Randomized Controlled Trial of a Patient Activation Tool in Pediatric Appendicitis (Antibiotics Alone vs. Appendectomy): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Randomized Controlled Trial of a Patient Activation Tool in Pediatric Appendicitis (Antibiotics Alone vs. Appendectomy) (NCT02110485), a randomized na study. The primary outcome is Decision Self-Efficacy Scale.

2. Clinical Question

The registry describes a trial about decision support in pediatric appendicitis, where families face a choice between antibiotics alone and appendectomy. Its central comparison is the decision-making support patients and caregivers received: the patient activation tool plus standard consultation versus standard consultation alone. The primary endpoint was measured after the decision, making the timing relevant to interpreting what the score represents. The study was designed to assess confidence in decision making and patient-centered outcomes, not to establish the comparative clinical effects of antibiotics and surgery.

3. Trial Design

The registry record describes a randomized, single-masked, parallel-group trial with an enrollment of 200. The two groups were the Patient Activation Tool arm and the Standard Consultation arm. Participants and caregivers in the first arm received the activation tool in addition to a standard consultation; those in the comparison arm received the consultation alone. The primary endpoint records 98 participants in the tool arm and 102 in the standard-consultation arm.

The study focused on pediatric appendicitis and the decision between antibiotics alone and appendectomy. That treatment choice is the context for the decision-support intervention, not the randomized contrast: the registry lists the tool as the intervention and standard consultation as the comparator. The posted record does not provide enough detail to determine whether every participant faced the same clinical options or how treatment selection was handled after the consultation.

The registry lists the trial as completed, with a primary completion date of 2017-08-31 and a start date of 2014-03-01. It identifies one intervention, the Patient Activation Tool, and describes the masking as single; who was masked is not reported in the registry record. The allocation method is identified as randomized, but details of sequence generation, allocation concealment, stratification, or implementation are not reported in the registry record.

There are six outcome measures and six analyses recorded, while three secondary outcomes are named in the summary information. The record does not give a detailed protocol or a complete account of the study procedures. In particular, a formal sample-size justification, planned interim analyses, and a detailed statistical analysis plan are not reported in the registry record. These omissions limit what can be concluded about the intended design assumptions and analysis decisions beyond the information attached to the posted outcomes.

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 Decision Self-Efficacy Scale, measured over 1 hour following decision.

The primary endpoint was the Decision Self-Efficacy Scale measured one hour after the treatment decision. The scale has 11 questions about confidence in different aspects of decision making. Each item is scored on a five-point scale from 0, not at all confident, to 4, very confident. The described scoring sums the item responses, divides by 11, and multiplies by 25; the resulting score ranges from 0, extremely low self-efficacy, to 100, extremely high self-efficacy. Higher scores indicate greater reported confidence.

This measure is used to capture a participant's perceived confidence in making a decision, a patient-centered construct that is distinct from knowledge, decision quality, treatment choice, or clinical outcome. Because it was assessed after the decision, it reflects reported confidence at that point in time. The registry does not report whether the scale was completed by the child, caregiver, or both, and the population field for the primary outcome is blank. Those details are not reported in the registry record.

The endpoint is summarized by median and interquartile range. A median describes the center of the observed score distribution, while the interquartile range describes the middle half of its values. Scores in the activation-tool and standard-consultation groups both have a median of 100. The corresponding reported interquartile ranges are 95.5 to 100 and 97.7 to 100. These summaries indicate that both group medians are at the scale's upper endpoint, but do not, on their own, capture every difference in the distributions.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous in form, but the registry reports it using a median and interquartile range rather than a mean and standard deviation. This is a descriptive approach that focuses on the middle of the distribution and is less dependent on a symmetric distribution. The median is the midpoint of ordered observations; the interquartile range spans the central half of observations. Neither summary gives the entire distribution, and neither alone describes the uncertainty around a group comparison.

What does a Wilcoxon-Mann-Whitney test compare?

The Wilcoxon-Mann-Whitney test is a rank-based method for comparing observations from two independent groups. In broad terms, it uses the relative ordering of values rather than relying on a comparison of group means. It can be useful when an outcome is ordinal or its distribution does not suit a simple mean-based analysis. A statistically notable result indicates that the observed ranks differ more than would be expected under the test's null model; it does not automatically mean that the medians differ, nor does it express the size of the effect in the original score units.

