Evaluation of the Asthma Management Program to Promote Activity for Students in Schools (Asthma-PASS): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of the Asthma Management Program to Promote Activity for Students in Schools (Asthma-PASS) (NCT04576442), a randomized na study. The primary outcome is Symptom Free Days (SFDs).

2. Clinical Question

3. Trial Design

Asthma-PASS was a randomized, parallel-group behavioral intervention trial sponsored by Montefiore Medical Center. The registry lists an enrollment of 452 and a completed status. The recorded start date is 2021-02-09, and the primary completion date is 2025-08-27. The trial phase is listed as not applicable.

The intervention was designed to address several barriers to physical activity and asthma management in schools. Asthma-PASS included primary care provider collaboration, community health worker support, education for children and caregivers, school-level asthma awareness, and training for school personnel. The comparison group received two sessions of basic asthma education and notification of the child’s asthma severity level to the primary care provider.

The record identifies the design as cluster-randomized. This matters for interpretation because people assigned within the same cluster may have more similar outcomes than people in different clusters. The registry material available for this analysis does not state the number or type of clusters, how clusters were allocated, or how many participants were in each cluster. A simple re-analysis that treated every participant as independently randomized would therefore risk misrepresenting the design. The results discussed are the sponsor’s reported analyses, rather than an individual-level re-analysis.

The primary outcome was symptom-free days, measured at baseline and at 3, 6, 9, and 12 months. Physical activity was among the secondary outcomes. The registry lists 9 outcome measures and 16 analyses, but the full analysis plan, outcome hierarchy, and allocation details are not reported in the registry record.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The number of participants analyzed at each timepoint for both arms is depicted in the table below.

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 Symptom Free Days (SFDs), measured over Baseline, 3, 6, 9, and 12 months.

The primary endpoint, symptom-free days (SFDs), measures the number of days in a caregiver-reported 14-day period when the child had no asthma symptoms. A symptom-free day is defined as 24 hours without coughing, wheezing, chest tightness, or shortness of breath. The endpoint is assessed at baseline and at 3, 6, 9, and 12 months.

This measure focuses on the child’s recent symptom experience rather than a single clinical encounter. Repeated assessment can describe how symptom burden changes over follow-up and how the groups’ patterns compare. The registry describes the endpoint as a mean of a continuous measure and gives standard deviation as its dispersion measure. The sponsor’s reported analyses use ratios of rate ratios, which express a relative comparison of rates rather than a direct difference in mean days.

Caregiver report is central to this endpoint: the count reflects the caregiver’s account of the child’s prior 14 days. The registry record does not report additional details about the questionnaire, validation procedures, or how missing daily reports were handled. Nor does the record material available for this analysis specify which of the four reported estimates maps to each follow-up timepoint. Those details affect how specifically the estimates can be interpreted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The reported method is a generalized linear model (GLM) with generalized estimating equations (GEE). A GLM relates an outcome to explanatory variables through a model suited to the outcome’s scale. The registry gives symptom-free days as a mean of a continuous measure, but the sponsor reports the effect parameter as a ratio of rate ratios. The full model specification, including the link function and the exact time and group terms, is not reported in the registry record. The effect should therefore be interpreted using the parameter label and estimates reported, rather than by assuming an unreported model form.

What does a ratio of rate ratios express?

In general, a rate ratio compares rates between groups, and a ratio of rate ratios compares such relative rates across a further dimension, often time or another model contrast. A value of 1 represents equality on that ratio scale. Values above or below 1 indicate a relative contrast in one direction or the other, but which group or time contrast is in the numerator depends on the model’s coding. The registry record does not state the coding or identify the specific timepoint attached to each reported estimate. The ratios cannot be converted to an absolute difference in symptom-free days from the information reported.

Why use generalized estimating equations?

GEE is a population-average approach for estimating relationships when observations are correlated rather than independent. Repeated measurements from the same child are one common source of correlation. In a cluster-randomized study, participants from the same cluster can also share influences and have more similar outcomes. Accounting for such dependence is important: treating correlated observations as independent can make uncertainty estimates misleading. The registry identifies GEE as the sponsor’s method and the trial as cluster-randomized, but does not report the working correlation structure, variance estimator, or exact way clustering and repeated measurements were represented.

GEE does not remove every analytic concern. Its estimates and uncertainty depend on correct specification of the mean model and on suitable handling of the correlation and variance. The record does not provide enough detail to assess those choices. No independent participant-level re-analysis is presented because the registry notes that a simple individual-level re-analysis would be misleading for this cluster-randomized design.

How should the confidence intervals and p-values be read?

Each estimate is accompanied by a 95% confidence interval and a p-value. The interval describes uncertainty around the model-based estimate under the model’s assumptions. For ratio measures, 1 is the null value. The reported intervals are 0.95 to 1.20, 0.93 to 1.19, 0.96 to 1.22, and 1.01 to 1.20. The corresponding p-values are 0.293, 0.395, 0.178, and 0.042. Three intervals include 1; the fourth does not. This describes the individual reported comparisons and does not account for possible multiplicity across outcomes, timepoints, or analyses.

