Penicillin De-labeling in the Pediatric Primary Care Setting: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Penicillin De-labeling in the Pediatric Primary Care Setting (NCT05010304), a na phase 4 study. The primary outcome is Subjects Who Complete Risk-stratification of Penicillin Allergy in the Pediatric Primary Care Setting.

2. Clinical Question

3. Trial Design

This is a completed Phase 4 study of penicillin allergy de-labeling in a pediatric primary care setting. The registry record identifies a single-group model, no masking, and allocation listed as not applicable. Enrollment was 23. The listed intervention is amoxicillin, and the participant group is pediatric patients with a history of penicillin allergy. No separate control arm is reported, so the design does not support a like-for-like comparison between treatment groups.

The record gives a start date of 2021-12-09 and a primary completion date of 2023-10-31. Its status is completed. These dates and status describe the administrative record; they do not establish how many participants completed each assessment or whether the primary aim was achieved.

The study rationale concerns evaluating reported penicillin reactions, risk stratification, and direct amoxicillin challenge in outpatient pediatric primary care. It presents primary care-based assessment as a possible way to address access barriers and describes perceived barriers and knowledge gaps as motivation for the research. These points explain the context but are not trial results.

The registry record does not report a randomized allocation, masking, a comparator, or a statistical analysis plan. It also does not report detailed eligibility criteria, the number of participants who underwent challenge, or a participant flow accounting for enrollment and outcome completion. The record lists three outcome measures, but does not provide a primary endpoint result. Accordingly, the design can be described, but its outcome cannot be quantified from the available registry information.

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 Subjects Who Complete Risk-stratification of Penicillin Allergy in the Pediatric Primary Care Setting, measured over Day 1.

The primary outcome is titled “Subjects Who Complete Risk-stratification of Penicillin Allergy in the Pediatric Primary Care Setting.” Its unit is participants, its measure is a count of participants, and its timeframe is Day 1. In practical terms, it is intended to count how many enrolled participants complete the risk-stratification step.

A completion count is a process or feasibility measure. It can describe whether a planned assessment step was carried out in the study setting. This fits the stated aim of evaluating implementation of risk stratification and direct amoxicillin challenge in outpatient pediatric primary care. A count alone, however, does not show how risk categories were assigned, whether participants proceeded to challenge, or the accuracy of the assessment. Those details and the numerical primary outcome are not reported in the registry record.

In general, endpoint definitions matter because the label of an outcome does not fully specify its operational rules. A clear definition would explain what counts as completion, how incomplete or unavailable assessments are handled, and which participants contribute to the denominator. Such details are not reported in the registry record. The Day 1 timeframe identifies the stated assessment window, but does not provide further information about the assessment procedure.

The outcome should therefore be interpreted narrowly: it is a participant count intended to describe completion of risk stratification, not by itself a measure of challenge safety, successful de-labeling, or a comparative treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count describe?

The primary outcome is a count of participants completing risk stratification, with Day 1 specified as the timeframe. A count reports how many people met an outcome definition. In general, counts are easiest to interpret when the record also describes who was eligible for the outcome, what qualified as completion, and how missing or incomplete assessments were handled. Those operational details are not reported in the registry record. The enrolled total is 23, but that does not substitute for a reported primary outcome count or establish that all enrolled participants were assessed.

The record classifies the outcomes as binary and describes the relevant meaning as participants with an event, reported as counts. That classification does not supply a primary result. No numerical completion count or statistical estimate for the endpoint is reported in the registry record.

What can a single-group design estimate?

In general, a single-group study can describe what happened among participants who were assessed under its procedures. It has no concurrent control group with which to distinguish outcomes associated with the intervention from outcomes that might have occurred under another approach. This study is recorded as single group, with allocation not applicable and no masking. Thus, there is no randomized between-group contrast to interpret. The absence of a comparator is not a flaw to be repaired by statistical adjustment; it defines the question the design can address.

For a feasibility question, descriptive outcomes can be useful, but their interpretation depends on a prespecified and transparent measure of feasibility. Completion counts could describe implementation if the criteria and participant denominator were clear. The registry record does not report such operational detail or the completion result, so no feasibility rate or conclusion can be derived.

What would uncertainty measures add?

In general, a confidence interval is a range of values compatible with the observed data under a stated statistical method. It communicates uncertainty around an estimate; it does not guarantee that the true value lies within that particular interval. For a participant count or a proportion, interval methods depend on the outcome definition and the number of participants contributing data. No confidence interval is reported for the primary outcome. The missing result also means there is no posted estimate whose precision can be evaluated.

