Early Administration of Steroids in the Ambulance Setting: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Early Administration of Steroids in the Ambulance Setting (NCT03962894), a non-randomized phase 4 study. The primary outcome is Hospital Admission.

2. Clinical Question

3. Trial Design

This is an observational design trial of early administration of systemic corticosteroids in the ambulance setting. The registry lists a Phase 4 designation, nonrandomized allocation, no masking, and a parallel model. It records an enrollment of 834 and a completed status. The listed start date is 2019-04-01 and the primary completion date is 2024-05-31.

The comparison is between children with asthma attacks who receive systemic corticosteroids from EMS before reaching the ED and children receiving usual care, with corticosteroids administered in the ED. Prednisolone is the named drug. The study description identifies multiple EMS agencies and frames the work as a pragmatic observation design. It also describes intended analyses of clinical outcomes, comparative costs, and the influence of EMS transport time. The registry record does not report results for costs or transport-time analyses.

Nonrandomized allocation matters for interpretation. In a randomized trial, assignment is intended to make the treatment groups comparable on average, including factors that may not be measured. In this study, the record does not say how clinicians or EMS personnel selected early treatment, or whether statistical methods were used to account for differences between groups. Children receiving early treatment may therefore differ from those receiving usual care in ways that affect admission or other outcomes. This does not show that such differences occurred; it means that the record does not establish their absence.

No masking is listed. The record does not give additional details about who knew treatment status or how outcome assessments were made. Specific protocol details, eligibility criteria, treatment procedures, and the process for assigning children to the two groups are not reported in the registry record. The design supports describing the comparison that was planned, but the absence of posted outcome and analysis results prevents a conclusion about the observed association.

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.

Before assignment: EMS agencies who decided to incorporate oral systemic corticosteroids as part of clinical care were for this study. The study assigned the start date for EMS agencies to include oral systemic corticosteroids. For the purpose of analysis, we treated that as a stepped wedge protocol design. All agencies contributed one year of data for early prehospital systemic corticosteroids, and one year of data for no prehospital systemic corticosteroids.

Only the first 6 of 7 groups are shown.

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 Hospital Admission, measured over Day 1 (ED stay).

The primary endpoint is the count of participants admitted to an inpatient unit for an asthma exacerbation during the ED stay on Day 1. The definition includes admission to a general inpatient unit or an intensive care unit. It counts participants, rather than measuring duration of admission or the severity of symptoms.

Hospital admission is a direct measure of whether ED care is followed by inpatient care. The study description identifies hospital admission as one outcome of interest in evaluating early corticosteroid administration. The endpoint is therefore relevant to the stated clinical question, but its interpretation depends on the comparison groups and the way the endpoint was measured. In a nonrandomized study, group differences may reflect factors other than treatment timing.

The registry record defines the endpoint but does not report the number of admissions in either group, a treatment-effect estimate, a confidence interval, or a statistical test. It also does not report further details about how admission decisions were standardized or whether the general-unit and intensive-care admissions were analyzed separately. Without posted results, the endpoint definition alone cannot indicate whether the groups differed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry characterizes the primary endpoint as a count of participants with an event: admission to an inpatient unit for an asthma exacerbation during the ED stay on Day 1. Although the endpoint is expressed as a count, a group comparison usually needs the number of participants with the event and the number assessed in each group. Those outcome counts and the analyzed denominators are not reported in the registry record. No numerical estimate of the difference or relative contrast can therefore be interpreted.

What does a confidence interval express?

In general, a confidence interval describes the uncertainty around an estimated effect under the assumptions of the statistical method used. A narrow interval indicates greater precision than a wide interval, while an interval that includes the value representing no group difference may be compatible with both a difference and no difference under that method. The registry record does not report a confidence interval for hospital admission, so the precision of the primary comparison is unknown. General interpretation of intervals also cannot resolve confounding in a nonrandomized study.

What does nonrandomized allocation imply?

In general, random assignment can help balance measured and unmeasured prognostic factors between groups. Observational treatment assignment does not ensure that balance. Statistical adjustment may address measured differences, but cannot automatically remove bias from unmeasured factors or from poorly measured variables. The registry record does not report an adjusted model, covariates, matching, weighting, stratification, or another method for addressing group differences. It is not possible to tell whether any adjustment was performed or how an analysis handled confounding.