A p-value is a measure of how incompatible the observed data are with a specified null model, given the analysis assumptions. It is not the probability that the null hypothesis is true, nor does it quantify the size or importance of an effect. The record does not state a multiplicity adjustment or whether any analysis was designated in advance as the single confirmatory comparison. As a result, the nominal p-value of 0.042 should not be treated as a complete account of uncertainty across the study’s analyses.

What can be inferred from the outcome format?

The registry describes the primary outcome as a mean continuous measure with standard deviation, while the reported model parameter is a ratio of rate ratios. These descriptions address different aspects of the analysis: the former identifies the type of endpoint and its dispersion summary; the latter identifies the sponsor’s reported comparison scale. Without the full model and estimation details, the distinction cannot be resolved into an absolute mean contrast. No estimate of the difference in symptom-free days, standard error, or model specification is reported in the record details available for this analysis.

Sample-size calculations based on observed effects, when shown as planning illustrations, are hypothetical design exercises rather than evidence about the trial’s observed power. The stated assumptions for such illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The sample-size outputs and any trial-specific sample-size justification are not reported in the registry record details available for this analysis. Such planning illustrations should not be used to claim that the study had a particular observed power.

10. Analyses Reported by the Sponsor

The estimates described in the registry are the sponsor’s own analyses, using generalized linear models with generalized estimating equations. No recalculated estimate or discrepancy between a recalculation and the sponsor’s analysis is reported in the registry record details available for this analysis. Accordingly, there is no independent numerical result to place alongside the sponsor’s estimates. The sponsor’s model-based results are the available estimates and take precedence over a simple unadjusted re-analysis, particularly because the record identifies a cluster-randomized design.

The sponsor reports four ratios of rate ratios, each with a 95% confidence interval and p-value. The registry material available for this analysis does not map those estimates to specific timepoints or provide enough model detail to reproduce them. The reported values should therefore be read as four sponsor-reported comparisons, not as a newly calculated effect or a complete reconstruction of the analysis plan. The record also does not report whether the estimates were adjusted for multiple comparisons.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 9 outcome measures and 16 analyses. The primary endpoint is symptom-free days, and physical activity is listed among the secondary outcomes. Four sponsor-reported estimates are available for the primary outcome, but the record material available for this analysis does not identify the timepoint or comparison attached to each one. It also does not describe a testing hierarchy, state which analyses were prespecified as confirmatory, or report a multiplicity adjustment. Without that information, the estimates and p-values should be viewed as individual reported results rather than as a complete family-wise assessment of the study’s findings.

The record describes enrollment of 452 and says that the number analyzed at each timepoint for both arms is depicted in the primary-outcome table. The actual timepoint-specific analyzed counts are not included in the registry record for this analysis. The registry record does not report how missing outcome measurements were handled, whether participants were analyzed according to their assigned group, or how incomplete follow-up affected the model. It also does not report imputation methods or sensitivity analyses for missing data.

These omissions matter because follow-up measurements may be unavailable for some participants, and the reasons for missingness can influence interpretation. General statistical principle: an analysis that relies on assumptions about missing outcomes can be sensitive to whether those assumptions are reasonable. The available record does not permit evaluation of those assumptions or of the impact of missing data on the estimates.

The exact analysis population is also not reported in the registry record details available for this analysis. The registry identifies the trial as cluster-randomized, but does not give the cluster count, participant flow, or the number of clusters contributing data at each timepoint. Those details would help readers assess whether the reported model reflects the design and how much information supports each estimate.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hospitalization for asthma or respiratory symptoms (4.4%).

The registry reports serious adverse events in 10 of 226 participants at risk in the Asthma-PASS group and 7 of 226 participants at risk in the asthma management comparison group. It reports 0 deaths in each group. The most frequently listed serious adverse event term is “Hospitalization for asthma or respiratory symptoms,” reported as 4.4%. Other adverse events are reported in 63 of 226 participants at risk in Asthma-PASS and 29 of 226 in the comparison group.

These figures are descriptive counts in the registry record. They do not establish that an intervention caused or prevented an event, and they do not by themselves account for differences in exposure time, event severity beyond the registry’s classification, or the study’s cluster-randomized design. The record details available for this analysis do not include event-specific comparison estimates, confidence intervals, or a statistical test of safety differences.

The 4.4% figure is attached to the listed serious-event term; the registry material available for this analysis does not specify its denominator or give further detail about event timing or participant-level recurrence. The figures should therefore be read as reported safety summaries, not as a standalone comparative safety analysis.

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

The posted results document a randomized evaluation of a school-based program intended to address asthma management and barriers to physical activity. The primary outcome captures caregiver-reported symptom-free days over the prior 14 days, assessed repeatedly from baseline through 12 months. The sponsor reports four relative estimates from generalized linear models with generalized estimating equations.

