Effectiveness of Mometasone Nasal Irrigation for Chronic Rhinosinusitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of Mometasone Nasal Irrigation for Chronic Rhinosinusitis (NCT03705793), a randomized phase 4 study. The primary outcome is Change in Sino-Nasal Outcome Test Scores (SNOT-22).

2. Clinical Question

The trial asked whether mometasone furoate delivered by large-volume, low-pressure nasal irrigation differed from mometasone nasal spray in its effect on symptoms and related quality of life among surgery-naive patients with chronic rhinosinusitis. The primary outcome was change in Sino-Nasal Outcome Test scores from baseline to Week 8. The record also lists a Clinical Global Impression measure and nasal endoscopic findings as secondary outcomes.

The SNOT-22 captures symptoms and social or emotional consequences associated with rhinosinusitis. Its score ranges from 0 to 110, with higher scores representing worse outcomes. The registry record describes a randomized, double-masked, parallel-group Phase 4 study and an enrollment of 53. The posted primary outcome results include 24 participants in the irrigation arm and 23 in the spray arm. Those arm counts describe the reported outcome results; the record does not explain how they relate to enrollment or identify the analysis population.

3. Trial Design

The registry describes a randomized, double-masked, parallel-group Phase 4 trial sponsored by Washington University School of Medicine. The study is marked completed. Its recorded start date is 2019-01-01, and its primary completion date is 2020-02-15. Enrollment is listed as 53.

Participants were assigned to mometasone furoate nasal irrigation or mometasone nasal spray. Each arm description pairs the active treatment with a placebo delivered through the other route, consistent with the recorded double masking. The irrigation arm used mometasone furoate powder and placebo nasal spray; the spray arm used mometasone nasal spray and placebo nasal irrigation. The registry descriptions are truncated, so the full administration instructions and formulation details are not reported in the registry record.

The study summary identifies surgery-naive patients with chronic rhinosinusitis as the intended population. The registry also lists allergic rhinosinusitis and chronic eosinophilic rhinosinusitis as conditions. Age criteria, diagnostic thresholds, recruitment sites, and other eligibility requirements are not reported in the registry record.

The primary assessment was change in SNOT-22 score from baseline to Week 8. The registry lists two secondary outcomes: the number of participants scoring below 3 on the Clinical Global Impression Scale at Week 8, and change in nasal endoscopic findings using the Lund-Kennedy Grading System. Numerical results are posted for the Clinical Global Impression outcome, but numerical results for the endoscopic outcome are not reported in the registry record.

The outcome results list 24 participants for the irrigation arm and 23 for the spray arm on the primary and Clinical Global Impression outcomes. How participants were assigned, followed, excluded, or included in each analysis is not reported in the registry record. The allocation concealment method, masking assessment, and detailed visit schedule are also not reported.

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: Mometasone Furoate Nasal Irrigation Arm 3 participants lost to follow-up 2 participants withdrew Mometasone Nasal Spray Arm 4 participants lost to follow-up 1 participant withdrew While 53 participants were initially enrolled, a total of 7 participants were lost to follow-up and 3 participants withdrew. Thus, the total number of participants who completed the study was 43.

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.

Population: An intention-to-treat approach was used for all data analyses, which included all patients who were enrolled and randomized

6. Primary Endpoint

The registry lists the primary outcome as Change in Sino-Nasal Outcome Test Scores (SNOT-22), measured over Change from Baseline to Week 8.

The primary endpoint is change in Sino-Nasal Outcome Test scores (SNOT-22) from baseline to Week 8. The SNOT-22 asks participants to rate 22 symptoms and social or emotional consequences of rhinosinusitis. Each item is rated from 0 to 5, producing a total score from 0 to 110. Higher total scores represent worse outcomes.

