To Characterize the Performance of the Nasal Dilator Strip in Lowering Nasal Resistance During Sleep, Promoting Nasal Route Breathing and Reducing the Signs and Symptoms of Sleep Disordered Breathing in a Group of Chronic Nocturnal Nasal Congestion Sufferers Who Report Trouble With Their Sleep.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for To Characterize the Performance of the Nasal Dilator Strip in Lowering Nasal Resistance During Sleep, Promoting Nasal Route Breathing and Reducing the Signs and Symptoms of Sleep Disordered Breathing in a Group of Chronic Nocturnal Nasal Congestion Sufferers Who Report Trouble With Their Sleep. (NCT03105297), a randomized phase 2 study. The primary outcome is Nasal Resistance in Sleeping State : Nasal Resistance Phase.

2. Clinical Question

The broader study question included whether the strip could lower nasal resistance during sleep, promote nasal-route breathing, and reduce signs and symptoms of sleep disordered breathing. The record lists additional outcomes concerning sleep-related function, self-assessment, sleepiness, snoring, and breathing route. Those outcomes give the study a wider exploratory scope, but their presence does not establish that any particular change was observed.

The main statistical question is therefore not whether a reported estimate is large or small; a primary estimate and its uncertainty are not reported in the registry record. The available description identifies what was measured and how the comparison was arranged, but does not support a conclusion about the direction, size, or precision of the nasal-resistance comparison.

3. Trial Design

This was a Phase 2, randomized, open-label, crossover study sponsored by GlaxoSmithKline. Enrollment was 91, and the study status is completed. The registry dates the study start to 2009-09-25 and primary completion to 2010-08-10. It lists sleep disordered breathing and nasal congestion as conditions.

The study proceeded through baseline, active-use, and nasal-resistance phases. At baseline, all participants wore a nasal dilator strip during a sleep-laboratory night on Day 1. During the active phase, all participants used the strip at home over a 1 month period and returned for sleep-laboratory nights after 7 days on Day 8 and after 28 days on Day 29. Thus, the baseline and active phases do not provide a concurrent no-strip group as described in the record.

For the nasal-resistance phase, participants were randomized to one of two treatment sequences: strip followed by no strip, or no strip followed by strip. The sequence was applied over two sleep-laboratory nights, on Day 30 and Day 31. This crossover structure means that each participant could contribute measurements under both conditions, although the registry record does not report the outcome-level participant counts or explain how the paired measurements were analyzed.

Masking is listed as none. The record does not report further details about sequence generation, allocation concealment, washout procedures, or whether the analysis accounted for period or sequence effects. Those details should not be inferred from the crossover label alone. The study lists 26 outcome measures and four analyses, but the record does not provide a complete account of the statistical procedures for those analyses.

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: 103 participants were screened, out of which 9 were screening failure, 3 did not want to participate. Remaining 91 participants were included in the safety population.

Baseline Phase (Day 1)

Reasons for not completing this period:

Active Phase (Day 2-29)

Nasal Resistance Phase (Day 30, 31)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Per protocol population included all participants who fully complied with all study procedures and restrictions. Here, number of participants analyzed "N" signifies participants who were evaluable for this outcome measure and number analyzed signifies participants who were evaluable for the specified categories.

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: Safety population N=91, All participants to whom the study treatment was dispensed were considered evaluable for the safety population.

6. Primary Endpoint

The registry lists the primary outcome as Nasal Resistance in Sleeping State : Nasal Resistance Phase, measured over upto 2 days.

The primary endpoint is mean nasal resistance while participants were asleep during the nasal-resistance phase. The unit is centimeter (cm) H2O/liter/sec, and the registry identifies the dispersion measure as standard deviation. Measurements were made with a nasal mask and flow meter, which recorded a trans-nasal pressure difference and nasal flow continuously over the sleep-laboratory nights on Day 30 and Day 31.

