or that it had a particular probability of detecting an effect.

For a binary event, planning calculations typically depend on the assumed event frequency in each group and the contrast to be detected. Here, the primary outcome is described using multiple categories and different assessment times, and the observed outcome data are not reported. Therefore, the record does not permit an independent assessment of a planning calculation for the primary comparison. No extra values should be inferred from the assumptions alone.

What analysis details remain unavailable?

The registry record does not report the analysis population, the handling of missing outcome assessments, the statistical test for the primary outcome, covariate adjustment, or any interim analyses. It also does not report whether the planned analysis followed the randomized assignment regardless of treatment received. Those details can affect how results are interpreted, particularly when participant numbers change during follow-up.

General statistical explanation: an analysis based on assigned groups preserves the comparison created by randomization, while analyses based on treatment received or participants with complete follow-up can answer different questions and may be more vulnerable to differences between the analyzed groups. The record does not say which approach was used. With no group-specific primary outcome counts or analysis results, precision and statistical compatibility with different effect sizes cannot be assessed.

10. Multiplicity, Missing Data and Analysis Populations

The record lists a primary outcome with three possible classifications and assessments at different times for the two groups. It also lists a secondary outcome concerning antibiotic-resistant flora on day 30 compared with baseline. Multiple outcomes, categories, or assessment times can raise a multiplicity question: when several statistical tests are conducted, the chance of at least one apparently notable result can increase. General statistical explanation: a prespecified analysis plan can identify which comparisons are primary and whether adjustments or a hierarchy are intended. The registry record does not report a multiplicity strategy or a detailed statistical analysis plan.

The record describes the primary outcome at day 10 for the short-course group and day 20 for the long-course group. It also notes that the number of participants changes between day 10 and day 20 because of Group A Strep diagnosis, non-compliance, and loss to follow up. It does not give group-specific counts for those reasons, the denominators at each time, or the number with observed endpoint data. The primary outcome results and secondary outcome results are not reported in the registry record.

Missing data can affect an estimate when participants without observations differ from those with observations in outcome status or other relevant characteristics. General statistical explanation: complete-case analysis uses participants with the needed measurements, while other approaches may make explicit assumptions about missing outcomes. The registry record does not say which approach was used, whether missingness was examined, or whether sensitivity analyses were conducted. No analysis population is reported in the registry record, including whether all randomized participants were included in the primary comparison.

Because the outcome counts, denominators, and analysis details are absent, the potential effect of missing data and multiplicity cannot be quantified. The enrollment and completion figures describe overall participation, but they do not show how many participants contributed to each endpoint category or analysis.

11. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse events for Arm A and Arm B. For serious adverse events, the number affected is 0 in each group; the numbers at risk are 51 for Arm A and 47 for Arm B. Deaths are also listed as 0 in both groups. These are the serious-event and death counts recorded for the groups, rather than estimates of comparative risk or proof that no event occurred outside the record’s reporting.

The record also lists other adverse events: 44 participants affected among 51 at risk in Arm A, and 47 affected among 47 at risk in Arm B. It does not provide event descriptions in the listed safety summary. Arm A and Arm B are not explicitly mapped to the short-course and long-course arms in the registry record, so that mapping should not be assumed from these figures.

General statistical explanation: a count of zero serious events can be reassuring as a description of what was recorded, but it does not by itself establish equal safety or rule out uncommon harms. The precision of a safety comparison depends on the number observed, follow-up, ascertainment, and the definition of events. The registry record does not provide a comparative statistical analysis of these safety counts or additional details about ascertainment.

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

The record identifies a clinically focused question: whether clinical relapse differs between children assigned to a 5-day antimicrobial course and children assigned to a 14-day course. It also documents randomization, triple masking, the treatment descriptions, symptom-survey rules, and participant follow-up information. These details clarify what the investigators set out to compare.

They do not establish the result of that comparison. The registry record does not report the primary outcome counts by group, a treatment contrast, a confidence interval, or a statistical test. It is therefore not possible to say from the posted results whether relapse was more or less frequent in either group, or how precise any difference might be. The stated hypothesis is an expectation and should not be mistaken for an observed finding.

The distinction between statistical evidence and clinical importance is general: an estimated difference describes the magnitude of an outcome contrast, while its uncertainty describes how precisely that contrast is estimated. Both are needed to interpret a comparison. Neither is available for the primary endpoint in the registry record. The endpoint’s different assessment days also matter, because a day 10 assessment in one group is not the same follow-up point as a day 20 assessment in the other.