Interpretation also depends on what aspect of the distributions differs. Under additional assumptions, a rank comparison can be understood in terms of a general tendency for values in one group to be higher than values in the other. Without those assumptions, it is safer to describe it as a difference in distributions or ranks. The registry does not provide a detailed specification of the null hypothesis or an effect estimate for the primary test. The identical reported medians therefore do not contradict the reported test result: different rank patterns can coexist with the same median.

What does a p-value tell the reader?

A p-value is calculated under a specified null model. It describes how incompatible the observed data, or data more extreme according to the test, are with that model. It is not the probability that a treatment has no effect, and it does not measure the practical importance of a difference. A threshold-based interpretation alone leaves out the outcome's scale, the estimated effect, and its uncertainty. A confidence interval would ordinarily help show a range of effect sizes compatible with the data under the analysis; no primary effect confidence interval is reported in the registry record.

The primary comparison is labelled superiority. In a superiority analysis, the question is whether the data support a difference in the direction of the specified comparison, rather than whether two approaches are equivalent. A non-significant result would not establish equivalence. Conversely, a statistically significant result does not by itself establish a large or important difference. Here, the registry reports the test result but does not provide a primary effect estimate that would permit direct assessment of magnitude in score units.

Why can a ceiling matter?

The scale's maximum is 100, and both reported group medians equal 100. This is a ceiling in the median summaries: a score cannot exceed the instrument's upper limit. General statistical reasoning indicates that a ceiling can compress differences among participants with high underlying confidence, because distinct levels above the measurement limit cannot be represented. It can also make the distribution asymmetric. The registry does not report the full distribution or the proportion of scores at the maximum, so the extent of this issue cannot be established from the reported medians and interquartile ranges alone.

The scale description says higher scores are better, but that direction applies to self-reported confidence. It should not be extended automatically to other constructs such as decision quality or clinical benefit. A useful interpretation keeps the measurement close to what was actually collected: a confidence scale measured one hour after the decision.

How should the secondary readmission analysis be understood?

The registry identifies readmission as a secondary outcome and reports a Fisher Exact analysis. Fisher's exact test is a method for assessing association in a two-group categorical comparison. A separate unadjusted recalculation from the posted summary statistics expresses the comparison as a risk difference with a confidence interval and reports an unadjusted p-value. These are not interchangeable descriptions: the risk difference is an effect measure on an absolute scale, while a p-value summarizes compatibility with a null model under a specified test.

For binary outcomes, an effect estimate should be read with its interval, which represents uncertainty as well as the point estimate. An interval spanning zero for a risk difference includes no difference among its compatible values; it also permits differences in either direction if the interval extends on both sides. Such an interval is not proof of equality. The sample sizes for that secondary outcome are smaller than the primary endpoint counts, and the registry does not report why the available counts differ. Missing outcome observations and analysis population details are not reported in the registry record.

What do planning illustrations mean?

Sample-size illustrations based on an observed effect are planning calculations, not observed trial results and not observed power. Their values depend on assumptions, including the effect size targeted, significance level, allocation, and approximation method. The stated planning assumptions use a two-sided significance level of 0.05, equal allocation, and a normal approximation; the illustrations vary the fraction of the observed effect used for planning. They are not a record of the trial's own design justification, which is not reported in the registry record.

Planning from an observed effect can be unstable, particularly when the observed estimate is imprecise. Smaller target effects require larger sample sizes under otherwise similar assumptions. The illustrations should therefore be read as conditional planning scenarios, not as proof that the trial was adequately or inadequately powered. The registry does not report a prospective sample-size justification or the assumptions used by investigators when planning enrollment.

More generally, over-dispersion means that observed variation exceeds what a simpler model assumes. When that happens, standard errors can be too small and confidence intervals too narrow if the model does not account for the extra variation. That concept matters when outcomes have more variability than a model expects, but the registry does not report an over-dispersion assessment for this trial. No conclusion about its presence or handling can be drawn.

10. Analyses Reported by the Sponsor

For the primary endpoint, the registry reports the sponsor's Wilcoxon (Mann-Whitney) analysis as a superiority comparison with p = 0.03. It does not report a primary recalculated effect estimate or confidence interval alongside that test. The primary result should therefore be described using the posted group medians, interquartile ranges, and sponsor-reported test, without implying a numerical between-group difference that is not reported.

