Oral Iron Versus Oral Iron Plus a Web-based Behavioral Intervention in Young Children (IRONCHILD): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Oral Iron Versus Oral Iron Plus a Web-based Behavioral Intervention in Young Children (IRONCHILD) (NCT04371536), a randomized phase 3 study. The primary outcome is Percentage of Eligible Patients Enrolled.

2. Clinical Question

The study asked whether adding the IRONCHILD web-based behavioral intervention to oral iron therapy could support enrollment and treatment adherence in young children with nutritional iron deficiency anemia. The primary endpoint was the percentage of eligible patients enrolled. The registry record also describes the intervention as aiming to promote caregivers’ understanding and motivation around oral iron adherence. The primary question was therefore about enrollment feasibility, rather than a comparative clinical outcome showing how quickly children improved.

3. Trial Design

The registry record identifies NCT04371536 as a randomized, parallel-group trial with no masking. Its official title describes a single-center, open-label, randomized feasibility trial. The record lists PHASE3 and a total enrollment of 1. The study status is completed; the listed start date is 2021-07-09 and the primary completion date is 2022-02-01.

Participants were intended to receive either oral iron therapy alone or oral iron therapy with the IRONCHILD web-based behavioral intervention. Arm A is described as standard oral iron therapy for 3 months. Arm B is described as the same oral iron therapy plus an intervention developed for caregivers to promote adherence. The registry names ferrous sulfate and IRONCHILD among the interventions.

The posted primary result records 1 participant in Arm A and 0 in Arm B. The endpoint description explicitly states that no enrolled subjects were randomized to Arm B. Thus, although the planned design was randomized and parallel, the posted results do not contain participants in both arms for a comparison. The record does not explain why enrollment stopped at 1, whether recruitment was paused or ended early, or whether the planned enrollment changed.

The primary outcome was percentage of eligible patients enrolled, measured at baseline. The record lists 2 outcome measures, but no secondary outcome results are posted. It lists 0 analyses. The registry record does not report the target enrollment, recruitment period details beyond the listed study dates, allocation procedure, protocol deviations, or analysis populations. The trial is labeled a feasibility trial in its official title, but the registry record does not provide further operational criteria for determining feasibility.

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

Analysis population for the primary outcome, as defined in the registry: No enrolled subjects were randomized to Arm B.

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.

Population: No subjects were enrolled in Arm B. Due to inability to enroll on the trial, it was closed early.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Eligible Patients Enrolled, measured over Baseline.

The primary endpoint is titled “Percentage of Eligible Patients Enrolled” and is measured at baseline. The study description says the hypothesis was that 50% or more of eligible patients would enroll. This endpoint concerns recruitment: it relates the number of eligible people who agree to participate to the number who were eligible. It does not directly measure iron status, adherence, symptom change, or the time required for anemia to improve.

The posted result gives a participant count of 1 in Arm A and 0 in Arm B. The registry does not report the total number of eligible patients approached or assessed. Without that denominator, an enrollment percentage cannot be established from the posted result. The record also says no enrolled subjects were randomized to Arm B, so the arm allocation counts should not be interpreted as a comparison of enrollment percentages between treatment groups.

As a general statistical concept, recruitment endpoints can help assess whether a study’s recruitment approach is workable. Their interpretation depends on a clearly defined eligible population and a denominator that captures who could have enrolled. Neither the number eligible nor additional recruitment details are reported in the registry record. The endpoint therefore documents a very limited enrollment result, but does not establish whether the stated enrollment hypothesis was met.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial is described as randomized, open-label, and parallel-group. Randomization is a method for assigning participants to groups using a chance-based process; it is generally intended to reduce systematic differences between groups at the start of a study. A parallel-group design assigns participants to one group for the study rather than having each participant receive both interventions. Open-label means the registry reports no masking. The record does not give details of the allocation procedure or describe who knew the assigned intervention.

What does the primary endpoint measure?

The primary endpoint is percentage of eligible patients enrolled. In general, a percentage recruitment endpoint requires a numerator—the number of eligible people who enroll—and a denominator—the number of eligible people considered for enrollment. The posted results record 1 participant in Arm A and 0 in Arm B. The total number eligible is not reported in the registry record, so the endpoint percentage is not available. The record’s statement that the study hypothesized that 50% or more would enroll is a target, not a result.

The record identifies the primary outcome parameter as a participant count, despite the endpoint title referring to a percentage. The reported arm values are therefore best read as counts. They should not be converted into a recruitment rate without the eligible-patient denominator. The record does not explain whether the percentage was intended to be calculated from a screening log or another recruitment source.

Why is there no two-arm estimate?

