Lansoprazole to Treat Children With Asthma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lansoprazole to Treat Children With Asthma (NCT00442013), a randomized phase 4 study. The primary outcome is Change in Juniper Asthma Control Score (ACS).

2. Clinical Question

3. Trial Design

The registry describes a randomized, triple-masked, parallel-group Phase 4 study sponsored by Johns Hopkins University. Enrollment was 306. The record lists the study as completed, with a start date of 2007-03 and primary completion in 2011-04. These design details identify the structure of the trial, but they do not by themselves establish how participants were recruited or how randomization and masking were implemented.

Participants were assigned to lansoprazole or matching placebo. Both descriptions specify daily treatment for 6 months. The active-treatment description says doses depended on body weight at randomization and gives a partial dosing description. The placebo description likewise describes weight-dependent matching. Full dosing instructions are not reported in the registry record. The record does not state the randomization ratio or describe allocation concealment.

The primary outcome was change in Juniper Asthma Control Score, measured at Weeks 0, 4, 8, 12, and 24. The registry describes the result as an average of change from baseline to all follow-up points. It does not explain whether the repeated measurements were analyzed jointly, how missing assessments were handled, or what population was included in the primary analysis.

Five secondary outcomes are listed: asthma-specific quality of life, pre-bronchodilator forced expiratory volume in one second, rate of episodes of poor asthma control, Asthma Symptom Utility Index, and airway reactivity assessed by methacholine PC20. Results for these secondary measures are not reported in the registry record. The registry record also does not report the protocol, sample-size justification, interim analyses, or detailed statistical plan, so those elements cannot be inferred from the design description.

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 Change in Juniper Asthma Control Score (ACS), measured over Measured at Weeks 0, 4, 8, 12, 24.

The primary endpoint is change in Juniper Asthma Control Score, a questionnaire-based measure of asthma control. The registry says the score ranges from 0 to 6 and that lower scores indicate better asthma control. Scores above 1.5 are described as indicating poor asthma control. The questionnaire has 6 questions related to asthma control and forced expiratory volume. The reported outcome is an average of change from baseline to the follow-up points at Weeks 0, 4, 8, 12, and 24.

Using a continuous score preserves information about the amount of change rather than reducing each participant to a simple improved/not-improved category. A mean summarizes the average change across participants, while the between-group comparison addresses whether average change differs between treatment groups. The confidence interval gives a range of values compatible with the model and data under its assumptions, and helps convey precision as well as the estimated difference.

The score’s direction is clear for the score itself: lower values indicate better control. However, the registry does not state the arithmetic convention for change from baseline, or the sign orientation of the reported net difference. Therefore, the positive reported difference should not be translated into a direction of clinical benefit from the registry entry alone. Interpretation also depends on the timing and handling of repeated measurements, details that are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: each participant has a score, and the registry reports group means and a mean difference. For a continuous outcome, a mean summarizes the center of the observed values. It can be informative, but it does not describe the full distribution; participants may have had changes that varied substantially around the mean. The registry does not post a measure of spread for the arm summaries.

What does the confidence interval communicate?

A confidence interval describes the precision of an estimate under the statistical model used to construct it. A narrower interval indicates greater precision, while a wider interval leaves more uncertainty about the underlying difference. The sponsor’s reported 95% confidence interval for the net mean difference is 0.0 to 0.3. This interval should be read alongside the point estimate of 0.2 rather than as a set of values all equally likely. Its endpoints are rounded in the registry, so the displayed 0.0 does not reveal the exact unrounded endpoint.

Confidence intervals also depend on assumptions and the analysis population. The registry names linear regression but does not report the model specification, covariates, diagnostics, or handling of incomplete observations. A confidence interval cannot correct for bias caused by inappropriate analysis choices or missing data. It quantifies uncertainty within the chosen analysis, not every source of uncertainty in the study.

How should the p-value be read?

