Hypertonic Saline for Acute Bronchiolitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Hypertonic Saline for Acute Bronchiolitis (NCT01247064), a randomized phase 4 study. The primary outcome is Respiratory Assessment Change Score (RACS).

2. Clinical Question

The registry describes an emergency-department study of children who continued to have respiratory distress after initial albuterol therapy. The comparison was between two nebulized saline concentrations, with the normal-saline group serving as the active comparator. The primary endpoint combines a change in respiratory distress assessment with a standardized change in respiratory rate. A decrease in RACS represents improvement, so the direction of the group means matters when interpreting the reported result.

The question is specific to the short-term score at 1 hour. It is not a direct comparison of longer-term recovery, and the registry record does not report a primary endpoint beyond this assessment. Hospitalization and parental perception are among the posted secondary outcomes, but they address different aspects of the episode and should not be treated as interchangeable with the score. The record does not report additional eligibility details or a more complete description of the enrolled children.

3. Trial Design

The registry identifies this as a Phase 4, randomized, quadruple-masked, parallel-group trial. Children were assigned to nebulized 3% saline or nebulized 0.9% normal saline. The record lists 31 participants in each group for the primary outcome and an overall enrollment of 62. The sponsor was Children's Hospital of Philadelphia. The status is completed; the recorded start was 2010-10 and primary completion was 2011-12.

The study concerned acute viral bronchiolitis in children presenting to an emergency department. According to the brief summary, participants had persistent respiratory distress after an initial trial of nebulized albuterol. The registry identifies the primary assessment as change in RACS between baseline and 1 hour. This short timeframe describes the outcome assessment, not the full duration of participation or follow-up; those details are not reported in the registry record.

Random allocation supports a comparison between assigned groups, while masking is intended to limit the influence of knowledge of treatment assignment on care or outcome assessment. The registry labels the trial quadruple-masked but does not specify which individuals were masked, how allocation was generated or concealed, or whether masking was maintained. Further protocol details, including adherence procedures, are not reported in the registry record.

The record reports a two-sided t-test for the primary outcome. It does not report a sample-size justification, a prespecified statistical analysis plan, or details of the analysis population. Those omissions mean the reported group sizes and test can be described, but the design rationale and all analytic decisions cannot be reconstructed from the registry record alone.

4. Participant Flow and Accounting

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

Overall Study

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 Respiratory Assessment Change Score (RACS), measured over Baseline and 1 hour.

The primary endpoint is the Respiratory Assessment Change Score (RACS), measured from baseline to 1 hour. It combines change in the Respiratory Distress Assessment Instrument (RDAI) with a standardized change in respiratory rate. The registry describes respiratory-rate changes in increments of 10%: a change of 5% or less from baseline counted as 0 units, while a decrease or increase of 6% to 15% counted as improvement or deterioration of 1 unit, respectively. The overall score is the arithmetic sum of the RDAI change and the standardized respiratory-rate change.

A lower RACS represents improvement. Combining the two components gives a measure that reflects both the assessed respiratory distress and the change in respiratory rate, rather than relying on either component alone. This may be useful for describing short-term change in respiratory status, but the registry record does not explain why this measure was selected or report validation evidence for the score.

The posted group values are means, with 95% confidence intervals for each group. These intervals describe uncertainty around the group mean; they are not confidence intervals for the difference between groups. The record reports a separate two-sided comparison between groups, but does not provide a numerical estimate or confidence interval for that between-group difference. Therefore the direction of the observed group means and the reported test can be described, while the size and precision of the between-group contrast cannot be fully assessed from the reported primary statistics.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is a score measured on a scale, and the registry reports a mean for each group. A mean describes the average score change among the participants represented in that group’s outcome summary. It does not show how scores were distributed, whether the results were concentrated around the mean, or whether a small number of observations strongly influenced it. The registry does not provide the underlying participant-level scores or a measure of spread such as a standard deviation.

What does the confidence interval describe?

A confidence interval expresses uncertainty around an estimate under the statistical method used to construct it. The posted 95% confidence intervals are for the mean RACS within each group. Their endpoints give a range of values compatible with the observed data and the method’s assumptions. They are not ranges containing a fixed proportion of individual children’s scores, and they are not intervals for the treatment-group contrast. The registry does not report a confidence interval for the between-group difference, which limits direct assessment of the precision of that comparison.

What does the t-test contribute?

The registry reports a two-sided t-test for the primary comparison. In general, a two-sided test evaluates evidence for a difference in either direction rather than testing only for a difference favoring one group. The reported p-value is 0.01. It indicates how unusual a result at least as incompatible with the null comparison would be if the null model and test assumptions were appropriate. It is not the probability that the null is true, a measure of effect size, or a guarantee that the observed pattern will reproduce.