A treatment comparison requires outcome information from both arms in a form that permits the contrast to be estimated. The registry states that no enrolled subjects were randomized to Arm B, and its posted results indicate that values are missing or not estimable for a two-arm comparison with a binary endpoint. It reports 0 analyses. Consequently, no arm-to-arm effect estimate, confidence interval, or p-value is posted.

As a general explanation, a confidence interval conveys uncertainty around an estimated quantity under the statistical model used. It is not a guarantee that the true value lies within the interval. When an estimate cannot be obtained from the available arm data, an interval around a comparative effect cannot be interpreted. The registry record does not provide a model or analysis that would support an alternative comparative estimate.

What can be said about sample size?

The record does not report a sample-size justification for the trial’s own design. It also does not supply a two-arm effect estimate that could support a planning illustration based on the observed effect. The registry explicitly notes that values are missing or not estimable for the binary comparison. Thus, any planning quantities depending on an observed two-arm effect are unavailable rather than evidence about the trial’s statistical power.

As a general concept, a sample-size calculation is a planning exercise based on choices such as the outcome, effect of interest, variability, significance level, and allocation. It is not a measure of the probability that a completed study has found a true effect. A planning illustration, when available, should be understood as conditional on its assumptions and should not be presented as observed power. The assumptions and analysis plan for this trial are not reported in the registry record.

How should sparse data be understood?

With 1 participant recorded in one arm and none in the other, the posted data provide a description of enrollment, not a basis for estimating comparative treatment outcomes. As a general statistical matter, sparse data can make estimates unstable and can prevent standard methods from producing meaningful comparisons. This is especially relevant when an outcome is binary, because the analysis depends on the number of participants and the distribution of outcomes across groups. No method for handling sparse data is reported in the registry record.

The registry lists 2 outcome measures but posts no secondary outcome results. It lists 0 analyses. It does not report whether any analyses were planned but not conducted, or whether any outcome data were collected but not posted. The appropriate interpretation is limited to the information recorded: the primary enrollment count and the adverse-event figures. Missing comparative results should not be filled in by assumptions or reconstructed from unrelated information.

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("Arm A: Oral Iron Therapy")
n      <- c(1)
events <- c(1)
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  Arm A: Oral Iron Therapy  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and 0 analyses. No secondary outcome results are posted. The record does not describe a multiplicity strategy, such as a prespecified approach for controlling the chance of false-positive findings across multiple statistical tests. Since no inferential analyses are posted, there are no reported p-values whose interpretation depends on such an adjustment. Whether multiplicity procedures were planned is not reported in the registry record.

The record also does not describe missing-data methods, imputation, or sensitivity analyses. The lack of participants in Arm B is a feature of the posted enrollment result, not a missing outcome value that can be replaced by an assumed value. The number of eligible patients is not reported, so the recruitment percentage cannot be determined. The record does not specify whether other recruitment information or outcome data were unavailable, uncollected, or not posted.

Analysis populations are not reported in the registry record. In general, a trial analysis population defines which participants are included in a particular analysis and how deviations from assigned treatment are handled. The record does not say whether an intention-to-treat, per-protocol, or other population was planned. With no participant recorded in Arm B, the posted data do not support a comparison across randomized groups in any event.

These omissions matter because analysis choices can influence how results are interpreted. They do not justify assuming that a particular method was used. The registry record does not report a detailed statistical analysis plan, interim analyses, or reasons for the absence of comparative results.

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 registry reports serious adverse events for 1 participant at risk in Arm A, with 0 affected; Arm B has 0 participants at risk and 0 affected. Deaths are recorded as 0 in both arms. These are counts, and the Arm B figures do not represent safety experience among treated participants because none were recorded at risk in that group.

For other adverse events, the registry lists 1 participant at risk and 1 affected in Arm A, compared with 0 at risk and 0 affected in Arm B. The record does not provide further detail about the event or events, and no top serious-event terms are listed. The other-adverse-event figures should not be conflated with serious adverse events: the serious-event count for Arm A is 0, while the other-adverse-event count affected is 1.

As a general statistical concept, safety counts describe what was recorded in the exposed population; they do not by themselves establish whether an intervention caused an event. With only 1 participant at risk in Arm A and none in Arm B, these figures are too limited for a comparative safety assessment. The absence of recorded serious events in this small amount of exposure cannot establish the absence of risk, and the zero values for Arm B cannot be interpreted as safety evidence for the intervention.

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

The posted results establish that 1 participant was recorded in Arm A and 0 in Arm B. They also report 0 serious adverse events among the 1 participant at risk in Arm A, and 1 participant affected by an other adverse event among the 1 at risk there. No participants were recorded at risk in Arm B, and deaths are recorded as 0 in both arms. These observations are descriptive and involve very limited enrollment.