The reported p-value is 0.12. In general, a p-value describes how compatible the observed data are with a specified null model, given the statistical assumptions. It is not a measure of the probability that the result is due to chance, and it does not tell whether an effect is clinically important. The registry does not report the decision threshold or a complete testing plan, so the p-value should be interpreted as a reported statistic rather than as a complete account of the study’s inferential framework.

The p-value and confidence interval are related summaries of the same comparison, but they emphasize different aspects. The interval shows the estimate’s uncertainty on the scale of the outcome; the p-value assesses compatibility with a null value under a test. Rounded interval endpoints can make a null boundary appear to be exactly included or excluded when the unrounded result is not visible. The registry’s rounded interval and p-value should therefore be read as reported rather than used to reverse-engineer unreported digits.

Why may the arm means differ from the regression estimate?

The group means describe the observed change within each arm. The regression result is the sponsor’s inferential comparison, reported as a net mean difference. These quantities can differ because the model may account for participant-level information in a way that is not captured by comparing the displayed arm means alone. The registry does not identify covariates or other model details. The regression result should therefore be attributed to the sponsor’s stated linear-regression analysis; its exact adjustment cannot be reconstructed from the registry entry.

The trial also assessed the outcome at repeated follow-up points. The record says the primary value represents an average of change from baseline to all follow-up points. It does not explain whether this average was calculated first for each participant, whether the repeated observations were modeled jointly, or how observations at some but not all visits contributed. Those choices can affect the estimate and its standard error. They are not reported in the registry record.

What do planning illustrations mean?

Sample-size planning uses assumptions about the effect to be detected, the variability of the outcome, the significance level, allocation, and the desired power. A planning illustration based on an observed effect is a hypothetical design calculation, not evidence about the trial’s probability of detecting an effect after it was completed. The registry describes planning assumptions of a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of the observed effect. Numeric planning results are not reported in the registry record. These illustrations should not be confused with the trial’s original enrollment plan or with observed power. The trial’s own sample-size justification is not reported in the registry record.

Continuous-outcome planning also depends on variability. The registry does not report an arm-level standard deviation for the primary outcome, and no planning values can be reconstructed from the listed confidence intervals without making assumptions. Any design calculation should therefore be treated as conditional on its stated assumptions, not as a new observed result.

What does over-dispersion mean in general?

Over-dispersion is a general concern when the variation in data is greater than a statistical model expects. It is especially relevant for count outcomes, where a simple model may understate variability if observations are more heterogeneous than assumed. The primary endpoint in this trial is a continuous score, and the registry identifies linear regression for the primary comparison. The registry does not provide diagnostics or information that would establish whether over-dispersion was considered for the secondary rate outcome. It would be inappropriate to assert that it was present or absent.

These methods explain how to read the posted estimate, but the registry’s incomplete analysis description limits independent evaluation of model adequacy. The reported result remains the sponsor’s analysis; details beyond the stated method are not reported in the registry record.

10. Analyses Reported by the Sponsor

The sponsor’s reported primary comparison uses linear regression and gives a net mean difference of 0.2, with a 95% confidence interval from 0.0 to 0.3 and p = 0.12. The arm summaries separately report mean changes of 1.1 for lansoprazole and 1.0 for placebo. These summaries are not a substitute for the regression result, and subtracting displayed arm means would not reproduce the model-based comparison reliably, particularly because the values are rounded and the model details are not reported.

No separate recalculated estimate is reported in the registry record, and no discrepancy is recorded. The sponsor’s reported result is therefore the available inferential comparison. The record does not provide enough detail to reproduce the regression from participant-level data, specify its covariates, or assess how missing observations entered the model. The registry’s confidence interval and p-value should be cited as the sponsor’s analysis, while the descriptive arm means should be identified as such.

The result is a statistical comparison on the registry’s reported scale. Since the sign convention for change and for the net difference is not stated, the numerical estimate does not, by itself, identify which group had a favorable change.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary endpoint and five secondary outcomes. These include quality of life, lung function, episodes of poor asthma control, symptom utility, and airway reactivity. Testing several outcomes creates a multiplicity issue: when many hypotheses are examined, the chance of obtaining at least one apparently notable result can increase, depending on the analysis plan and relationships among outcomes. This is a general statistical consideration, not a claim about what happened in this trial.

