Durability of Hypertonic Saline for Enhancing Mucociliary Clearance in Cystic Fibrosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Durability of Hypertonic Saline for Enhancing Mucociliary Clearance in Cystic Fibrosis (NCT01094704), a randomized phase 1 study. The primary outcome is Change in Average Mucociliary Clearance (0-90 Minutes) at 1 and 4 Hrs Post Dose (MCC4hr - MCCbaseline; MCC1hr - MCCbaseline).

2. Clinical Question

The study's rationale is methodological as well as clinical. The registry describes mucociliary and cough clearance measurements as a biomarker used in cystic fibrosis, and says more information about the biomarker's performance could inform exploratory trial design for inhaled therapies. In that context, the question is whether this measurement can characterize persistence of an effect after treatment. It is not, by itself, a question about symptoms, lung function, exacerbations, or other clinical outcomes; those are not reported as endpoints in the registry record.

3. Trial Design

This is a completed Phase 1 randomized parallel study sponsored by the University of North Carolina, Chapel Hill. The registry reports an enrollment of 16 and lists the condition as cystic fibrosis. The study started in 2009-11, reached primary completion in 2010-05, and has status COMPLETED. These dates describe the record's study timeline; they do not establish when results were analyzed or posted.

Participants were assigned to one of two listed arms: Hypertonic Saline - 1 Hour or Hypertonic Saline - 4 Hours. Both arms name sodium chloride (7%). The arm descriptions distinguish when mucociliary clearance was measured after the dose: 1 hour post-dose in one arm and four hours post-dose in the other. The parallel design indicates that the arms are separate groups rather than repeated observations in the same participants, as described in the registry. The number randomized and the details of the allocation procedure are not reported in the registry record beyond the designation RANDOMIZED.

Masking is listed as NONE. The record therefore does not describe blinded treatment assignment or outcome assessment. It does not state whether the people measuring clearance knew the assigned measurement time, or whether other safeguards against measurement bias were used. Those details are not reported in the registry record.

The primary outcome is a continuous measure. The record labels its summary parameter as a mean and its dispersion measure as a standard deviation, with an ITT population and a timeframe of 1-4 hours post-dose. It reports 8 participants in each arm for this outcome. An analysis count of 0 is posted, and no secondary outcomes are posted. The registry does not give a protocol-level statistical analysis plan, the criteria for inclusion in the ITT analysis, or a sample-size justification.

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

Analysis population for the primary outcome, as defined in the registry: ITT

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 Change in Average Mucociliary Clearance (0-90 Minutes) at 1 and 4 Hrs Post Dose (MCC4hr - MCCbaseline; MCC1hr - MCCbaseline), measured over 1-4 hours post-dose.

The primary endpoint is change in average mucociliary clearance from baseline. Its title specifies an average measured over 0-90 minutes and describes change at 1 and 4 hours post-dose as the post-dose measurement minus baseline. The reported unit is Absolute % change. The registry describes the endpoint as a way to assess the duration of hypertonic saline's action, using mucociliary clearance and cough clearance measurements, although the posted primary outcome title names average mucociliary clearance.

Mucociliary clearance concerns the movement of material out of the airways through mucus and ciliary activity. The registry's rationale identifies mucociliary and cough clearance measurements as a biomarker in cystic fibrosis. As a biomarker, the endpoint can provide a physiological measurement relevant to airway clearance and may help characterize how a response changes over time after dosing. General statistical context: a biomarker can be informative about a biological process without directly measuring how a participant feels, functions, or experiences a clinical event.

The outcome is continuous, so the registry reports a mean and standard deviation for each group. The mean describes the group's average measured change, while the standard deviation describes the spread of participant measurements around that average. These summaries do not show the full distribution or establish whether a difference between groups is statistically distinguishable from chance. Confidence intervals, participant-level values, and an inferential comparison are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, parallel study with no masking. Randomization is a method for assigning participants to groups by chance, with the general aim of reducing systematic differences in baseline characteristics. It does not guarantee that groups will be balanced, especially in a small study. The record does not describe the allocation sequence, concealment procedures, or any stratification. Those methodological details are not reported in the registry record.

