Understanding Childhood Infection, Inflammation and Allergy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Understanding Childhood Infection, Inflammation and Allergy (NCT01022268), a registered phase not stated study. The primary outcome is What Are the Bacterial and Viral Causes of Acute Illness in Children Presenting to a UK General Hospital, Tertiary Paediatric Infectious Disease Unit and Paediatric Intensive Care Unit?.

2. Clinical Question

3. Trial Design

The record describes a completed clinical and academic programme focused on childhood infectious, inflammatory and allergic disease. Its stated aim was to improve diagnosis and understanding by establishing groups of patients with defined conditions and studying microbiological and patient samples. The planned scientific interests included genetic background, differential gene expression, proteomics and pathogen type.

The registry lists Imperial College London as sponsor and enrollment of 902. The study started on 2009-07-20, with primary completion on 2018-08-30; its status is completed. The record describes recruitment of unwell children coming to hospital through any route and of controls who required blood tests for elective or other clinical reasons. The clinical description identifies St Mary’s Hospital as a recruitment setting and refers to its paediatric services. The programme description also mentions clinical and academic staff at Imperial College and St Mary’s Hospital, Southampton Hospital and John Radcliffe Hospital.

This was not a randomized treatment trial. The registry does not state allocation, and it explicitly cautions that the arms are not a like-for-like control comparison. The control group is defined by the absence of an infectious, inflammatory or allergic condition, rather than by random assignment to an alternative treatment. The record does not report a treatment intervention, a protocol for allocating participants, or a statistical analysis plan.

Children were monitored for the primary outcome throughout their hospital stay and received follow-up review at 10 days. The registry does not report further details of follow-up procedures, how many participants completed follow-up, or whether the follow-up schedule differed across groups. The record lists one outcome measure and no analyses. It therefore describes the study’s purpose and outcome definition, but does not provide a primary-outcome estimate or a group comparison.

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: Controls did not present with infectious, inflammatory or allergic conditions - and therefore all patients under the control category had a phenotype of 'healthy' - with none of them meeting criteria for the other phenotype groups (bacterial, viral, inflammatory, uncertain, other).

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 What Are the Bacterial and Viral Causes of Acute Illness in Children Presenting to a UK General Hospital, Tertiary Paediatric Infectious Disease Unit and Paediatric Intensive Care Unit?, measured over Participants were monitored for outcome throughout their stay in hospital, and received follow-up review at 10 days.

The primary outcome is a participant count: children with a phenotype classified as definite bacterial disease or definite viral disease, based on culture or molecular investigations of samples from a sterile site. The registry describes monitoring throughout the hospital stay and follow-up review at 10 days. It does not report the observed number of participants meeting this definition.

As a general statistical point, a phenotype definition translates clinical and laboratory information into a category that can be counted. Using culture or molecular investigations from a sterile site gives the outcome a specified microbiological basis. This can help distinguish cases with evidence supporting a definite bacterial or viral classification from other clinical categories. The record does not provide further diagnostic criteria, test-performance information, or rules for resolving conflicting findings, so those details cannot be assessed.

The outcome is not a treatment-response measure. It is a classification of disease aetiology among children in the study setting. The record also describes controls as healthy for the phenotype categories: control participants did not have an infectious, inflammatory or allergic condition and did not meet criteria for the bacterial, viral, inflammatory, uncertain or other phenotype groups. The endpoint therefore serves the programme’s diagnostic and descriptive aims, but the posted record does not give outcome counts by group or an estimate of how precisely any group difference was measured.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a count of participants with definite bacterial or definite viral disease. The outcome is binary at the participant level: each participant either meets a stated phenotype classification or does not. As a general statistical explanation, binary outcomes are often reported as counts and proportions, with uncertainty intervals to show how precisely the underlying frequency is estimated. The registry record does not report the outcome counts, proportions, or uncertainty intervals, so none can be interpreted for this study.

What does a confidence interval communicate?