Three of the four reported confidence intervals include 1, while one is above 1 and is paired with p=0.042. This pattern describes the reported comparisons but does not establish a uniform effect across follow-up. The registry material available for this analysis does not identify which estimate corresponds to which timepoint, give an absolute change in symptom-free days, or report a threshold for clinical importance. The ratio estimates should not be translated into a count of additional symptom-free days.

The registry record also does not report whether the results were adjusted for the multiple outcomes and analyses listed, how missing measurements were handled, or the detailed model specification. Those gaps limit how firmly the four estimates can be interpreted as a coherent pattern of evidence. The cluster-randomized design further means that a participant-level analysis that ignores clustering would not be an appropriate substitute for the sponsor’s analysis.

These findings do not establish whether the program should be adopted, nor do the safety counts establish a causal difference in adverse events. They describe the trial design, outcome, and analyses reported in the registry. General statistical principle: an estimate needs to be considered alongside its precision, analysis assumptions, design, and clinical context; a p-value alone cannot establish clinical importance or a treatment’s overall value.

14. Why This Trial Matters Statistically

This trial raises important statistical issues because its intervention operates across several settings: primary care, families, community health workers, and schools. The registry identifies a cluster-randomized design, so the unit of assignment and the pattern of shared influences are relevant to both estimation and uncertainty. A conventional comparison that treats every child as independently randomized would not reflect the design described in the record.

The primary endpoint is measured repeatedly, using caregiver reports of symptom-free days over a 14-day recall period. Repeated outcomes can provide information about patterns over time, but they also create correlated observations. GEE is a method commonly used for population-average analyses of correlated data. The record names this approach, while leaving its detailed specification unreported. Readers therefore need to distinguish the stated method from an independently reproducible analysis.

The four reported ratio-of-rate-ratios estimates also illustrate why effect scale and analysis labels matter. Such a ratio is not automatically interpretable as a number of symptom-free days. The registry does not map the estimates to follow-up visits, describe their exact contrasts, or report a clinically important threshold. Without those details, the values support only a limited reading of the sponsor’s relative comparisons.

Finally, the registry lists 9 outcome measures and 16 analyses, while the record details available for this analysis do not state how multiplicity was handled or how missing measurements affected the results. These are not minor technical details: they shape how readers judge the precision and strength of a collection of findings. The trial is thus a useful example of why design-aware analysis, transparent outcome mapping, and clear reporting of missing-data and multiplicity decisions are central to interpreting clinical research.

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 registry record details available for this analysis leave several trial-specific details unclear. Although the design is identified as cluster-randomized, the number and type of clusters, allocation procedures, and cluster-level participant distribution are not reported. The record names GEE as the sponsor’s method but does not provide the full model specification, including the correlation structure, variance estimator, covariates, and coding of the relative contrast. This prevents a detailed assessment or reproduction of the sponsor’s estimates.

The primary outcome is assessed at baseline and at 3, 6, 9, and 12 months, but the four reported estimates are not mapped to particular visits in the record material available for this analysis. There is no reported absolute difference in symptom-free days or clinically important difference threshold. Therefore, the estimates cannot be translated into a straightforward measure of the number of symptom-free days associated with either group.

The record lists 9 outcome measures and 16 analyses but does not report a testing hierarchy or multiplicity adjustment. It also does not report the timepoint-specific analysis counts in the registry record for this analysis, the missing-data strategy, the analysis population, participant flow, or sensitivity analyses. These gaps limit assessment of attrition and the robustness of the findings.

The safety summaries provide counts and a serious-event term, but no comparative uncertainty estimates or further event details. The record details also do not provide a trial-specific sample-size justification. These limitations do not invalidate the reported results, but they constrain how precisely the findings can be interpreted from the registry information alone.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of the Asthma Management Program to Promote Activity for Students in Schools (Asthma-PASS) — NCT04576442.
• Registry record last updated 2026-10-30; status last verified 2026-10.
• Results first posted 2026-10-30.
• 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

Asthma-PASS (NCT04576442) was a completed randomized, parallel-group behavioral trial sponsored by Montefiore Medical Center, with enrollment of 452. The recorded start date was 2021-02-09, and the primary completion date was 2025-08-27. The population was children with asthma.

The intervention combined primary care collaboration, community health worker support, child and caregiver education, school asthma-awareness promotion, and school personnel training. The comparison group received basic asthma education and primary care provider notification of asthma severity.

The primary outcome was caregiver-reported symptom-free days at baseline and at 3, 6, 9, and 12 months. The sponsor reported four ratios of rate ratios from generalized linear models with generalized estimating equations. The record identifies cluster randomization, but does not report key model details, the mapping of estimates to timepoints, multiplicity handling, or missing-data methods in the registry record for this analysis.