This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Assessment of Cough Reflex in Lung Transplant Recipients (NCT00584077), a registered phase not stated study. The primary outcome is Number of Coughs.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00584077 |
| Phase | Phase not stated |
| Condition | Complication of Transplanted Lung |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 15 |
| Arms in the primary outcome | n/a |
| Lead sponsor | The University of Texas Medical Branch, Galveston |
| Results posted | Yes |
2. Clinical Question
Population
Stable lung transplant recipients at the University of Texas Medical Branch, Galveston. The record lists 15 enrolled participants and describes recipients of single or double lung transplants or heart-lung transplants.
Intervention
During bronchoscopy, participants received mechanical stimulation with biopsy forceps and chemical stimulation with 5% dextrose solution on the airway mucosa. The record describes assessment at three to four separate areas of the transplanted airways.
Comparator
The study summary says cough recordings would be compared with recordings from non-transplant patients. However, the registry lists a single study arm, and does not report details about the non-transplant recordings or their participants.
Primary question
How many coughs are elicited by mechanical or chemical airway stimulation, including at locations in the native airway and transplanted airway? The primary measure is the number of coughs recorded over 15-20 minutes.
The clinical question concerns the presence and strength of the cough reflex in the lower airway after lung transplantation. The registry describes recording cough-related surface electrical activity by placing external electrodes to monitor abdominal muscle movement during a cough. The primary outcome, however, is specified as the number of coughs elicited by the airway stimuli.
The assessment is described at the main carina, proximal to the airway anastomosis in the native airway, and distal to the anastomosis in the allograft airway. These locations distinguish responses in the recipient’s airway from responses in the transplanted airway. The record describes both mechanical stimulation using biopsy forceps and chemical stimulation using D5W, meaning 5% dextrose solution.
The registry does not report numerical cough counts, means, standard deviations, or results for the comparison with non-transplant recordings. It therefore does not establish from the recorded results how frequently cough occurred, whether responses differed by airway location or stimulus, or how the transplant-recipient observations compared with those recordings.
3. Trial Design
The registry identifies this as a completed study with 15 participants enrolled. Its listed arm is “Stable lung transplant recipients.” The arm description says all enrolled participants received the same procedures: bronchoscopy with administration of mechanical and chemical irritants to the airway mucosa. The record does not describe randomized allocation or a parallel control arm.
The study summary describes participants who had a single or double lung transplant or a heart-lung transplant at the University of Texas Medical Branch. It states that the cough reflex would be assessed at the bronchoscopy performed one year after transplantation. The registry lists the primary outcome timeframe as 15-20 minutes. It also describes testing three to four separate areas of transplanted airways and assessing sites in the native airway and allograft airway.
The procedures involved placement of biopsy forceps on the airway mucosa and instillation of 3 to 5 ml of 5% dextrose. Cough activity was to be recorded using external electrodes that monitored abdominal muscle movement. The study summary says those recordings would be compared with recordings of coughs from non-transplant patients. The registry record does not report the design, recruitment, characteristics, or measurements of that comparison group, and does not list it as a study arm.
The study started in 2000-04 and had primary completion in 2006-10. The sponsor is The University of Texas Medical Branch, Galveston. The registry lists two outcome measures and two analyses, but does not report their numerical results or identify the analysis methods in detail. The record also does not report a statistical analysis plan, sample-size justification, or the procedures used to select participants.
A planning illustration associated with the record uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It is explicitly a planning calculation based on a fraction of an observed effect, not a description of the study’s actual single-arm procedures or an observed estimate of power. The record does not report the observed effect needed to interpret such planning values.
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
| Stage | Lung Transplant Recipients With Stable Lung Function |
|---|---|
| STARTED | 15 |
| COMPLETED | 15 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Lung Transplant Recipients With Stable Lung Function |
|---|---|---|
| Participants analysed | 15 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 15 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous: Age | years | 49 (SD 8) |
| Sex: Female, Male: Female | Participants | 6 |
| Sex: Female, Male: Male | Participants | 9 |
| Region of Enrollment: United States | participants | 15 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Coughs, measured over 15-20 minutes.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Coughs |
| Endpoint classification | Continuous Endpoint |
The primary outcome is the number of coughs elicited by mechanical or chemical stimulation of the airway mucosa. It is defined as a mean, with standard deviation as the measure of dispersion, and a timeframe of 15-20 minutes. The registry describes stimulation with biopsy forceps or instillation of dextrose solution, and identifies sites at the main carina, in the native airway proximal to the anastomosis, and in the allograft airway distal to the anastomosis.
Cough count is a direct count of observable responses to the procedures described. In this study, counting coughs offers a way to characterize whether stimulation is followed by a cough response and how many coughs are recorded during the specified observation period. The surface electrical recording is described as the means of monitoring abdominal muscle movement during a cough; the primary endpoint itself is the number of coughs.