For a t-test of means, statistical properties depend on features of the outcome data and the analysis. General considerations include the independence of observations and whether the method handles the groups’ variability appropriately. The registry record does not report diagnostic checks, the exact variance assumption, or additional model adjustments. Therefore the test can be identified as reported, but its implementation cannot be independently assessed in full from the record.

Why does the score’s direction matter?

For RACS, a decrease signifies improvement. That definition is essential because negative values are not automatically adverse or favorable without knowing the scale’s direction. The posted mean in each group is negative, and the normal-saline group’s mean is more negative. This describes the observed direction of change. The test result addresses evidence of a difference between groups; it does not establish the cause of that difference or its importance to patients.

How should secondary comparisons be read?

For binary outcomes, such as hospitalization or parental perception, a proportion describes the share of participants with the recorded outcome. A risk difference expresses the difference between two such proportions, with its sign depending on the order of groups used. General interpretation also considers uncertainty: when a confidence interval for a difference includes zero, the data are compatible with values on either side of no difference under that method. The posted secondary comparisons include unadjusted re-calculations from summary statistics, while the registry also reports its own tests. These are not replacements for a prespecified analysis plan.

The record’s sample-size illustrations are planning calculations based on the observed effect, not observed power and not evidence that the trial was designed to detect that effect. In general, planning calculations estimate the sample size needed under specified assumptions, including a target effect and statistical method. The registry states that its illustrations use a two-sided significance level of 0.05, equal allocation, a normal approximation, and fractions of the observed effect. Such illustrations are sensitive to those assumptions and should not be read as an explanation of the trial’s original enrollment target. The original sample-size justification is not reported in the registry record.

More generally, wider intervals indicate less precision than narrower intervals, while a p-value alone does not convey precision or importance. Statistical inference is also affected by missing observations, analysis choices, and multiplicity. Those aspects are not fully described in this record, so interpretations should remain tied to the posted outcomes and the methods explicitly reported.

10. Analyses Reported by the Sponsor

The registry’s own primary analysis is a two-sided t-test and reports p = 0.01. The posted means and their group-specific 95% confidence intervals provide context for the direction and uncertainty of the group outcomes, but they do not supply a separate confidence interval or estimate for the between-group contrast.

A summary-statistic re-calculation of the primary two-arm comparison is not available because the values needed for that comparison are missing or not estimable in the posted record. Consequently, there is no recalculated primary estimate or test to set against the sponsor’s analysis. The sponsor’s reported test remains the available inferential comparison for the primary outcome; the group means can be interpreted descriptively alongside it.

The registry does not report enough detail to reproduce the sponsor’s full analysis or examine all its assumptions. No discrepancy between a sponsor analysis and a recalculation is indicated in the record. This does not mean that the analysis has been independently verified; it means only that the posted primary comparison is the result available for interpretation.

11. Multiplicity, Missing Data and Analysis Populations

The record identifies one primary outcome and several secondary outcomes. Considering multiple outcomes can increase the chance of observing an apparently notable result even when there is no underlying effect. Statistical approaches can address this issue by prespecifying a testing hierarchy or adjusting the interpretation of tests. Whether such a plan was specified or applied is not reported in the registry record. The reported secondary p-values should therefore not be read as if they were adjusted for the full family of outcomes.

Some listed secondary outcomes have no posted results. Specifically, results for respiratory-rate change and oxygen-saturation change are not reported in the registry record. The registry does not explain whether these outcomes were not collected, were collected but not posted, or were unavailable for another reason. The absence of a result should not be interpreted as a finding of no difference.

The record does not describe missing primary outcome data, reasons for missingness, or how any missing values were handled. It also does not identify whether the primary analysis followed an intention-to-treat, per-protocol, or other analysis population. The listed group sizes give the numbers associated with the posted primary summaries, but do not resolve those analysis-population questions or document completeness of follow-up.

Other analysis details that could affect interpretation are not reported, including a complete statistical analysis plan, any interim analyses, and a sample-size justification. These omissions do not invalidate the reported result, but they constrain assessment of whether the analysis followed prespecified choices and how robust the conclusions are to missing data or multiple testing. The registry record supports interpretation of the posted outcome summaries and test, not reconstruction of unreported procedures.

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 0% reporting threshold.

For each group, the registry reports zero participants with a serious adverse event among 31 at risk and zero with another adverse event among 31 at risk. These are counts in the posted record, not proof that no adverse events occurred outside the recording or reporting procedures used in the trial. The record does not describe the adverse-event collection period, definitions, or ascertainment methods.

The death values are not reported in the registry record; they should not be interpreted as zero deaths. Likewise, the posted zero counts do not establish that the treatments have identical safety profiles or exclude uncommon events. The small group sizes and the absence of further safety detail limit what can be inferred. These figures describe what the registry reports and do not support a broader safety conclusion.