The record lists no masking. In general, awareness of treatment status can affect decisions or assessments, depending on the outcome and care setting. Hospital admission is a clinical disposition, but the record does not describe how decisions were made or whether reviewers were unaware of the treatment group. These details should not be assumed.

How should planning calculations be understood?

The registry's sample-size assumptions describe a planning illustration based on the observed effect, not the trial's own design. The stated illustration uses a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation; its target effect is a stated fraction of the observed effect. Such calculations are planning scenarios, not observed trial results and not evidence that a target effect occurred. The registry record does not report a sample-size justification used to design or enroll this study. A planning illustration also is not observed power, and it cannot substitute for the missing outcome estimate and its uncertainty.

In general, power calculations depend on assumptions about the effect to be detected, variability or event frequency, significance level, and allocation. If the assumed effect changes, the planning requirement changes as well. Here, the illustration is described in relation to the observed effect, but the registry record does not give the underlying primary outcome result needed to assess that effect directly. No additional sample-size calculations should be inferred from the enrollment count.

What is known about outcome analysis?

The registry lists two outcome measures and no analysis records. It identifies hospital admission as the primary endpoint and Emergency Department Length-of-stay as a secondary outcome. No statistical test, regression model, effect measure, adjustment strategy, handling of repeated or clustered observations, or method for presenting uncertainty is reported. Because the study involves multiple EMS agencies, methods for accounting for agency-level clustering could be relevant in general, but the record does not say whether clustering was present in the analysis or how it was handled.

In general, over-dispersion matters when count data vary more than the statistical model expects; it can make standard errors too small if ignored. The listed primary measure is a count of participants with an event, not a reported repeated count outcome, and the registry does not report a fitted count model. It would be inappropriate to claim that over-dispersion occurred or that a particular model was used. The main methods conclusion is therefore limited: the endpoint and broad design are described, but the registry record does not report the statistical analysis needed to estimate or evaluate the primary comparison.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Early Prehospital Systemic Corticosteroids", "No Early Prehospital Systemic Corticosteroids")
n      <- c(175, 659)
events <- c(57, 208)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Early Prehospital Systemic Corticosteroids  175  57  32.6  25.7  40.1  26.1  39.8  26.1  39.8
ARM  No Early Prehospital Systemic Corticosteroids  659  208  31.6  28.0  35.3  28.1  35.2  28.1  35.2

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies hospital admission as the primary outcome and Emergency Department Length-of-stay as a secondary outcome. The study description also states an interest in comparative costs and in the influence of EMS transport time. Considering several outcomes or questions can raise multiplicity concerns: when many statistical tests are conducted, the chance of at least one apparently notable result can increase. In general, a prespecified hierarchy or adjustment can help address this issue. The registry record does not report a multiplicity strategy, a hierarchy among additional outcomes, or results for these other questions.

Missing-data handling is not reported in the registry record. There is no description of participants excluded from outcome analyses, missing endpoint values, imputation, or sensitivity analyses. The overall enrollment is 834, but that figure alone does not show how many participants contributed data to each endpoint or whether any observations were missing.

The record does not identify an intention-to-treat population or another defined analysis population. Since allocation was nonrandomized, the usual interpretation of an intention-to-treat analysis in a randomized trial cannot simply be assumed. The record also does not describe any per-protocol, as-treated, or adjusted population. These omissions leave uncertainty about who was included in the outcome analyses and how incomplete records were handled. They do not establish that data were missing or that an analysis population was inappropriate; those details are simply not reported.

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 0% reporting threshold.

The registry reports zero serious adverse events and zero other adverse events in both listed groups. It also reports zero deaths in both groups. The group described as receiving early prehospital systemic corticosteroids has 175 participants at risk for each adverse-event category; the group described as receiving no early prehospital systemic corticosteroids has 659 at risk for each category. No serious adverse-event terms are listed.

These are registry-reported counts, not proof that no adverse events occurred outside the reported data or observation procedures. The record does not describe the adverse-event collection methods, the observation period, event definitions, or whether all enrolled participants contributed safety data. The difference in group sizes also matters when reading raw counts: counts alone do not express rates or comparative risk. No safety effect estimate or uncertainty interval is reported, and none should be inferred from zero counts. These figures describe what the registry record reports; they do not establish equivalence or absence of risk between groups.