As a general concept, a confidence interval expresses the uncertainty around an estimate under the assumptions of the analysis method. A narrower interval indicates greater precision, while a wider interval indicates less precision. It does not show the range of individual participant outcomes, and it does not by itself establish whether a finding is clinically important. No confidence interval for the primary outcome is reported in the registry record.

What is the role of a comparison?

A group comparison requires a clearly defined contrast and an analysis that accounts for how participants entered each group. Here, the registry describes children presenting with infectious, inflammatory or allergic conditions and controls without those conditions. It states that allocation is not reported and that the arms are not a like-for-like control comparison. In general, differences between groups defined by clinical status can reflect underlying differences in the populations as well as any process being studied. Randomization is not described, and the registry record does not report an adjusted model or other method for separating these influences.

What does the outcome definition establish?

The outcome uses culture or molecular investigations of samples from a sterile site to classify definite bacterial or viral disease. In general, a prespecified operational definition can make outcome classification more consistent by identifying what evidence qualifies. The registry does not report detailed classification rules, blinded adjudication, handling of conflicting test results, or the performance of the diagnostic methods. Those omissions limit assessment of how reliably the endpoint was assigned.

How should planning calculations be read?

The registry describes sample-size assumptions for planning illustrations: two-sided significance level 0.05, equal allocation between the two arms, and a normal approximation. The target effect is expressed as a stated fraction of the observed effect. For time-to-event planning, the stated quantity is the total number of events; for other outcomes, it is participants per arm. These are planning assumptions, not a report of the original study’s design or a measure of its observed power. The registry does not report the study’s own sample-size justification, the effect estimates used in any planning illustration, or an original statistical plan. If a posted recalculation differs from a sponsor analysis, the sponsor’s own analysis takes precedence.

Why can over-dispersion matter?

As a general point, over-dispersion occurs when observed variability exceeds what a statistical model assumes. Ignoring it can make uncertainty estimates too small and statistical evidence appear stronger than warranted. The primary outcome is a participant count with binary classification; the record does not identify an over-dispersion parameter or a model that accounts for it. The registry therefore provides no basis for concluding that over-dispersion was assessed or relevant to the primary analysis.

What can be inferred from the listed analysis status?

The record lists one outcome measure and no analyses. In general, an outcome definition alone is not a result: interpretation also requires the observed counts, analysis population, treatment of missing data and method used to estimate uncertainty. Those analysis details are not reported in the registry record. Consequently, the posted information cannot establish an effect size, statistical significance, or precision for the primary endpoint.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. It does not report a multiplicity strategy, such as whether any secondary or exploratory outcomes were tested alongside the primary outcome or how multiple statistical tests would be handled. The record also does not state an analysis plan, so it is not possible to determine whether the outcome definition or analysis was prespecified in a protocol.

Missing-data methods are not reported in the registry record. There is no information about missing outcome classifications, incomplete follow-up, exclusions, or how participants without a definitive culture or molecular result were handled. The record says participants were monitored throughout their hospital stay and received follow-up review at 10 days, but it does not report follow-up completeness or the number included in any analysis.

The analysis population is also not reported. The registry does not say whether all enrolled participants were included in an analysis, whether participants were excluded after enrollment, or how phenotype categories were assigned when information was incomplete. These details matter because missing test results or follow-up can affect the set of participants contributing to a count and the interpretation of that count.

As a general statistical point, clear reporting of missingness and analysis populations helps readers judge whether an estimate represents the intended group and whether exclusions could influence the result. Here, no primary-outcome estimate or analysis is posted, so the effects of missing data, exclusions and multiplicity cannot be evaluated.

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

The record describes a hospital-based programme intended to improve diagnosis and understanding of childhood infectious, inflammatory and allergic conditions. Its primary question concerns bacterial and viral causes of acute illness, and its endpoint specifies a microbiological basis for classifying definite disease. These details clarify what the study sought to describe.

The record does not report the primary-outcome counts or an analysis comparing groups. It therefore cannot establish how common definite bacterial or viral disease was in the enrolled population, how precisely those frequencies were estimated, or whether the groups differed. No result should be inferred from the enrollment figure alone.