What do the mean and standard deviation describe?

The primary endpoint is continuous and is summarized with a mean and standard deviation. A mean is the arithmetic average of observed measurements. A standard deviation describes how dispersed observations are around the mean: a larger value generally indicates more variability among participants. Here, the means are 5.9 and 6.7, and the standard deviations are 8.9 and 14.4, respectively. Each group has 8 participants. These summaries are not sufficient to reconstruct the participant-level data, determine the shape of the outcome distribution, or identify whether a small number of observations strongly influenced the results.

General statistical context: when data are highly variable, a mean can be estimated less precisely from a given sample than when observations are tightly clustered. The standard deviation is not the standard error and is not a confidence interval. A confidence interval would express uncertainty around an estimated quantity, such as a group mean or a between-group contrast, under a specified method. No confidence intervals are reported in the registry record, so the precision of the means and of any contrast cannot be read directly from the posted results.

What can a between-group analysis establish?

A comparative analysis would ordinarily estimate a contrast between the groups and quantify its uncertainty, potentially using a confidence interval and a test of a stated null hypothesis. The registry posts no such estimate or test. It lists 0 analyses and notes that values are missing or not estimable for a two-arm comparison of the continuous endpoint. The descriptive means alone do not supply the uncertainty needed for a formal conclusion about a group difference. No p-value is reported in the registry record.

The groups differ in the timing of the clearance measurement after the named intervention. A comparison of their group summaries is not the same as a repeated-measures analysis of the same participants at both times. The arm descriptions do not indicate that the same participants contributed measurements at both timepoints. The registry's parallel design and separate arm counts describe separate groups. Further detail about the exact outcome calculation, baseline handling, or statistical model is not reported in the registry record.

How should sample-size illustrations be read?

The registry's stated planning assumptions describe illustrative sample-size calculations based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The planning effect is described as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence about whether the study's results are statistically significant. The actual design rationale, including any sample-size justification used when the trial was planned, is not reported in the registry record. Numerical planning results and the specific effect fractions are not reported in the registry record available for these results.

General statistical context: sample-size calculations depend on assumptions about the effect to detect, outcome variability, significance level, allocation, and analysis method. Changing an assumption can change the resulting planning estimate. An estimate based on an observed effect is especially dependent on the observed data and should not be mistaken for a prospective design justification. The posted planning assumptions do not replace a protocol or statistical analysis plan.

What is known about multiplicity and missing observations?

The registry posts one primary outcome and no secondary outcomes. It does not report a multiplicity adjustment or state how multiple comparisons were handled. With no inferential analysis posted, there are no reported analysis-specific multiplicity procedures to evaluate. The record identifies the primary population as ITT, but it does not explain how participants were handled if an endpoint measurement was absent, nor does it describe imputation, exclusions, or sensitivity analyses. Missing-data methods are not reported in the registry record.

General statistical context: missing outcomes can affect interpretation if the chance of being measured is related to participants' outcomes or characteristics. An ITT label indicates an intended analysis population but, on its own, does not disclose how missing measurements were treated. The posted record does not provide enough information to evaluate that issue.

How should safety counts be interpreted?

The adverse-event summaries list 8 participants at risk in each group and 0 participants affected by a serious adverse event in each group. They also list 0 participants affected by other adverse events in each group. These are posted counts, not a statistical comparison. The registry does not provide event descriptions for these categories, and deaths are not reported in the registry record. General statistical context: zero observed events in a small group does not establish that the underlying event risk is zero.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Hypertonic Saline - 1 Hour", "Hypertonic Saline - 4 Hours")
n   <- c(8, 8)
m   <- c(5.9, 6.7)
sp  <- c(8.9, 14.4)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Hypertonic Saline - 1 Hour  8  5.900  8.900  -1.541  13.341
CARM  Hypertonic Saline - 4 Hours  8  6.700  14.400  -5.339  18.739

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary outcome and lists no secondary outcomes. It does not report a multiplicity strategy, such as an adjustment to account for testing multiple outcomes or contrasts. Since no inferential analyses are posted, it is not possible to assess how multiplicity would have been handled in the sponsor's analysis. Any formal analysis plan or prespecified hierarchy of tests is not reported in the registry record.