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

The registry record establishes that this completed, nonrandomized observational study was designed to compare early prehospital systemic corticosteroids with usual care for children with asthma attacks. It defines hospital admission during the ED stay on Day 1 as the primary endpoint and identifies ED length of stay as a secondary outcome. It also records an enrollment of 834 and describes the study's interest in costs and EMS transport time.

What the record does not establish is whether early treatment was associated with more or fewer admissions, or the size and precision of any difference. The primary admission counts and comparative analysis are not reported. The record also does not provide the secondary outcome results or reported analyses of costs and transport time. A completed status cannot fill these gaps.

Because allocation was nonrandomized, even a posted group difference would need careful interpretation. Patient characteristics, treatment decisions, and EMS or ED circumstances could influence both receipt of early treatment and subsequent outcomes. The registry does not report whether these factors were measured or adjusted for. Thus, the design description alone cannot support a causal claim about treatment timing.

The safety record lists zero adverse events and deaths in the reported groups, but that is not evidence that risk is absent. The methods of ascertainment and duration of observation are not reported. The most defensible reading is that the registry describes the intended comparison and some safety counts, while leaving the principal clinical results and their statistical uncertainty unreported.

14. Why This Trial Matters Statistically

This study addresses a timing question in emergency care: whether systemic corticosteroids administered by EMS before ED arrival are associated with outcomes for children experiencing an asthma attack. The clinical rationale in the registry emphasizes early treatment and identifies hospital admission and ED length of stay among the outcomes of interest. Studying care in an ambulance setting also raises practical questions about how treatment is delivered across EMS agencies.

Statistically, the observational design is central. Comparisons of groups formed through routine treatment decisions can be informative, but differences in outcomes may reflect differences between the groups as well as treatment timing. Clear reporting of group characteristics, outcome counts, statistical adjustments, and uncertainty is therefore important for judging how much an observed association can be trusted. Those results and methods are not reported in the registry record.

The study description also highlights transport time and comparative costs as questions. These topics can matter when translating a clinical strategy into different EMS settings, but the record does not report their findings. The enrollment and completed status indicate the scale and status recorded for the study; neither substitutes for outcome estimates. The statistical importance of this record is therefore both in the question it set out to examine and in the distinction between stated aims and results actually reported.

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 interpreting the clinical question is that the registry record does not report the primary admission counts or a comparative effect estimate. There is no confidence interval or statistical test with which to assess precision or compatibility with no difference. Results for the listed ED length-of-stay outcome, costs, and transport-time questions are also not reported.

Nonrandomized allocation permits potential differences between treatment groups, while the record does not describe how treatment decisions were made or whether any adjustment addressed confounding. No analysis model, measured covariates, handling of EMS-agency clustering, or missing-data approach is reported. The registry also does not report detailed eligibility criteria, dose and route information, endpoint adjudication procedures, or a statistical analysis plan.

The safety counts require caution because event definitions, surveillance procedures, and follow-up duration are not reported. The at-risk counts for adverse events should not be assumed to be the denominators used for the primary endpoint. Finally, the registry lists two outcome measures and no analysis records, leaving the status of outcome analyses and multiplicity procedures unclear. These limitations concern what can be learned from the registry record and do not establish that the underlying study lacked those procedures.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Early Administration of Steroids in the Ambulance Setting — NCT03962894.
• Registry record last updated 2025-05-08; status last verified 2025-04.
• Results first posted 2024-10-24.
• 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 NCT03962894, Early Administration of Steroids in the Ambulance Setting, as a completed Phase 4 observational design trial. It lists nonrandomized allocation, no masking, a parallel model, and enrollment of 834. The study concerns asthma in children and names prednisolone as the intervention.

The primary endpoint is the number of participants admitted to an inpatient unit for an asthma exacerbation during the ED stay on Day 1. The comparison is early prehospital systemic corticosteroids versus usual care, with corticosteroids received in the ED. ED length of stay is listed as a secondary outcome.

Primary outcome results and statistical analyses are not reported in the registry record. The safety counts list zero serious and other adverse events and zero deaths in both groups, with at-risk counts of 175 and 659. The record's completed status does not resolve the missing outcome results.