For readmission, the registry reports a Fisher Exact analysis with p = .84. A separate unadjusted recalculation from the posted summary statistics uses an absolute risk-difference approach and gives p = 0.782. These values arise from different analysis approaches, so they need not be identical. Both are consistent with the absence of a clear statistical signal in that secondary comparison; neither establishes that the groups are equivalent. The recalculated interval also conveys uncertainty about the size and direction of the difference.

The registry record does not identify a discrepancy between the sponsor's analysis and the recalculation. The sponsor's reported test remains the direct account of the registered analysis. The recalculation is a simple unadjusted analysis of posted summaries and should be understood as a supplementary view, not as a replacement for the sponsor's method or as an adjusted analysis. The detailed analysis plan is not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures and six analyses, and names three secondary outcomes. When several outcomes or analyses are examined, the chance of at least one apparently notable result can rise even if all underlying null hypotheses are true. Statistical approaches to this multiplicity can include a prespecified primary outcome hierarchy, adjusted significance thresholds, or other planned procedures. Whether any such approach was used is not reported in the registry record. The posted p-values should therefore not be interpreted as if the multiplicity issue had been resolved.

The primary endpoint is identified, which helps distinguish the central analysis from secondary questions. However, the registry does not report a detailed statistical analysis plan, the full set of planned analyses, or whether the endpoint hierarchy was specified before data were examined. The absence of those details does not show that no plan existed; it means the plan cannot be assessed from the registry record.

Missing-data handling is also not reported in the registry record. Primary endpoint group counts are 98 and 102, while the readmission analysis includes 83 and 91 participants. The record does not explain the difference in available counts or state whether exclusions, missing measurements, or another analysis-population definition account for it. It would be inappropriate to infer the reason or to assume that missingness was balanced or unrelated to outcomes.

The analysis populations are not defined in the posted record. It is therefore not possible to determine whether the primary analysis followed intention-to-treat principles, used a per-protocol population, or applied another rule. The method used to handle any missing scale items is also not reported in the registry record. These details matter because exclusions and missing-data methods can affect both the estimates and their uncertainty.

The registry does not report interim analyses or stopping rules. No conclusion about whether interim looks occurred, or whether they affected inference, can be made. Taken together, these reporting gaps counsel restraint: the primary test result can be described as posted, but the robustness of the full analysis process, multiplicity control, and handling of incomplete outcomes cannot be independently evaluated from the registry record.

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 adverse-event record lists 98 participants at risk in the Patient Activation Tool group and 102 in the Standard Consultation group. It reports zero serious adverse events in each group, zero other adverse events in each group, and zero deaths in each group. The registry does not list serious adverse-event terms.

These figures describe what was recorded in the posted adverse-event fields. They do not establish that no adverse experiences occurred in any broader sense, and they do not by themselves show that the two approaches have identical safety profiles. The record does not provide event definitions, collection procedures, follow-up completeness, or a detailed account of how adverse events were solicited. Those details are not reported in the registry record.

The study compared decision-support approaches in pediatric appendicitis; the posted safety counts should be interpreted in that context and within the limits of the recorded fields. Zero recorded events do not provide a precise comparison of uncommon risks, and the registry does not report a statistical safety comparison. These data support only the narrow statement that no serious adverse events, other adverse events, or deaths were recorded in the listed groups.

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

The posted primary analysis indicates a difference in the rank distributions of decision self-efficacy scores under the reported Wilcoxon-Mann-Whitney comparison, with p = 0.03. At the same time, both groups have a median score of 100. The result is therefore not a difference between the reported medians. Rather, the test result reflects information in the ordering of observations beyond those two central summaries.

The result does not quantify the size of that difference. The registry does not report a primary effect estimate or confidence interval, so the magnitude and precision of the comparison cannot be expressed in score units from the posted primary analysis. The high medians also warrant attention to the scale's upper limit and the potential for ceiling effects, although the full score distributions are not reported.

The outcome is confidence in decision making one hour after the treatment decision. It does not directly measure whether participants made an informed or values-concordant choice, which treatment they selected, whether they adhered to that choice, or their longer-term health. The trial's focus on a patient activation tool does not mean the primary result establishes a clinical benefit from antibiotics or appendectomy. Those are different questions from the randomized comparison of decision support.