In general, a hypothesis test evaluates data against a specified null hypothesis and assumptions. A p-value is not a measure of effect size, does not show the probability that a hypothesis is true, and does not describe clinical importance. The registry record reports no analyses and no p-value for the primary endpoint. No hypothesis, test, adjustment, or model should be inferred from the study title or outcome wording.

How should planning illustrations be read?

In general, sample-size calculations are planning tools that depend on a target effect, variability or event assumptions, significance level, power target, allocation, and analysis method. They do not describe what happened in the enrolled participants. Any planning illustration associated with this study is explicitly described as an illustration computed from an observed effect, rather than the trial’s own design. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect described as a fraction of the observed effect. For non-time-to-event illustrations, the stated convention is participants per arm; for time-to-event illustrations, it is total events.

These assumptions do not match the recorded single-group design: there are no two randomized arms in the study record. The registry does not report a sample-size justification or indicate that these assumptions formed the trial’s protocol. A planning illustration is not observed power, and it cannot replace a result or an uncertainty estimate. Since the registry record does not report the primary result, the assumptions and calculations cannot be independently interpreted as a trial-specific estimate of the effect.

Why do outcome definitions and over-dispersion matter generally?

For count outcomes, a statistical model may account for variation in counts across participants or settings. In general, over-dispersion means that the observed variability is greater than a model’s basic assumptions allow. Ignoring it can make uncertainty estimates too small. Whether over-dispersion is relevant depends on the outcome structure and model; the registry record reports no model or analysis, so it is not possible to say whether it was assessed or relevant.

More broadly, statistical methods should follow the outcome definition and design. A count of participants completing a task is not interchangeable with a binary challenge result, an adverse event count, or a comparative treatment effect. The registry record lists three outcome measures but does not report analyses for them. The appropriate interpretation is therefore descriptive and limited to the information actually recorded, rather than a reconstruction of an unreported analysis plan.

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("Pediatric Patients With a History of Penicillin Al")
n      <- c(23)
events <- c(23)
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  Pediatric Patients With a History of Penicillin Al  23  23  100.0  85.2  100.0  85.7  100.0  85.8  99.9

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists three outcome measures and identifies a primary endpoint concerning completion of penicillin allergy risk stratification. It also names a secondary outcome concerning penicillin allergy labeling in subjects with a negative amoxicillin challenge. The remaining outcome measure is not described in the available record. The record does not report a multiplicity strategy, such as a hierarchy among outcomes or an adjustment for testing multiple hypotheses. Since it reports 0 analyses and no endpoint results, there are no posted inferential results for which the impact of multiplicity can be assessed.

In general, multiplicity matters when several outcomes or comparisons are tested because repeated testing can increase the chance of at least one statistically significant finding under a set of null hypotheses. A prespecified analysis approach can clarify which outcomes are confirmatory and how results should be interpreted. No such approach is reported in the registry record, so it should not be assumed that the outcomes were tested, adjusted, or ranked in a particular way.

Missing-data handling is also not reported in the registry record. The record does not state whether any primary outcome observations were missing, how incomplete risk assessments were treated, or whether all enrolled participants were included in the primary analysis. Enrollment of 23 does not establish the denominator used for the primary outcome.

Analysis populations are not defined in the registry record. It does not state whether the primary analysis included all enrolled participants, only those who began risk stratification, or another group. Because no primary outcome value or analysis is posted, the effect of missing observations or population definitions cannot be evaluated. These omissions limit reproducibility and make it important not to interpret enrollment as proof of endpoint completion.

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.

Most frequent non-serious adverse event terms

The safety record separates serious adverse events, other adverse events, and deaths for pediatric patients with a history of penicillin allergy. For serious adverse events, 23 participants were listed as at risk and 0 as affected. For other adverse events, 23 were listed as at risk and 2 as affected. The reported number of deaths was 0.

These are counts, not comparative estimates. With no separate control group, they do not quantify a difference between strategies. The registry record also does not provide event terms, timing, severity details for the other adverse events, or information that would establish whether an event was caused by the intervention. The absence of reported serious events in this group should not be read as proof that serious events are impossible, nor as evidence about participants outside this study.

In general, safety counts are interpreted in relation to the population monitored, the length and completeness of observation, and the event definitions used. Those details are not reported in the registry record. The available counts therefore describe what the record reports, without supporting a broader safety estimate.

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

The record describes a completed, single-group study with enrollment of 23 pediatric patients who had a history of penicillin allergy. Its primary outcome concerns the count of participants completing risk stratification on Day 1, and its stated aim also discusses direct amoxicillin challenge in primary care. These details identify the feasibility question the study was designed to address.