The primary outcome population is labeled ITT, and the reported outcome sample size is 8 in each arm. The registry does not explain whether these are all randomized participants, how the ITT population was defined, or whether any participants were excluded from the endpoint analysis. It does not give a participant flow, missing-measurement counts, reasons for missingness, or methods for handling missing observations. Those details are not reported in the registry record.

General statistical context: an ITT approach typically seeks to preserve the randomized comparison by analyzing participants according to their assigned groups. The label alone does not reveal how incomplete outcomes are treated. Complete-case analysis, imputation, and sensitivity analyses make different assumptions about unobserved measurements; the registry does not state whether any of these methods were used.

The analysis count is 0, and a two-arm comparison of the continuous endpoint is marked as not estimable or missing. As a result, the posted record does not offer adjusted or unadjusted inferential results that could be examined for missing-data sensitivity or multiplicity handling. The protocol's missing-data plan and final analysis methods are not reported in the registry record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The adverse-event summaries report 8 participants at risk in each arm. For serious adverse events, 0 participants are listed as affected in the Hypertonic Saline - 1 Hour group and 0 in the Hypertonic Saline - 4 Hours group. For other adverse events, the posted affected counts are also 0 in each group. These counts describe what the registry reports for the listed groups; they are not evidence from a statistical comparison of safety between measurement times.

The registry does not list serious adverse-event terms. Death counts are not reported in the registry record. It also does not provide event-level descriptions, timing, severity categories beyond the serious-event classification, or further information about ascertainment. The posted zero counts should therefore be read narrowly as zero participants recorded as affected in those summaries, not as proof that no adverse event occurred or that the underlying risk is absent.

General statistical context: with small groups, observing no events does not precisely identify the frequency of rare events. These safety figures do not establish comparative safety, and the registry record does not provide an inferential safety analysis. The study's listed outcome focuses on mucociliary clearance rather than a detailed safety evaluation.

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

The results provide descriptive information about average change in mucociliary clearance after sodium chloride (7%) at the measurement times specified by the study. The 1-hour group has a reported mean change of 5.9 and standard deviation of 8.9 among 8 participants. The 4-hour group has a reported mean change of 6.7 and standard deviation of 14.4 among 8 participants. The registry reports the outcome as Absolute % change from baseline.

These summaries do not establish whether the average changes differ beyond what might be expected from sampling variability. The record posts no confidence interval, p-value, or model-based contrast, and it marks a two-arm comparison as missing or not estimable. Therefore, the numerical summaries should not be treated as a formal test of a difference, a demonstration of equivalence, or a precise estimate of how the response changes over time.

The measured endpoint is a biomarker of airway clearance, identified in the registry rationale as relevant to cystic fibrosis research and exploratory trial design. General statistical context: a biomarker can help characterize a biological response but does not automatically establish an effect on outcomes that matter directly to participants. The registry does not report clinical outcomes such as symptoms, lung function, or exacerbations as primary or secondary results.

The study's stated objective is to investigate whether mucociliary and cough clearance measurements can characterize durability of action. The posted outcome summaries address average clearance change at different post-dose times in separate arms. They do not describe individual trajectories, confirm a mechanism, or establish how broadly the findings apply beyond the study participants. No demographic or clinical characteristics are reported in the registry record to support assessment of generalizability.

In short, the registry reports a small randomized study with descriptive endpoint and adverse-event counts, but no posted comparative analysis. The results can be read as summaries of the measured groups, with substantial variability indicated by the standard deviations. The record does not support a definitive statistical conclusion about a between-group effect or a broad conclusion about clinical outcomes.