Nasal resistance is a physiological measure of resistance to airflow through the nose. In general, it can describe an aspect of nasal airflow, but it is not itself a direct measure of sleep quality, daytime functioning, or the full experience of sleep disordered breathing. The registry’s wider set of secondary outcomes reflects that distinction: it also lists measures concerning sleep-related function, sleepiness, snoring, self-assessment, and nasal breathing route.

A mean describes the central level of a continuous measure across the analyzed observations. A standard deviation describes variation among those observations; it is not the uncertainty around the estimated mean. General statistical interpretation would usually consider an estimate alongside an appropriate measure of uncertainty and the analysis design. The registry record does not report the primary endpoint’s mean, standard deviation, comparison estimate, confidence interval, or p-value. Consequently, the endpoint’s observed magnitude and precision cannot be assessed from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The outcome is continuous, and the registry describes it using a mean and standard deviation. In general, a mean summarizes the average level of a measurement, while a standard deviation describes how dispersed individual measurements are around that average. A standard deviation is not a confidence interval and does not, by itself, indicate how precisely a treatment comparison has been estimated. The registry record gives no primary-outcome values, so neither the mean nor the variability can be interpreted numerically.

What does a crossover design contribute?

In a crossover study, a participant receives more than one condition over time. Here, the registry describes randomized sequences of strip and no strip across the two nights of the nasal-resistance phase. In general, comparing conditions within the same participant can reduce the influence of characteristics that remain stable over the study period. This does not remove all sources of uncertainty: changes over time, order of treatment, or effects persisting from an earlier condition may matter.

A crossover analysis commonly needs to account for the paired nature of observations rather than treating all measurements as independent. That is a general design consideration, not a description of the analysis used in this study. The registry record does not say whether a paired method was used, whether period or sequence effects were modeled, or whether carryover was evaluated. It also does not report a washout procedure. Without those details and the outcome results, the suitability and consequences of any particular analysis cannot be assessed.

What does the measurement represent?

The primary measure was nasal resistance while asleep, recorded continuously over the two nights with a nasal mask and flow meter. The device measurements involved trans-nasal pressure difference and nasal flow. In general, a physiological measure can provide information about a specific bodily process, while patient-reported or behavioral outcomes address different aspects of experience and function. The registry separately lists outcomes concerning sleep-related function, sleepiness, self-assessment, snoring, and breathing route. Those measures are complementary in concept, but the registry does not report their numerical results.

How should uncertainty be read?

In general, a confidence interval expresses a range of values compatible with the data under a specified statistical procedure, and its width conveys information about precision. A p-value addresses compatibility with a specified null model under the analysis assumptions; it is not a measure of effect size or clinical importance. Neither a confidence interval nor a p-value for the primary comparison is reported in the registry record. No effect estimate is reported either, so there is no result to assess for magnitude or precision.

The registry identifies standard deviation as the variability measure for the primary outcome. If a mean and standard deviation were available, they would describe the observations, but a comparison between conditions would still need an appropriate estimate and uncertainty measure. General interpretation should also take account of the crossover design and the population actually analyzed. The record does not provide enough detail to reconstruct these elements.

What do the planning assumptions mean?

The record describes planning illustrations based on a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is expressed as a fraction of the observed effect. These are assumptions for planning illustrations, not a report of the trial’s own design justification and not evidence of observed power. The record does not report the trial’s sample-size justification. It also does not provide the underlying primary effect estimate needed to interpret an illustration based on a fraction of that effect.

More generally, planning calculations estimate the sample size associated with assumptions about an effect, variability, allocation, and statistical procedure. Their results depend on those assumptions. They are not a retrospective measure of whether a completed study had enough power, and they do not replace reporting the observed estimate and its uncertainty. No numerical planning result is stated in the registry record.

How can over-dispersion matter?

Over-dispersion is a general concern for count outcomes when observed variation exceeds what a simple statistical model expects. Such a mismatch can make uncertainty estimates too narrow if the model is not adapted. This study’s primary outcome is a continuous resistance measure, not a count outcome, so over-dispersion is not the central issue for that endpoint. Some secondary outcomes concern snoring counts, but the registry record does not give their results or the models used. It would therefore be inappropriate to claim that over-dispersion was present or that a particular adjustment was made.