A patient-reported measure can capture how symptoms affect a person’s experience, rather than relying only on clinical observations. Change from baseline focuses on how scores differ over the follow-up period, rather than on the Week 8 score alone. In general, change scores can help describe whether reported symptom burden moved over time, but interpretation depends on how the change is defined. The registry record does not state whether change was calculated as Week 8 minus baseline or baseline minus Week 8. Therefore, the sign of the posted estimate cannot be translated confidently into improvement or worsening from the record alone.

The registry reports least-squares mean changes with 95% confidence intervals for each arm. These are arm-level estimates. A direct estimate of the difference between arms, with its uncertainty or a primary-outcome p-value, is not reported in the registry record. Consequently, the posted primary results describe each arm’s estimated change and its precision, but do not by themselves quantify the between-arm treatment contrast.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a least-squares mean represent?

In general, a least-squares mean is a model-based estimate of an outcome mean. It can differ from a simple arithmetic average when a statistical model adjusts for other variables or uses a particular structure for the data. The registry identifies the primary endpoint statistic as a least-squares mean, but does not report the model, adjustment variables, covariance assumptions, or other details that would explain exactly how these estimates were obtained. The posted values should therefore be treated as the registry’s arm-level model-based results, not as means that can be independently reconstructed from the information recorded.

How should the confidence intervals be read?

In general, a confidence interval expresses the uncertainty associated with an estimate under a specified statistical procedure. A narrower interval indicates greater precision than a wider interval on the same scale. The primary results give a 95% confidence interval for each arm’s estimated change. These intervals do not directly answer whether the arms differ: that requires an estimate of the between-arm contrast and its own uncertainty. Separate arm intervals should not be used as a substitute for that contrast.

What is the distinction between an arm estimate and a treatment contrast?

An arm estimate describes the outcome within one assigned group. A treatment contrast compares outcomes between groups, using a defined direction such as spray relative to irrigation. A contrast can account for the uncertainty and, where applicable, the covariance structure of the group estimates. The registry posts arm-level primary estimates but does not report the primary contrast. No direct primary p-value or confidence interval for the treatment difference is reported in the registry record.

How does the secondary risk difference work?

For the Clinical Global Impression outcome, the posted comparison uses a risk difference. In general, a risk difference subtracts the proportion meeting an outcome in one group from the proportion in the comparison group; its sign depends on the stated order of groups. The reported estimate is for mometasone nasal spray relative to mometasone furoate nasal irrigation. Its confidence interval gives a range of values compatible with the recalculation under its assumptions. Because the interval includes zero, it does not establish a clear difference in either direction. The reported p-value is unadjusted, so it does not account for testing multiple outcomes or contrasts.

The risk-difference comparison is labelled recalculated. Such a recalculation is a simple, unadjusted analysis based on posted summary statistics; it is not necessarily the sponsor’s prespecified model. No discrepancy is flagged for this result. More generally, a recalculated result should not be presented as a replacement for a sponsor analysis if the two disagree.

What does over-dispersion mean in general?

Over-dispersion arises when observed variability is greater than a statistical model assumes. If a model underestimates variability, standard errors can be too small and confidence intervals too narrow. This concern is relevant to some count or event models, but the primary endpoint is continuous and is reported as a least-squares mean with a confidence interval. The registry record does not describe a count model, an over-dispersion assessment, or any adjustment for it. It would be inappropriate to infer such a procedure from the posted results.

What do the planning illustrations mean?

In general, a sample-size planning calculation asks how many participants might be needed to detect a chosen effect under specified assumptions. The registry’s planning illustration is based on the observed effect, uses equal allocation, a normal approximation, and a two-sided significance level of 0.05. It considers planning for 100%, 75%, and 50% of the observed effect. The resulting participant counts are planning illustrations, not the number enrolled, not the trial’s documented design justification, and not observed power. The registry record does not report that these assumptions were used to plan the trial or give a separate sample-size justification.

What analysis details remain unknown?