The record does not report the primary outcome count, the number who completed a challenge, or the result of the secondary outcome concerning penicillin allergy labeling after a negative challenge. It therefore does not show how often risk stratification was completed or whether participants were de-labeled. A completed administrative status is not itself evidence that the intended procedures were completed by participants or that a particular outcome occurred.

Nor does the record establish a treatment effect. The design has no comparator group, and no analyses are listed. It cannot show that primary care-based assessment is better or worse than another strategy, or that an observed outcome was caused by amoxicillin challenge. The safety counts are limited to the recorded participants and do not establish the likelihood of events in other populations.

In general, a feasibility study can inform whether a process appears implementable when it reports clear completion criteria, denominators, and results. That information is incomplete in this registry record. Its enrollment and design provide context, but the missing endpoint results prevent a quantitative conclusion about feasibility. The evidence available supports description of the study setup and recorded adverse-event counts, not a claim of effectiveness, successful de-labeling, or definitive safety.

14. Why This Trial Matters Statistically

This study addresses a statistical question about implementation as well as an intended clinical process: can pediatric primary care carry out risk stratification and direct amoxicillin challenge for appropriate patients? The registry rationale frames the work against access barriers and gaps in knowledge about feasibility. Measuring completion of a planned assessment can be relevant because a procedure’s performance in practice depends not only on its clinical properties but also on whether the steps can be delivered and recorded.

Statistically, however, a feasibility question needs an interpretable endpoint. A participant count can be informative when the record explains what completion means, identifies the relevant denominator, and reports the result. Here, the primary endpoint title and timeframe are available, but the numerical endpoint result and operational completion criteria are not reported in the registry record. This makes the central feasibility question impossible to quantify from the posted information.

The single-group design also sets a clear boundary on interpretation. It can describe outcomes within the study group, but it does not provide a concurrent contrast for estimating relative effects. This matters because process outcomes, challenge outcomes, and de-labeling outcomes answer different questions. The record names these topics but does not report their numerical results or analyses.

The safety counts illustrate another statistical principle: counts need context. The reported numbers refer to the enrolled study group, and details about event definitions and observation are not reported. They cannot be used as a comparative or broadly generalizable safety estimate.

The statistical importance of the record is therefore less about a demonstrated result than about the need for complete outcome reporting. Clear definitions, denominators, analysis populations, and uncertainty estimates would allow readers to evaluate feasibility and precision. In their absence, conclusions should remain bounded by the design and the recorded counts.

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 interpretation is that the registry record does not report a numerical result for the primary endpoint. Although the endpoint is defined by title as a count of participants completing risk stratification on Day 1, the completion count, denominator, and criteria are unavailable. The stated feasibility aim therefore cannot be evaluated quantitatively from this record.

The record also does not report how many participants received direct amoxicillin challenge, the challenge results, or the secondary outcome concerning allergy labeling after a negative challenge. Detailed eligibility criteria, risk-stratification procedures, outcome definitions beyond the titles, and participant flow are not reported in the registry record. These omissions prevent a detailed assessment of who was assessed and how the reported outcomes would have been determined.

The single-group design has no comparator, so it cannot provide a controlled comparison of approaches. No statistical analyses are listed, and the record does not provide estimates of uncertainty, a statistical analysis plan, a sample-size justification, or the handling of missing data. Analysis populations and multiplicity procedures are also not reported in the registry record.

For safety interpretation, the record provides counts but not event descriptions, timing, or fuller monitoring details. These limitations mean that the adverse-event counts cannot be interpreted as a detailed account of event types or as a comparative estimate. The enrollment of 23 is a feature of the record, but without endpoint results and a clear analysis denominator it does not establish the precision or generalizability of any feasibility conclusion.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Penicillin De-labeling in the Pediatric Primary Care Setting — NCT05010304.
• Registry record last updated 2024-08-14; status last verified 2024-07.
• Results first posted 2024-08-14.
• 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 a completed Phase 4, single-group study titled “Penicillin De-labeling in the Pediatric Primary Care Setting.” It lists amoxicillin as the intervention, no masking, allocation as not applicable, and enrollment of 23 pediatric patients with a history of penicillin allergy. The start date is 2021-12-09, the primary completion date is 2023-10-31, and the status is completed.

The primary outcome is a participant count for completion of penicillin allergy risk stratification on Day 1. The stated study aim also concerns direct amoxicillin challenge in outpatient pediatric primary care. The numerical primary result, challenge results, and secondary outcome result are not reported in the registry record. The record lists three outcome measures and 0 analyses.

Safety counts report 0 participants affected by serious adverse events among 23 at risk, 2 affected by other adverse events among 23 at risk, and 0 deaths. The design does not include a comparator, and the record does not report a statistical analysis plan, missing-data methods, or analysis populations.