Finally, the record lists multiple outcomes and analyses but does not identify a complete statistical analysis plan. The statistical methods used for the posted results, if any, are not reported in sufficient detail to verify assumptions, reproduce estimates, or determine whether all planned analyses and outcomes are represented.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 26 outcome measures and four analyses. It does not report how those outcomes and analyses were grouped, which analyses were primary or secondary beyond the named primary outcome, or whether any adjustment for multiple comparisons was planned or used. In general, examining many outcomes can increase the chance of finding apparently notable results by chance, particularly when interpretation focuses selectively on favorable findings. A multiplicity strategy can address some of this concern, but the record does not report one.

The record also does not describe how missing outcome data were handled. It does not state whether participants with incomplete measurements were excluded, whether any imputation method was used, or whether sensitivity analyses assessed the effect of missingness. These details matter because analyses based on only observed measurements can be affected if missingness is related to participants’ outcomes or treatment experience. That is a general concern, not evidence that missing data biased this study.

The primary outcome population is described as per protocol, including participants who fully complied with study procedures and restrictions. The number evaluable for the endpoint is not reported in the registry record. The record does not provide enough detail to determine how compliance was defined, how many participants were excluded from the primary analysis, or how the per-protocol population related to the enrolled participants.

Safety counts are reported for phase-specific groups, while the primary outcome population is described separately. Those safety counts should not be treated as the primary analysis sample size. In general, the population used for an analysis should be identified alongside its estimate; the primary outcome estimate and its analyzed participant count are not reported.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: bell's palsy (1.4%).

The registry reports safety figures separately for baseline, active use, and the two nasal-resistance conditions. During baseline, 91 participants were at risk for serious adverse events and 0 were affected; 91 were at risk for other adverse events and 0 were affected. During the active phase, 70 were at risk for serious adverse events and 1 was affected; 70 were at risk for other adverse events and 28 were affected. No deaths are listed in these groups.

For the nasal-resistance phase, the strip condition lists 55 participants at risk for serious adverse events and 0 affected, and 55 at risk for other adverse events and 2 affected. The no-strip condition lists 55 at risk for serious adverse events and 0 affected, and 55 at risk for other adverse events and 1 affected. No deaths are listed for either condition. Bell's Palsy is the top serious adverse event term, listed as 1.4%.

These are registry counts for different study phases and conditions, not a complete account of event timing, severity, relatedness, or recurrence. The record does not provide enough detail to determine whether the active-phase serious event was considered related to the strip. The figures should not be combined across periods or interpreted as a causal comparison without further information. They describe reported safety events; they do not establish whether the intervention caused an event or whether the conditions differed in overall safety.

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

The trial record describes an exploratory study of a nasal dilator strip and specifies a randomized crossover comparison of strip and no strip during sleep-laboratory nights. Its primary endpoint was mean nasal resistance while asleep, measured with a nasal mask and flow meter. This information clarifies the target of the primary comparison and the general sequence of study activities.

It does not establish what happened to nasal resistance. The registry record does not report the means for the strip and no-strip conditions, a comparison estimate, or an uncertainty interval. Without those results, the direction and size of any difference cannot be evaluated, and the precision of an estimate cannot be judged. The record also does not report the number evaluable for the primary endpoint.

The study’s broader objectives concerned nasal-route breathing and signs and symptoms of sleep disordered breathing. Outcomes listed in the record include sleep-related function, self-assessment, sleepiness, snoring, and breathing route. Listing an outcome indicates that it was part of the study’s measurement scope; it does not show that a favorable or unfavorable change occurred. Numerical results for those measures are not reported in the registry record.

Likewise, completion of the study and enrollment of 91 participants do not, by themselves, demonstrate that the primary comparison was precise or conclusive. Precision depends on the observed data and the analysis, including the number of evaluable participants and variability. Those endpoint details are not reported.