The registry does not report the primary analysis model, the direction used to calculate change, whether the analysis was adjusted for baseline score, how missing observations were handled, or which analysis population was used. It also does not report whether the analysis followed assignment regardless of treatment received. These omissions limit independent interpretation and reproduction of the primary analysis. General statistical explanations clarify what common estimates mean, but they cannot fill in analysis choices that are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record does not report a statistical analysis plan describing how outcomes were prioritized, how many comparisons were planned, or whether the primary analysis was adjusted for baseline or other covariates. It does not report an interim-analysis plan or stopping rules. These details should not be inferred from the fact that the study is marked randomized, double-masked, and completed.

The record identifies one primary outcome and two secondary outcomes. Numerical results are posted for the primary endpoint and one secondary endpoint; numerical results for the other secondary outcome are not reported in the registry record. A multiplicity adjustment, such as a method to control the overall chance of false-positive findings across multiple tests, is not reported. The posted p-value for the recalculated secondary comparison is unadjusted. It should not be interpreted as if it accounted for testing other outcomes.

The primary results list 24 participants in the irrigation arm and 23 in the spray arm, while overall enrollment is recorded as 53. The registry record does not explain the difference between the enrollment figure and outcome-specific counts. It does not say whether missing assessments, eligibility exclusions, withdrawals, or another analysis-population definition account for the different totals. These possibilities cannot be distinguished from the record.

Methods for handling missing SNOT-22 or secondary outcome data are not reported in the registry record. The record does not identify an intention-to-treat, per-protocol, or other analysis population, nor does it describe imputation or sensitivity analyses. Without this information, the effects of missing observations and analysis-population choices cannot be assessed from the posted results alone. The absence of these details is a limitation in interpreting the estimates, not evidence that any particular method was or was not used.

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 4% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: myocardial infarction (3.7%).

The safety results list serious adverse events among 26 participants at risk in the irrigation group and 27 in the spray group. There were no serious adverse events recorded in the irrigation group and one in the spray group. Myocardial infarction is listed as the top serious adverse-event term at 3.7%. No deaths are recorded in either group, and no other adverse events are recorded in either group.

These are descriptive counts from the registry record. A serious adverse event is not necessarily caused by the study treatment; the record does not report an attribution assessment or establish a causal relationship. The listed event term and percentage should be read as registry safety reporting, not as a comparative estimate of treatment-related risk. The record also does not provide enough detail to assess event timing, clinical course, or the investigators’ judgment about relatedness.

The safety figures should not be combined with the efficacy outcome counts: the at-risk numbers differ from the participants listed for the primary endpoint, and the reason is not reported in the registry record. With only the recorded counts and no further detail, these results describe what was reported but do not establish comparative safety.

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

The primary results describe estimated changes in SNOT-22 scores within each treatment arm from baseline to Week 8. They include 95% confidence intervals, which convey uncertainty around those arm-level estimates. The record does not report a direct comparison between irrigation and spray for the primary endpoint, so it does not provide the central quantity needed to estimate how the approaches differed on SNOT-22.

The direction of the change calculation is also not stated. Although higher SNOT-22 scores represent worse outcomes, the record does not say whether the reported change is follow-up minus baseline or baseline minus follow-up. The posted positive estimates therefore cannot be described reliably as improvement or worsening from this record alone.

The secondary Clinical Global Impression comparison is an unadjusted recalculation with an interval that spans no difference. It offers limited evidence about a difference between the arms, and numerical results for the other listed secondary endpoint are not reported in the registry record. The safety results record one serious adverse event in the spray group and none in the irrigation group, with no deaths reported. The registry does not establish whether the event was related to treatment.

These findings do not establish that one delivery approach is superior, equivalent, or interchangeable with the other. Absence of a reported primary contrast is not proof that there is no difference. Likewise, an interval that includes no difference does not demonstrate equivalence; equivalence requires a prespecified margin and an analysis designed to assess it, neither of which is reported in the registry record.

The findings also do not determine how results apply to patients outside the study population or to outcomes and time points not reported. The trial’s primary assessment is at Week 8, and longer-term results are not reported in the registry record. The information supports a cautious description of the posted estimates and their limitations, not a treatment recommendation.