Interpreting a mean requires knowing the values contributing to it and the number of participants and observations included. The standard deviation describes variability among the measurements, but does not by itself show how precisely the mean is estimated. The registry does not report the cough-count mean, standard deviation, or numerical results by stimulus or airway location. It therefore does not permit assessment of the observed response magnitude or its precision.
The secondary outcome is described as assessing the presence and strength of the cough reflex in the lower airway for up to one year. Its numerical results and detailed operational definition are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record establishes the study’s aim and procedures, but it does not provide the primary outcome values needed to quantify the cough response. Although the primary outcome is defined as the mean number of coughs, the mean, standard deviation, and participant-level or group-level results are not reported in the registry record. No effect estimate or confidence interval is reported. Consequently, the registry record does not allow readers to judge the size or precision of the observed cough counts.
The study summary describes testing mechanical and chemical stimuli at several airway locations. The registry does not report numerical results separately by stimulus or location. It is therefore not possible to determine from the record whether responses varied according to the procedure used or whether findings differed between the native airway and allograft airway. Such comparisons should not be inferred from the endpoint description alone.
The summary also mentions comparison with recordings from non-transplant patients. The registry lists only one arm of stable lung transplant recipients and does not describe the non-transplant group’s size, selection, measurement procedures, or results. Without those details and the corresponding outcome values, the record does not support a quantitative comparison between transplant recipients and non-transplant patients.
The enrollment of 15 participants sets the scale of the study, but the record does not report how many participants contributed data to each endpoint or analysis. The stated enrollment should not be assumed to equal the analysis population for every outcome. Missing measurements, exclusions, and the handling of incomplete recordings are not reported in the registry record.
The status is completed, but completion does not itself indicate what the measured responses were. Nor does the number of analyses listed establish which statistical methods were applied or whether the results were adjusted for multiple comparisons. Those details are not reported in the registry record. No p-values or other inferential results are reported in the available outcome descriptions.
General interpretation: an estimate describes the observed data, while its uncertainty reflects how much the estimate might vary under repeated sampling or other sources of uncertainty. A confidence interval, if reported, would help describe precision; none is reported for the primary outcome. Statistical significance, if it had been assessed, would not alone establish the clinical importance of an effect. Here, without numerical results, neither magnitude nor inferential certainty can be evaluated from the registry entry.
The sample-size calculations described as planning illustrations use an assumed fraction of an observed effect and specified two-arm planning conditions. They are not the study’s actual design, and they are not observed power. The registry record does not report the observed effect or a trial-specific sample-size justification, so those illustrations cannot fill the gap in the outcome reporting.
9. Statistical Methods Explained
The registry characterizes the primary endpoint as a continuous measure summarized by a mean and standard deviation. The underlying observation is a count of coughs. A mean gives the average count across whatever observations are included in the analysis, while the standard deviation describes the spread of those observations around the mean. These summaries answer different questions: the mean describes the center of the observed counts, and the standard deviation describes their variability.
The endpoint description identifies several stimulation procedures and airway locations. If measurements are taken repeatedly from a participant, those measurements may be related rather than independent, because they come from the same person. General statistical principle: analyses of repeated measurements need to account for that dependence when estimating uncertainty. The registry record does not report whether repeated measurements were analyzed separately, combined, or handled with a model that accounts for within-participant correlation.
What does a confidence interval convey?
General statistical explanation: a confidence interval gives a range of values compatible with the observed data under the assumptions of the statistical method. Its width is informative about precision: a wider interval reflects greater uncertainty than a narrower interval. A confidence interval is not a guarantee that the true value lies within the interval, and it does not by itself describe whether a difference is clinically important. The registry record does not report a confidence interval for the primary outcome.
For a comparison of means, an estimate of the difference and its confidence interval would usually convey both the direction and precision of the comparison. In this study, the registry mentions comparison with recordings from non-transplant patients but does not report those data, an estimated difference, or a confidence interval. The existence of a planned or described comparison does not establish that the groups were analyzed as a formal comparative study.
Why does the design matter?
The listed study arm consists of stable lung transplant recipients who all receive the same procedures. The record does not identify randomized allocation or a parallel control arm. General statistical explanation: random allocation, when used, can help make groups comparable in expectation, while an observational comparison may be affected by differences between the groups. Since the non-transplant recordings are not described in enough detail, the registry does not establish how comparable those observations are to the transplant-recipient measurements.
The primary endpoint is a count, but the record specifies a mean and standard deviation. General statistical explanation: count data can have distributions that differ from the symmetric patterns assumed by some standard methods. If counts are highly variable or their variability exceeds what a chosen model expects, over-dispersion can make standard errors too small and confidence intervals too narrow unless the analysis accounts for it. The registry does not report the count distributions or the methods used to assess or address over-dispersion. This is a general consideration, not a claim that over-dispersion occurred in this study.