14. Why This Trial Matters Statistically

This study illustrates a statistical challenge common to early clinical research: a biological measurement may be intended to serve as a biomarker for later trials, but its behavior and variability need to be understood before it can reliably guide design decisions. The registry explicitly motivates the work by noting that more knowledge of mucociliary and cough clearance measurements could inform exploratory trial design for inhaled cystic fibrosis therapies.

The endpoint is continuous, and the posted summaries include both group means and standard deviations. That combination matters because an average response alone does not describe how consistently participants respond. The standard deviations, particularly alongside the small group sizes of 8 participants each, signal that the observed measurements vary appreciably. General statistical context: variability affects the precision of estimates and the number of observations that may be needed to detect a specified effect in future studies.

The registry describes planning illustrations based on the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations can help demonstrate how planning assumptions relate to future study size, but they are not evidence that the current study had adequate power. The actual sample-size justification is not reported in the registry record, and no numerical planning estimates are reported in the record used for this interpretation.

There is also a useful distinction between an endpoint's scientific rationale and the evidence posted for it. The rationale proposes that clearance measurements may help assess durability. The registry reports group summaries at the specified times but no comparative analysis or precision interval. This makes transparent reporting of the analysis plan, missing-data handling, and uncertainty especially important for judging the biomarker's performance.

The record therefore highlights both the potential role of a physiological measure in early research and the limits of descriptive results from a small study. It offers a basis for understanding what was measured and how results were summarized, while leaving the strength and precision of a direct comparison unresolved.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for interpretation is that the registry posts descriptive summaries but no inferential comparison. The analysis count is 0, and a two-arm comparison of the continuous endpoint is identified as missing or not estimable. No confidence interval or p-value is reported. Consequently, the precision of a between-group contrast cannot be assessed from the registry record.

The sample is small, with 8 participants reported in each arm. The standard deviations are large relative to the means, especially in the 4-hour group, indicating considerable dispersion in the recorded measurements. Without participant-level data, the distributions, possible influential observations, and reasons for the variability cannot be examined. The record does not report baseline characteristics that would show how the groups compared before measurement.

The design compares separate parallel groups measured at different times after the same named intervention. It does not report repeated measurements in the same individuals at both times. The results therefore do not directly reveal within-person change from the earlier to later measurement. Details about the allocation process, measurement procedures, assay reliability, and handling of baseline values are not reported in the registry record.

Masking is listed as NONE. The record does not explain whether outcome assessors were masked or what steps were taken to reduce measurement bias. It also does not describe adherence, protocol deviations, or participant flow. Although the primary population is labeled ITT, the method for handling missing endpoint data is not reported.

Finally, only one primary outcome is posted, with no secondary outcomes and no detailed clinical outcomes. Adverse-event summaries contain zero affected participants in the listed categories, but deaths are not reported and event-level details are absent. These limitations mean the record gives a narrow view of the measured biomarker and safety summaries, rather than a comprehensive assessment of clinical effects or harms.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Durability of Hypertonic Saline for Enhancing Mucociliary Clearance in Cystic Fibrosis — NCT01094704.
• Registry record last updated 2012-08-21; status last verified 2012-08.
• Results first posted 2012-08-21.
• 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 randomized Phase 1 parallel study of hypertonic saline in cystic fibrosis, sponsored by the University of North Carolina, Chapel Hill. Enrollment is 16; the study began in 2009-11 and reached primary completion in 2010-05. Masking is listed as NONE.

The primary outcome is change in average mucociliary clearance over 0-90 minutes, measured at 1 and 4 hours post-dose and reported as an Absolute % change. The record lists 8 participants per arm. The reported mean and standard deviation are 5.9 and 8.9 for the 1-hour group, and 6.7 and 14.4 for the 4-hour group. No inferential comparison is posted, and no secondary outcomes are listed.

Serious and other adverse-event summaries each list 0 affected participants per group. Death counts and further analysis details are not reported in the registry record.