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

The primary result describes short-term change in a respiratory assessment score among children enrolled in this emergency-department trial. The score combines changes in respiratory distress assessment and respiratory rate, and the registry defines a decrease as improvement. The posted group means were both negative, with a more negative mean in the normal-saline group. The registry’s two-sided test reports p = 0.01 for the primary comparison.

This finding is not, on its own, a measure of clinical importance. The registry does not report a numerical between-group estimate with a confidence interval, and the group-specific intervals cannot substitute for that missing contrast interval. The p-value indicates evidence against the null comparison under the test, but does not say how large or meaningful the difference is, or what probability there is that a particular treatment is better.

The outcome was assessed at 1 hour, so the result should not be extended to longer-term recovery or other outcomes. The trial population described in the registry is children 2-23 months with persistent distress after initial nebulized albuterol in an emergency department. The record does not establish that the result applies to different ages, clinical settings, or treatment circumstances.

Secondary results are incomplete and involve multiple outcomes, with no reported multiplicity plan. Safety reporting is also limited: zero serious and other adverse events are listed in each group, while deaths are not reported. Taken together, the record offers a short-term comparison on a defined score, but leaves important uncertainty about the size and broader relevance of the difference, the missing outcomes, and the completeness of safety reporting. It does not support a general claim that either treatment works or does not work.

14. Why This Trial Matters Statistically

This trial illustrates why direction, estimation, and testing need to be read together. RACS is defined so that a decrease signifies improvement; without that scale definition, negative mean changes could be misread. The group means show the observed direction of change, while the reported two-sided test addresses evidence of a difference. Neither piece alone provides a complete account of the contrast.

It also illustrates a common reporting limitation: group-level confidence intervals are available, but the registry does not report a confidence interval for the difference between groups. A reader can see uncertainty around each mean, but cannot directly assess the precision of the primary contrast from those intervals. The p-value does not fill that gap because it is not an estimate of effect size or a measure of precision.

The outcome is a composite of respiratory assessment and respiratory-rate change. Composite scores can capture more than one dimension, but their interpretation depends on how components are combined and what a unit change means. The registry describes the scoring increments and direction, yet does not explain the selection rationale or report evidence about clinical importance. That distinction helps keep a statistically detectable difference separate from a clinically meaningful one.

Finally, the record demonstrates why incomplete secondary and safety reporting matters. Multiple outcomes invite cautious interpretation, and unavailable results cannot be treated as null findings. Transparent reporting of analysis populations, missing data, multiplicity decisions, and between-group estimates would make the statistical evidence easier to assess.

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.

Several limitations specific to this registry record constrain interpretation. The primary outcome is reported as group means with group-specific confidence intervals, but no numerical estimate or confidence interval for the between-group contrast is posted. The sponsor’s primary test is reported, but its complete analytic details are not available, and the summary data do not permit a recalculation of the primary comparison.

The primary measurement captures change from baseline to 1 hour. The record does not provide longer-term results, so the posted primary finding is limited to that short-term assessment. The registry describes the score’s components and direction, but does not report a rationale for its selection or how a change in score relates to a clinically important difference.

Secondary reporting is incomplete: results for respiratory-rate change and oxygen-saturation change are not reported in the registry record. The record also does not state whether secondary analyses were prespecified, whether multiplicity was addressed, or how missing observations were handled. It does not identify the analysis population or provide the original sample-size justification. These gaps limit evaluation of robustness and the scope of the secondary findings.

The safety record lists zero serious and other adverse events in each group, but does not describe ascertainment, follow-up duration, or event definitions. Deaths are not reported. The record also does not specify masking roles, allocation concealment, adherence, or other implementation details. These are reporting limitations; they should not be converted into assumptions about what occurred during the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Hypertonic Saline for Acute Bronchiolitis — NCT01247064.
• Registry record last updated 2014-08-19; status last verified 2014-07.
• Results first posted 2014-08-19.
• 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.

19. Record Summary

The registry describes a completed Phase 4 randomized, quadruple-masked, parallel-group trial comparing nebulized 3% saline with nebulized 0.9% normal saline for acute bronchiolitis in children presenting to an emergency department. The brief summary specifies children 2-23 months with persistent respiratory distress after initial nebulized albuterol. Enrollment was 62, and the primary outcome summaries list 31 participants in each group.

The primary endpoint was mean RACS change from baseline to 1 hour; a decrease signifies improvement. The registry reports a two-sided t-test with p = 0.01. The group means show a more negative change in the normal-saline group, but no between-group confidence interval is reported. Secondary results are posted for some, but not all, listed outcomes. The record reports zero serious and other adverse events in each group; deaths are not reported.

The registry does not report the sample-size justification, analysis population, missing-data approach, or multiplicity plan. These omissions limit how fully the analyses and their broader implications can be assessed.