Whether the sponsor adjusted for multiple comparisons, used a testing hierarchy, designated some outcomes as exploratory, or otherwise controlled interpretation is not reported in the registry record. Results for the secondary outcomes are not reported in the registry record. Consequently, the primary p-value should not be treated as though the entire family of outcomes has been addressed, and the absent secondary results cannot be interpreted as null findings.

The registry does not report how missing primary-outcome assessments were handled, how many participants contributed data at each follow-up, or whether any imputation or sensitivity analyses were used. The number enrolled and the arm counts in the outcome summary do not establish how many had complete measurements at every visit. Missingness can matter if the likelihood of an unobserved outcome is related to the outcome itself or to treatment group. Without the analysis details, it is not possible to assess that risk from the registry record.

The analysis population is also not reported in the registry record. In particular, the entry does not state whether the primary analysis followed randomized assignment regardless of treatment received, included only participants who adhered to treatment, or used another population definition. Nor does it describe protocol deviations or exclusions. These omissions limit interpretation of the regression estimate and its generalizability to all randomized participants.

Interim analyses and any associated adjustment to statistical testing are not reported in the registry record. The statistical plan, including prespecified outcome hierarchy and missing-data strategy, is not reported in the registry record. These are distinct uncertainties: multiplicity concerns the interpretation of multiple comparisons, while missing-data and population definitions concern which observations inform the estimate. Neither can be resolved by the endpoint summary alone.

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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: severe constipation (100.0%), asthma excerbation (6.0%), elective surgery (1.3%), vomiting and strep throat (0.6%), mood disorder (0.6%).

The serious adverse event summary reports 11 affected participants among 149 at risk in the lansoprazole group and 9 among 157 at risk in the placebo group. The separate other-adverse-event summary reports 93 among 147 at risk and 78 among 150 at risk, respectively. These are registry counts and denominators as posted; they should not be converted into a causal comparison without the trial’s safety definitions, analysis plan, follow-up details, and context for event ascertainment.

The registry lists serious-event terms including Severe constipation, asthma excerbation, Elective surgery, Vomiting and strep throat, Mood disorder, and Pneumonia requiring hospitalization. The percentages displayed alongside these terms are 100.0%, 6.0%, 1.3%, 0.6%, 0.6%, and 0.6%, respectively. The denominator and meaning of those percentages are not reported in the registry record, so they should not be read as rates among all participants or as direct treatment-group risks.

Deaths are not reported in the registry record. A missing death entry cannot be interpreted as confirmation that no deaths occurred. The summary also does not provide event timing, severity grading beyond the serious-event classification, relatedness assessments, or participant-level information. These limitations mean the listed figures are descriptive safety information, not a complete assessment of comparative safety.

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

The result means that the registry reports a model-based comparison of average Juniper Asthma Control Score change between a lansoprazole group and a placebo group. The estimate is 0.2, with a 95% confidence interval from 0.0 to 0.3 and p = 0.12. The arm summaries report means of 1.1 and 1.0. These statistics describe the posted results; they do not, on their own, establish clinical importance.

The score is defined so that a lower score indicates better asthma control, but the registry does not state the arithmetic convention for change or the sign orientation of the net difference. The positive estimate therefore cannot be translated confidently into a direction of benefit using the record alone. The confidence interval communicates uncertainty in the estimated contrast, while the p-value summarizes compatibility with a null comparison under the reported analysis. Neither statistic provides a probability that a treatment is effective.

The result also does not establish whether the observed difference is large enough to matter to patients. A threshold for clinically important change is not reported in the registry record. Nor does the entry establish whether results apply to children with asthma generally, to children with confirmed reflux, or to populations outside the study, because eligibility details and the analysis population are not fully reported.