What can be said about planning calculations?
The record describes a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the effect to detect is a stated fraction of the observed effect. These are assumptions for illustrating sample-size requirements, not evidence that the study used two arms or equal allocation. The actual listed study arm contains stable lung transplant recipients, and the registry does not report a randomized two-arm design.
General statistical explanation: a sample-size calculation depends on the outcome variability, the effect size to be detected, the significance threshold, the desired power, and the design assumptions. Changing an assumed effect size changes the sample size required under those assumptions. These calculations are planning tools; they do not measure the probability that a completed study’s finding is correct, and they are not observed power. The registry record does not report the study’s own sample-size justification, the observed effect used in the illustration, or a detailed protocol specifying a target power.
What is not reported about the analyses?
The record lists two analyses, but does not name their methods or present numerical analysis results. It does not report whether estimates were adjusted, which observations were included, how repeated airway-site measurements were treated, or whether assumptions were checked. The stated endpoint summary of mean and standard deviation does not identify the inferential method used to analyze the data.
General statistical explanation: an analysis plan ordinarily specifies the outcome, comparison, statistical model, handling of missing observations, and criteria for interpreting results. Prespecification can reduce the risk that analysis choices are made in response to observed results. The registry record does not report a statistical analysis plan or enough detail to assess whether the analyses followed a prespecified approach. That absence should be read as unreported information, not evidence that a particular method was or was not used.
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.
| Arm | Participants | Mean | Standard deviation | 95% CI for the mean |
|---|---|---|---|---|
| Lung Transplant Recipients With Stable Lung Functi | 15 | 7.300 | 5.200 | 4.420 to 10.180 |
R code and output
arm <- c("Lung Transplant Recipients With Stable Lung Functi")
n <- c(15)
m <- c(7.3)
sp <- c(5.2)
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 Lung Transplant Recipients With Stable Lung Functi 15 7.300 5.200 4.420 10.18011. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures and two analyses. It does not report the full analysis plan, identify all comparisons or tests, or explain whether any adjustment was made for multiple testing. Since the study description involves different stimuli and airway locations, a reader might want to know whether results were evaluated separately for each. The registry record does not say how many such comparisons were made or how multiplicity was addressed.
General statistical explanation: when many hypotheses are tested, the chance of at least one apparently notable result can increase. Methods for controlling multiplicity can address that concern, but the appropriate approach depends on the objectives and analysis plan. No particular multiplicity procedure is reported in the registry record, so it should not be assumed that adjustment was or was not performed.
The record lists 15 participants enrolled. It does not report the number contributing data to each outcome or analysis, the amount of missing data, reasons for missingness, or how incomplete recordings were handled. It also does not state whether every participant completed the bronchoscopy procedures or whether any observations were excluded.
The analysis population is not described beyond the enrollment figure and the arm description. The registry record does not report whether analyses included all enrolled participants, only participants with usable measurements, or another defined group. General statistical explanation: these distinctions matter because the observations included in an analysis determine which participants and measurements the estimate represents. With no analysis-population definition or missing-data account, the completeness and representativeness of the reported endpoint results cannot be evaluated.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Lung Transplant Recipients With Stable Lung Function | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Lung Transplant Recipients With Stable Lung Function | 0 of 15 |
The registry lists 15 participants at risk for serious adverse events and zero participants affected. It also lists 15 participants at risk for other adverse events and zero participants affected. No serious adverse event terms are listed. These are the adverse-event figures recorded for the study.
These counts describe reported affected participants, not the number of coughs or the primary efficacy outcome. The record does not report further detail about adverse-event definitions, collection methods, timing, severity grading, or follow-up. Deaths are not reported in the registry record.
General statistical explanation: a count of zero reported events does not demonstrate that the true risk is zero. The interpretation depends on how events were defined, how completely they were monitored, and the amount of observation. Here, the registry provides the at-risk counts and affected counts, but does not provide the additional monitoring details needed for a fuller safety assessment. The figures should therefore be read as registry-reported counts, not as proof that no adverse effects occurred.
13. What the Result Does, and Does Not, Mean
The registry record describes a completed study designed to assess cough reflex responses in stable lung transplant recipients. It specifies airway stimulation with biopsy forceps and dextrose solution, recording of cough-related abdominal muscle activity, and a primary endpoint defined as the number of coughs over 15-20 minutes. It also identifies airway sites in the native and transplanted airways.
The record does not report the numerical primary outcome results. It provides no mean cough count, standard deviation, estimate of a comparison, confidence interval, or p-value. As a result, it does not show the magnitude or precision of the observed cough response. It also does not report results by airway site or stimulus, so no conclusion about differences between those conditions can be drawn from the registry entry.