The results do not establish the percentage of eligible patients who enrolled, because the eligible-patient denominator is not reported. The study’s stated hypothesis that 50% or more of eligible patients would enroll therefore cannot be evaluated from the posted figures. The results also do not estimate whether the web-based intervention changed adherence, iron status, recovery, or any other clinical outcome. No two-arm comparison is estimable in the posted record.

As a general statistical principle, a lack of an estimable comparison is different from a finding of no difference. It is also different from evidence that an intervention is effective. The record does not provide an effect estimate, confidence interval, or inferential test that could support either conclusion. It does not report why no participants were randomized to Arm B or why enrollment remained limited to 1.

The appropriate scope of interpretation is therefore narrow: the registry documents a completed feasibility trial with a planned randomized design, but the posted enrollment and outcome information does not answer a comparative treatment question. These data should not be generalized to a larger group or interpreted as evidence for or against the behavioral intervention. The record’s results do not provide a basis for medical decisions.

14. Why This Trial Matters Statistically

This trial raises a useful statistical distinction between a study’s intended design and the data available for analysis. The registry describes a randomized, parallel-group study, yet records no participant randomized to Arm B. A randomized design can support a fair comparison only when outcome information is available across the groups being compared. In this record, the intended comparison is not estimable.

The primary endpoint also illustrates why a percentage needs a denominator. The study aimed to assess the percentage of eligible patients enrolled, but the posted result is a count and the number eligible is not reported. Without that recruitment denominator, the stated enrollment hypothesis cannot be assessed. This is a reporting issue as well as an analysis limitation: readers need to know both how many people enrolled and how many were eligible for the recruitment rate to be interpretable.

The record’s distinction between serious and other adverse events is also important. Counts in a group with only 1 participant at risk, and zero participants at risk in the other group, cannot support a stable comparison. As a general principle, a count can accurately describe what was recorded while still being too limited to characterize the frequency or comparative safety of an outcome.

Finally, the record underscores that feasibility objectives and clinical-effect objectives are not interchangeable. Recruitment and adherence may be relevant to whether a future study can be conducted, while changes in clinical outcomes require their own data and analyses. The registry record identifies the intended intervention and its adherence aim, but the posted results do not establish a clinical effect. Keeping those questions separate helps prevent a small, incomplete comparative dataset from being overinterpreted.

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 is the very small enrollment recorded in the registry: 1 participant in Arm A and 0 in Arm B. The record explicitly states that no enrolled subjects were randomized to Arm B. As a result, it does not provide a two-arm comparison, and values for a binary comparison are reported as missing or not estimable.

The primary endpoint is described as a percentage of eligible patients enrolled, but the total number of eligible patients is not reported. The posted participant counts therefore do not establish the recruitment percentage or whether the stated hypothesis was met. The registry does not give the reason enrollment was limited to 1, explain the absence of participants in Arm B, or describe any recruitment challenges.

Although the record lists 2 outcome measures, no secondary outcome results are posted. It also lists 0 analyses and does not report an analysis plan, analysis populations, missing-data methods, interim analyses, or sample-size justification. Participant characteristics and further details of treatment delivery are not reported in the registry record. The adverse-event counts are based on 1 participant at risk in Arm A and none in Arm B, limiting their descriptive value and preventing a meaningful comparison.

The official title describes a single-center feasibility trial, but the record does not provide additional details about site procedures or operational feasibility criteria. The results should therefore be read as a limited account of enrollment and recorded adverse events, not as an estimate of treatment effect or a broad assessment of feasibility.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Oral Iron Versus Oral Iron Plus a Web-based Behavioral Intervention in Young Children (IRONCHILD) — NCT04371536.
• Registry record last updated 2023-05-06; status last verified 2023-04.
• Results first posted 2023-05-06.
• 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

NCT04371536 is listed as a completed, randomized, open-label, parallel-group trial. Its official title describes a single-center feasibility study of standard oral iron therapy versus oral iron plus the IRONCHILD web-based behavioral intervention for young children with nutritional iron deficiency anemia. The registry lists PHASE3, enrollment of 1, a start date of 2021-07-09, and primary completion on 2022-02-01.

The primary endpoint was percentage of eligible patients enrolled, with a stated hypothesis of 50% or more. The posted result records 1 participant in Arm A and 0 in Arm B, and the record says no enrolled subjects were randomized to Arm B. The number of eligible patients is not reported, so the endpoint percentage cannot be determined. No two-arm comparison is estimable, no secondary outcome results are posted, and the record lists 0 analyses.

For safety, 0 serious adverse events and 0 deaths are recorded in Arm A, which had 1 participant at risk. One participant in Arm A was affected by an other adverse event. Arm B had 0 participants at risk. The registry record does not establish comparative treatment effects or support a comparative safety assessment.