These findings should not be read as a treatment recommendation. The record does not report results for the five listed secondary outcomes, the detailed missing-data methods, or a complete safety analysis. It also does not provide the protocol or a full statistical plan. The supported conclusion is limited to the posted outcome summaries and sponsor-reported regression result, together with the uncertainties described in the record.

14. Why This Trial Matters Statistically

This trial is statistically informative because it connects a continuous patient-reported asthma-control score to a randomized comparison. The endpoint retains information about changes in score rather than reducing outcomes to a binary category. Reporting both arm summaries and a model-based mean difference gives readers distinct views: the first describes average change within each group, and the second is the sponsor’s direct between-group comparison.

The confidence interval is important because a point estimate alone can hide uncertainty. The reported interval from 0.0 to 0.3 accompanies an estimate of 0.2, while p = 0.12 provides a different summary of the comparison under the regression model. Their joint reading discourages treating a single number as a complete account of the evidence. Rounded endpoints, unspecified sign conventions, and an undisclosed regression specification further illustrate why outcome definitions and analysis details matter.

The registry also makes visible common questions that arise in trial interpretation: how repeated measurements are combined, how missing observations are handled, which participants enter the primary analysis, and whether multiple outcomes were considered together. Those details affect how confidently the reported estimate can be interpreted, but they are not reported in the registry record.

Finally, the distinction between statistical evidence and clinical meaning is central. The record supplies a score direction and a statistical estimate, but it does not give a clinically important threshold or enough information to translate the contrast into a clear direction of benefit. Reading the result carefully means preserving what the analysis reports while avoiding conclusions that the registry entry cannot support.

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 trial-specific details needed for a complete assessment are not reported in the registry record. The eligibility criteria are not fully available, so the exact population of children studied cannot be characterized beyond the asthma focus and the summary’s description of poorly controlled asthma. The record does not establish whether participants had diagnosed gastroesophageal reflux disease. The dosing descriptions are incomplete, and the full treatment schedule cannot be reconstructed.

The endpoint description does not state the arithmetic convention for change from baseline or the sign orientation of the net mean difference. This limits interpretation of whether the reported positive contrast favors one group. The registry does not explain how observations across Weeks 0, 4, 8, 12, and 24 were combined, whether the repeated measurements were jointly modeled, or how incomplete follow-up affected the primary estimate.

The analysis description names linear regression but omits model covariates, diagnostics, and the analysis population. Missing-data handling, protocol deviations, and sensitivity analyses are not reported in the registry record. The registry also does not report the sample-size justification, interim analyses, or a complete multiplicity plan. These absences make it difficult to assess whether the inferential procedure matched the intended analysis strategy.

Results for the listed secondary outcomes are not reported in the registry record. Safety information is limited to summary counts and event terms; definitions, timing, relatedness, and the context for the listed percentages are not reported. Deaths are not reported in the registry record. The posted results therefore support a focused description of the primary endpoint and limited safety summaries, but not a comprehensive evaluation of all outcomes or the full conduct of the trial.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Lansoprazole to Treat Children With Asthma — NCT00442013.
• Registry record last updated 2012-12-06; status last verified 2012-12.
• Results first posted 2012-12-06.
• 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 record describes NCT00442013, titled Lansoprazole to Treat Children With Asthma, as a completed Phase 4 randomized, triple-masked, parallel-group study sponsored by Johns Hopkins University. Enrollment was 306. The study compared daily lansoprazole with matching placebo for 6 months.

The primary endpoint was change in Juniper Asthma Control Score, measured at Weeks 0, 4, 8, 12, and 24. The registry reports arm means of 1.1 and 1.0 and a sponsor-reported linear-regression mean difference of 0.2, with a 95% confidence interval from 0.0 to 0.3 and p = 0.12. The score ranges from 0 to 6, with lower scores indicating better asthma control, but change and contrast sign conventions are not stated.

Five secondary outcomes are listed, but their results are not reported in the registry record. Analysis-population definitions, missing-data methods, multiplicity handling, and the detailed statistical plan are also not reported in the registry record. Safety summaries give serious and other adverse-event counts, but the event context is incomplete.