The study summary mentions comparison with cough recordings from non-transplant patients, but the registry does not describe that group or provide its results. The listed study arm contains stable transplant recipients and the record does not report a randomized comparison. Therefore, the registry does not support a quantitative conclusion about how transplant-recipient measurements compare with non-transplant measurements.
The completed status and enrollment of 15 describe the record’s study status and scale; they do not substitute for outcome data. Similarly, the adverse-event figures report zero affected participants in the listed serious and other adverse-event categories, but do not provide details about event definitions or monitoring. Those counts should not be interpreted as proof of zero risk.
General statistical explanation: a study’s result is best understood by considering the estimate, its uncertainty, the analysis population, and the design that produced the data. In this record, several of those elements are not reported. The appropriate interpretation is therefore limited to the described aim, procedures, endpoint definition, enrollment, and registry-reported safety counts. The record does not establish a treatment effect or support a claim that a treatment works or does not work.
14. Why This Trial Matters Statistically
This study raises a useful statistical issue: a clearly described endpoint is not the same as a reported result. The registry specifies a count of coughs, a summary format using the mean and standard deviation, a timeframe, and the airway locations and stimuli of interest. Those details help define what was intended to be measured. Without the numerical outcome data, however, readers cannot evaluate the observed response or its precision.
The design description also highlights the importance of distinguishing a study procedure from a comparison. All participants in the listed arm receive the same bronchoscopy procedures, while the summary mentions recordings from non-transplant patients. Because the non-transplant group is not described as a registry arm and its measurements are not reported, it cannot be treated as a documented like-for-like control group.
The outcome involves stimulation at multiple locations and with more than one method. General statistical consideration: when measurements are obtained at multiple sites or under multiple conditions, clear reporting of the analysis structure is important. Readers need to know whether measurements are independent, how within-participant correlation is handled, and whether multiple comparisons were considered. Those details are not reported in the registry record.
The entry also shows why planning illustrations must be kept distinct from study results. The stated calculation assumptions describe a hypothetical two-arm planning setup, while the listed study arm is a single group of stable lung transplant recipients. Planning calculations cannot replace a trial-specific justification or supply missing outcome estimates, and they are not observed power.
For clinical researchers and biostatisticians, the record is a reminder to report outcome estimates, uncertainty, analysis populations, missing-data handling, and the role of each comparison. Those elements are needed to move from a description of methods to an interpretable statistical result.
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 principal limitation for interpreting the record is that the numerical primary outcome results are not reported. The mean number of coughs, standard deviation, and results by airway location or stimulation method are absent. No confidence intervals or inferential statistics are reported, so the size and precision of any observed response cannot be assessed.
The registry lists 15 enrolled participants but does not report the number included in each analysis. It does not describe missing measurements, exclusions, protocol deviations, or the handling of incomplete recordings. The resulting analysis populations and their relationship to enrollment are therefore not reported in the registry record.
The summary mentions recordings from non-transplant patients, but the registry does not report their number, characteristics, selection, measurement procedures, or outcomes. The study lists a single arm of stable lung transplant recipients. This leaves the intended comparison insufficiently described for assessing group comparability or interpreting a difference.
The endpoint description includes several airway locations and both mechanical and chemical stimulation, but no numerical results or detailed analysis methods are reported for these conditions. The record does not explain how repeated measurements from the same participant were handled, whether comparisons were prespecified, or whether multiplicity was addressed.
The record does not report a statistical analysis plan, trial-specific sample-size justification, or detailed methods for safety monitoring. The planning illustration is based on a two-arm setup and an observed effect, but the effect and its relation to the study analyses are not reported. These reporting gaps limit statistical interpretation; they do not establish that the unreported procedures or analyses were not performed.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Assessment of Cough Reflex in Lung Transplant Recipients — NCT00584077.
- Registry record last updated 2018-11-02; status last verified 2018-02.
- Results first posted 2015-09-25.
- 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.
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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
19. Record Summary
The record describes a completed study of cough reflex assessment in stable lung transplant recipients, sponsored by The University of Texas Medical Branch, Galveston. It lists 15 enrolled participants and one arm, in which all participants receive bronchoscopy with mechanical and chemical airway stimulation. The study summary describes recipients of single or double lung transplants or heart-lung transplants and assessment at the bronchoscopy one year after transplantation.
The primary outcome is the number of coughs elicited by biopsy forceps or dextrose solution, summarized as a mean with standard deviation over 15-20 minutes. The record describes assessment at the main carina and in native and allograft airway locations. It also mentions comparison with cough recordings from non-transplant patients, without reporting details or results for that group.
The study started in 2000-04 and had primary completion in 2006-10. Numerical primary outcome results, analysis methods, missing-data details, and statistical-plan information are not reported in the registry record. The safety listing reports zero affected participants among 15 at risk in both the serious and other adverse-event categories; deaths are not reported in the registry record.