The controls were defined by not having an infectious, inflammatory or allergic condition, while the other group included children presenting with those conditions. The record cautions that the arms are not a like-for-like control comparison and does not state allocation. A contrast between these groups would not, by itself, demonstrate that a study procedure or treatment caused a difference.

The registry’s adverse-event entries list 3 deaths in the infection, inflammation or allergy group and 0 in controls. They do not report causes, timing, attribution or analysis, so these counts alone do not establish a relationship to study participation. The absence of reported serious or other adverse-event counts in the listed fields should not be taken as proof that no events occurred beyond what the registry records.

In short, the posted information describes study purpose, recruitment groups and endpoint definition. It does not provide evidence to estimate a disease frequency or treatment effect, nor does it support a causal conclusion or a claim about diagnostic performance.

12. Why This Trial Matters Statistically

This study is statistically notable as a cohort and diagnostic research programme rather than a randomized treatment comparison. Its central question concerns the causes of acute illness among children seen in hospital services, and the primary outcome is a participant count based on microbiological evidence from sterile-site samples. That distinction matters: descriptive classification and causal treatment evaluation answer different questions.

The definition of the control group is also important to interpretation. Controls did not have the infectious, inflammatory or allergic conditions under study, and the registry cautions that the arms are not a like-for-like comparison. A group contrast would therefore require careful attention to the populations represented and to the purpose of the analysis. The record does not report an adjusted comparison.

The registry provides a substantial programme context, including the intent to study genetic background, gene expression, proteomics and pathogen type, but it does not provide analysis results for the primary outcome. The contrast between a detailed scientific aim and an absent outcome analysis illustrates why a registry record’s endpoint definition cannot substitute for an estimate, its uncertainty and a transparent analysis method.

Finally, the stated planning assumptions are distinct from evidence about the completed study’s results. Planning illustrations use assumptions about significance level, allocation, approximation and target effect; they are not observed power. For readers, keeping design, measurement and analysis separate is essential to interpreting what this record can and cannot establish.

13. 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 primary limitation for statistical interpretation is that the registry record does not report the primary-outcome counts or any analysis. There is no estimate of the frequency of definite bacterial or viral disease, no confidence interval, and no reported group comparison. Although enrollment is listed as 902, the record does not say how participants were distributed across groups or how many contributed to the endpoint analysis.

The outcome is defined by culture or molecular investigations from a sterile site, but detailed diagnostic criteria and classification procedures are not reported. The record does not describe how indeterminate, conflicting or unavailable test results were handled. It also does not provide information about diagnostic test performance or outcome adjudication.

The comparator is limited for causal interpretation: controls did not have the conditions under study, allocation is not stated, and the registry warns that the arms are not a like-for-like control comparison. No adjustment strategy or statistical model is reported. Missing-data procedures, analysis populations and follow-up completeness are likewise not reported in the registry record.

The adverse-event entries provide counts but no timing, cause or attribution. The registry does not report the original sample-size justification or statistical analysis plan. These gaps mean the record can be used to understand the study’s aims and endpoint definition, but not to assess the precision, robustness or causal meaning of a primary-outcome result.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Understanding Childhood Infection, Inflammation and Allergy — NCT01022268.
• Registry record last updated 2022-11-21; status last verified 2022-04.
• Results first posted 2022-11-21.
• 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.

17. Record Summary

This completed study, sponsored by Imperial College London, examined childhood infection, inflammation and allergy in a hospital-based programme. The registry lists enrollment of 902, a start date of 2009-07-20 and primary completion on 2018-08-30.

The primary question concerns bacterial and viral causes of acute illness in children presenting to hospital services. The outcome counts participants with definite bacterial or viral disease, based on culture or molecular investigations of samples from a sterile site. The record describes controls without infectious, inflammatory or allergic conditions and cautions that the groups are not a like-for-like comparison.

The registry lists one outcome measure and no analyses. Primary-outcome counts, estimates and uncertainty are not reported in the registry record. The available information therefore describes the study’s purpose and measurement approach, but does not establish a quantitative result.