The trial's randomized design is relevant to interpreting the comparison, but important details about allocation, masking, analysis populations, missing data, and multiplicity are not reported in the registry record. The study was intended to assess decision making and patient-centered outcomes, yet not all outcome-level results are available in the posted record. That limits how far the primary finding can be generalized across outcomes or interpreted as a comprehensive account of participant experience.

The appropriate conclusion is narrow: the registry reports a statistically notable rank-based primary comparison, while the group medians are both at the scale maximum. The available information does not establish the magnitude of the difference, its practical importance, or a downstream clinical effect. It also does not establish equivalence between the groups on outcomes where a clear difference was not detected.

14. Why This Trial Matters Statistically

This trial illustrates why a reported p-value should be read together with the outcome summaries and the measurement scale. The primary test is statistically notable, but both medians are 100, the top of the scale. A reader who looks only at medians could miss distributional information used by the rank-based test; a reader who looks only at the p-value could overstate what is known about the size or practical importance of the result.

It also highlights the importance of matching the analysis to the question. The randomized contrast concerns an activation tool added to standard consultation, not antibiotics compared directly with appendectomy. The primary endpoint concerns confidence after a decision, not the clinical consequences of the treatment selected. Keeping intervention, comparator, and outcome distinct prevents a decision-support result from being misread as a treatment-effect result.

The reporting gaps matter statistically as well as descriptively. Without a primary effect estimate and confidence interval, missing-data methods, analysis-population definitions, and multiplicity information, the precision and robustness of the result are harder to assess. A test result alone cannot supply those missing pieces. The secondary outcomes may add useful perspectives, but their interpretive value depends on complete estimates and a clear account of how multiple outcomes were handled.

Finally, planning calculations based on an observed effect are not evidence of the trial's original design adequacy. The registry does not report its prospective sample-size justification. Distinguishing planning illustrations from observed trial findings helps avoid treating a post hoc calculation as a design feature or as observed power. Together, these points make the trial a useful example of careful interpretation: identify the estimand, examine the distribution and scale, separate statistical evidence from magnitude, and respect the limits of registry reporting.

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 limitations specific to this record constrain interpretation. The primary result is reported as a rank-based test and group medians with interquartile ranges, but no primary effect estimate or confidence interval is included. Consequently, the size and precision of the primary contrast cannot be described directly. The identical medians and high scores also make the full distribution important, yet the registry does not report the individual score distribution or how many participants scored at the maximum.

The registry does not report who completed the Decision Self-Efficacy Scale, despite describing it as a participant confidence measure. The primary outcome population field is blank. It is also not clear from the posted information how caregivers and children contributed to the decision or to outcome measurement. These gaps make the measurement unit and respondent perspective less certain than the scale description alone might suggest.

Details of eligibility, implementation of the tool, allocation concealment, the identity of the masked party, and the consultation process are not reported in the registry record. The record also lacks a detailed analysis plan, a prospective sample-size justification, a definition of analysis populations, and an explanation of the smaller available counts for readmission. Missing-data procedures and multiplicity handling are not reported.

Only a subset of the named secondary outcomes has enough posted information to characterize a comparison, and the registry does not give complete numerical results for every measure. The safety fields report no recorded events but do not describe collection or follow-up procedures. These limitations do not negate the posted analysis; they define the boundaries of what can be concluded from the available registry information and prevent a fuller assessment of robustness, completeness, and generalizability.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Randomized Controlled Trial of a Patient Activation Tool in Pediatric Appendicitis (Antibiotics Alone vs. Appendectomy) — NCT02110485.
• Registry record last updated 2019-11-19; status last verified 2019-11.
• Results first posted 2019-07-11.
• 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

NCT02110485 is a completed randomized, single-masked, parallel-group trial with an enrollment of 200. It compared a patient activation tool plus standard consultation with standard consultation alone for pediatric appendicitis decision making. The primary outcome was Decision Self-Efficacy Scale score one hour after the treatment decision, reported as a median and interquartile range and compared using a Wilcoxon (Mann-Whitney) test.

Both groups had a reported median of 100, and the sponsor-reported primary comparison had p = 0.03. The record names secondary outcomes concerning activation, readmission, and quality of life, but complete secondary results are not available in the registry record. The primary effect estimate with confidence interval, missing-data procedures, multiplicity strategy, analysis populations, and prospective sample-size justification are not reported in the registry record. The posted findings concern decision self-efficacy and should not be treated as evidence about the comparative clinical effects of antibiotics and appendectomy.