The appropriate interpretation is limited to the design and outcomes documented in the record. The available information neither establishes a treatment benefit nor demonstrates an absence of an effect. It does not support a medical decision. A complete interpretation would require the primary and secondary outcome estimates, their uncertainty, analysis populations, and a fuller account of the statistical methods.

13. Why This Trial Matters Statistically

This study is statistically interesting because its primary comparison used a crossover sequence: participants were randomized to receive strip and no strip in different orders during the nasal-resistance phase. In general, this design can make within-participant comparisons possible, which is useful when measurements may vary substantially between people. It also makes the order and timing of conditions important to the analysis.

The endpoint is a physiological continuous measure recorded during sleep, while the study’s wider outcome set includes measures of sleep-related function, sleepiness, snoring, self-assessment, and breathing route. Considering these outcomes together can help distinguish a change in a measured physiological quantity from changes in other aspects of sleep and breathing. However, the registry lists outcomes without reporting their numerical results, so no such comparison of findings can be made.

The record also illustrates why design labels and objectives are not substitutes for analysis details. A randomized crossover description does not specify how paired observations, period effects, sequence, or possible carryover were handled. The record does not report those methods. It lists 26 outcome measures and four analyses but does not explain how multiplicity was addressed. These omissions limit a reader’s ability to assess the statistical basis for any conclusions.

Most importantly, the primary numerical result is not reported in the registry record. Without the estimate, variability, uncertainty, and analyzed participant count, it is not possible to assess the magnitude or precision of the primary comparison. The study therefore matters as an example of how design and measurement can be described even when the results needed for statistical interpretation are unavailable.

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 most important limitation of the registry record is that it does not report numerical primary-outcome results. Means, standard deviations, a treatment comparison, confidence intervals, p-values, and the primary analysis sample size are not given. The direction, magnitude, and precision of the primary result therefore cannot be assessed.

The primary population is described as per protocol, meaning participants who fully complied with study procedures and restrictions, but the number analyzed is not reported. The record does not fully explain the criteria for inclusion in this population or how exclusions were handled. This makes it difficult to relate the primary analysis to the 91 participants enrolled.

The crossover design raises analysis questions that the registry record does not answer. It does not describe washout procedures or explain how paired measurements, period effects, treatment sequence, or possible carryover were handled. Masking is listed as none. The record does not provide sufficient detail about outcome measurement processing or assessment procedures to evaluate their possible influence.

The study lists 26 outcome measures and four analyses, but does not report a full statistical plan or a multiplicity approach. Missing-data methods are also not reported. These gaps limit assessment of whether the posted outcomes represent all planned analyses and how incomplete observations may have been addressed.

Finally, safety data are listed by phase and condition, but detailed event descriptions, timing, relatedness, and the handling of events across periods are not reported. The primary completion date and completed status do not resolve these limitations in the outcome reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: To Characterize the Performance of the Nasal Dilator Strip in Lowering Nasal Resistance During Sleep, Promoting Nasal Route Breathing and Reducing the Signs and Symptoms of Sleep Disordered Breathing in a Group of Chronic Nocturnal Nasal Congestion Sufferers Who Report Trouble With Their Sleep. — NCT03105297.
• Registry record last updated 2019-07-26; status last verified 2019-05.
• Results first posted 2019-07-26.
• 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

NCT03105297 is a completed Phase 2 randomized, open-label crossover study sponsored by GlaxoSmithKline. It enrolled 91 participants with chronic nocturnal nasal congestion who reported trouble sleeping. All participants used a prototype nasal dilator strip during baseline and over a 1 month active phase. During the nasal-resistance phase, randomized sequences assigned strip and no-strip conditions across sleep-laboratory nights on Day 30 and Day 31.

The primary outcome was mean nasal resistance while asleep, measured with a nasal mask and flow meter and reported in centimeter (cm) H2O/liter/sec. The registry identifies standard deviation as the dispersion measure and describes the primary population as per protocol. The number analyzed and the numerical primary results are not reported in the registry record. The record lists 26 outcome measures and four analyses, but does not provide a complete statistical analysis plan or missing-data and multiplicity methods. Safety counts are reported by phase and condition; no deaths are listed.