The registry lists a secondary outcome on antibiotic-resistant flora, but reports no result for it. The posted safety counts include zero serious adverse events and zero deaths in each listed group, alongside counts of other adverse events. Those figures describe the record’s safety entries; they do not substitute for the missing efficacy outcome data or support a treatment-effect conclusion.

Accordingly, the registry record is informative about trial structure and planned clinical questions, but incomplete for evaluating the primary statistical comparison. The absence of posted results should be distinguished from evidence that the groups were the same or different. No treatment recommendation follows from these registry entries.

13. Why This Trial Matters Statistically

This trial raises several useful statistical issues in a compact clinical setting. First, it compares treatment durations while assessing the primary outcome at different days for the two groups. That makes the timing of measurement part of the interpretation, not a minor administrative detail. A reader needs to know exactly which outcome and time contrast an analysis estimates before interpreting a treatment-group difference.

Second, the primary outcome is described as a set of symptom-based categories, while its title refers to a proportion with clinical relapse. Statistical analysis depends on how categories are converted into the target comparison. The registry record gives criteria for cured, improved, and failed therapy, but does not explain how those categories became the reported relapse measure. That gap illustrates why transparent alignment between an outcome definition and an analysis is important.

Third, follow-up is not complete for all enrolled participants through day 20. The record names Group A Strep diagnosis, non-compliance, and loss to follow up as reasons for changing participant numbers. Without group-specific flow and endpoint denominators, a reader cannot assess how the analyzed participants relate to those enrolled or how missing observations might affect a comparison.

Finally, the record is marked completed but does not report primary outcome results or analyses. A completed status and a defined hypothesis do not convey an effect estimate. For statistical interpretation, outcome counts, denominators, analysis methods, and measures of uncertainty are essential. Their absence prevents a conclusion about the primary comparison, while still allowing readers to identify what information a complete report would need to make the result interpretable.

14. 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 main trial-specific limitation for interpretation is that the registry record does not report the primary outcome results. It provides the endpoint rules but no group-specific counts for cure, improvement, or treatment failure, and no reported relapse proportion. It also provides no effect estimate, confidence interval, or test result. As a result, the primary comparison cannot be evaluated from the posted results.

The primary assessment occurs at day 10 for the short-course group and day 20 for the long-course group. Because the groups are evaluated at different times, the target comparison is not a same-day contrast. The record does not explain the rationale for these assessment times or describe an analysis accounting for their difference. It also does not state how the three outcome categories relate to the title’s relapse outcome.

Overall, 98 participants were enrolled and 82 completed through day 20. The record says participant numbers changed between day 10 and day 20 because of Group A Strep diagnosis, non-compliance, and loss to follow up, but does not give counts by reason or group. It does not report endpoint-specific denominators, handling of missing assessments, or the analysis population. These omissions limit assessment of participant flow and potential missing-data effects.

The record does not report detailed randomization procedures, the identities of those masked, the statistical analysis plan, interim analyses, or multiplicity handling. Its planning-illustration description does not supply the resulting sample-size figures or the trial’s own sample-size justification. The secondary outcome on antibiotic-resistant flora also has no posted results. These are limitations of the information in the registry record; they do not establish that the trial itself failed to conduct analyses or collect data.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Short (5 Days) Versus Long (14 Days) Duration of Antimicrobial Therapy for Acute Bacterial Sinusitis in Children — NCT01166945.
• Registry record last updated 2019-06-10; status last verified 2019-06.
• Results first posted 2019-06-10.
• 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.

18. Record Summary

NCT01166945 is a completed randomized, parallel-group, triple-masked trial sponsored by the University of Wisconsin, Madison. It enrolled 98 participants with sinusitis and compared amoxicillin-potassium clavulanate combination given for 5 days, followed by placebo for the next 9 days, with the combination given orally for 14 days. The record lists phase as NA.

The primary outcome concerns clinical relapse, assessed at day 10 for the short-course group and day 20 for the long-course group using symptom-survey classifications. The record says 82 participants completed through day 20 and attributes changes in participant numbers to Group A Strep diagnosis, non-compliance, and loss to follow up.

The registry record does not report the primary or secondary outcome results, statistical analyses, or a detailed analysis plan. It lists zero serious adverse events and zero deaths in both Arm A and Arm B, with other adverse-event counts also recorded. The mapping of those safety groups to treatment duration is not reported in the registry record.