13. Why This Trial Matters Statistically

This trial illustrates why arm-level estimates and treatment contrasts should be distinguished. The primary outcome reports a least-squares mean change and confidence interval for each arm, but no direct between-arm estimate. Readers can see the uncertainty around each group’s result, yet cannot use those results alone to determine the size or precision of the difference between delivery approaches.

It also shows why endpoint definitions matter. SNOT-22 has a clear scale interpretation—higher totals are worse—but the sign convention for change is not stated. A numerical change estimate needs both the scale and the direction of subtraction to support a directional account. Without that definition, even an otherwise interpretable score can be difficult to translate into a plain-language description of change.

Another statistical issue is the distinction between planned design information and retrospective planning illustrations. A calculation based on the observed effect can illustrate how sample size depends on the effect one seeks to detect. It does not document the original design assumptions, and it is not observed power. The registry record does not report the trial’s own sample-size justification.

Finally, interpretation depends on complete reporting across outcomes and analysis choices. The record lists multiple outcomes, but does not report numerical findings for every listed secondary measure, a multiplicity strategy, missing-data methods, or the analysis population. Those omissions matter because they affect how confidently readers can compare outcomes and judge the robustness of estimates. Clear reporting of contrasts, change-score direction, analysis methods, and outcome availability would make the statistical evidence easier to evaluate.

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.

Several limitations specific to this record restrict interpretation. Most importantly, the registry reports arm-level primary SNOT-22 estimates but not a direct treatment contrast, confidence interval for that contrast, or primary p-value. The direction of the change calculation is also not reported, preventing a confident interpretation of positive values as improvement or worsening.

The outcome results include 24 participants in the irrigation arm and 23 in the spray arm, while enrollment is listed as 53. The record does not explain the difference or identify the analysis population. Missing-data handling, exclusions, withdrawals, and sensitivity analyses are not reported, so the potential influence of incomplete outcome data cannot be assessed.

The follow-up specified for the primary outcome is Week 8. Longer-term outcomes are not reported in the registry record. The record lists two secondary outcomes, but numerical results are not reported for the endoscopic outcome. The available Clinical Global Impression comparison is an unadjusted recalculation, and the record does not report multiplicity control or an outcome hierarchy.

The registry describes the study population as surgery-naive patients with chronic rhinosinusitis, but detailed eligibility criteria and demographic characteristics are not reported in the registry record. Further, the comparison is between two mometasone delivery approaches; it does not provide a comparison with no mometasone treatment. These features limit the scope of the conclusions that can be drawn from the posted results.

The statistical model for the primary least-squares means and the detailed trial analysis plan are not reported. Thus, the estimates cannot be independently reconstructed or checked against model assumptions from the registry record alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effectiveness of Mometasone Nasal Irrigation for Chronic Rhinosinusitis — NCT03705793.
• Registry record last updated 2025-06-26; status last verified 2025-06.
• Results first posted 2020-12-19.
• 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.

18. Record Summary

NCT03705793 is a completed, randomized, double-masked, parallel-group Phase 4 trial sponsored by Washington University School of Medicine. Enrollment is listed as 53. The study compared mometasone furoate nasal irrigation with mometasone nasal spray in surgery-naive patients with chronic rhinosinusitis.

The primary outcome was change in SNOT-22 score from baseline to Week 8. The registry reports arm-level least-squares mean changes and 95% confidence intervals, but not a direct comparison between arms; it also does not state the direction used to calculate change. One numerical secondary outcome is posted as an unadjusted recalculation, while numerical results for the listed endoscopic outcome are not reported in the registry record.

Important analysis details—including the primary model, missing-data handling, analysis population, and multiplicity approach—are not reported. Safety results record one serious adverse event in the spray group, none in the irrigation group, and no deaths in either group. The posted information supports descriptive interpretation, with substantial limits on conclusions about the primary between-arm difference.