Safety of Artificial Pancreas Therapy in Preschoolers, Age 2-6: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety of Artificial Pancreas Therapy in Preschoolers, Age 2-6 (NCT04084171), a na na study. The primary outcome is Primary Outcome.

2. Clinical Question

The study is identified as NCT04084171 and titled “Safety of Artificial Pancreas Therapy in Preschoolers, Age 2-6.” Its brief summary describes a single-arm, multi-center clinical study assessing the safety profile of the system under free-living conditions in children with type 1 diabetes aged 2-6 years old.

The clinical question is descriptive rather than a comparison of randomized treatment groups. The primary outcome asks whether each participant met two glycemic thresholds and then expresses the result as a percentage of subjects. The registry record does not report the observed percentage or participant-level outcome counts, so the answer to that primary question cannot be read from the record.

The record lists secondary outcomes using additional thresholds for time below 70, 60, 54, and 50mg/dl; time above 180, 250, and 300 mg/dl; and time between 70-140mg/dl. Their definitions indicate other glycemic summaries of interest, but outcome values are not reported in the registry record.

3. Trial Design

This was a completed, single-group study with enrollment of 12 participants. The registry identifies the intervention as a device: Tandem t:slim X2 with Control-IQ Technology + Dexcom G6. The arm description states that participants used the system to automatically modulate insulin delivery and control glycemia. The brief summary describes the study as multi-center and conducted under free-living conditions.

The record lists allocation as NA, masking as NONE, and the model as SINGLE GROUP. There is therefore no randomized allocation between treatment arms and no parallel control arm described. The baseline period was Open Loop use before the hotel admission, while the later period involved Control IQ. Because the periods occurred sequentially in the same study rather than as randomized concurrent groups, their contrast cannot isolate the system’s effect from other time-related or study-context differences.

The primary outcome timeframe describes baseline results as coming from 2-7 day of Open Loop use, with a median of 4 day, before the hotel admission. AP results are described as coming from the 5 day study admission using Control IQ, including 48 hours of supervised hotel admission followed by 72 hours at home. These are short observation periods. They describe the timing of measurements but do not establish how representative those periods are of longer-term use.

The registry lists phase as NA and status as COMPLETED. The start date is 2019-09-26 and primary completion is dated 2019-10-23. The record does not report a statistical analysis plan, a sample-size justification, or a randomized control comparison. It lists 15 outcome measures and zero analyses. Consequently, this design information supports describing the study setup, but not estimating comparative effectiveness or drawing broad conclusions about outcomes beyond the periods described.

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: All participants enrolled completed the study.

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 Primary Outcome, measured over Baseline results are from the 2-7 day (median of 4 day) use of Open Loop before the hotel admission. AP results are from the 5 day study admission using Control IQ including 48 hours of supervised hotel admission followed by 72 hours at home..

The primary outcome is the percentage of subjects with less than 6% time below 70mg/dL and less than 40% time above 180mg/dL. It is a participant-level, joint criterion: a participant must meet both the low-glucose and high-glucose thresholds to count as meeting the stated outcome. The endpoint then expresses the number meeting that criterion as a percentage of subjects.

This type of endpoint can summarize two distinct aspects of glucose exposure in a single measure. The below-70mg/dL condition captures time under a specified low-glucose threshold, while the above-180mg/dL condition captures time over a specified high-glucose threshold. Requiring both conditions means the endpoint is not simply a measure of either low or high glucose considered separately. The registry also lists secondary outcomes at other glucose thresholds and for time between 70-140mg/dl.

In general, endpoints are chosen to make a study question measurable and to specify what observations count as meeting the outcome. Here, the percentage format describes how common the joint criterion was among the participants assessed. The registry record does not report the observed primary outcome value, the numerator or denominator used for the reported endpoint, or a confidence interval. Thus the endpoint’s definition is available, but the result and its precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a percentage outcome in a single-group study. Understanding that endpoint requires separating its definition, its measurement period, and the analysis used to turn participant observations into a result. The definition is present, but the registry record does not report the primary outcome value or an analysis of it.

What does the primary endpoint count?

The endpoint describes the percentage of subjects meeting two conditions together: less than 6% time below 70mg/dL and less than 40% time above 180mg/dL. The joint wording matters. A participant who met only one threshold would not meet the combined definition as written. The endpoint therefore represents the share meeting the full criterion, rather than two separate percentages or an average glucose measurement.

In general, a percentage is a proportion expressed on a scale from none of the assessed participants to all of them. Its interpretation depends on knowing which participants were assessed and how the numerator and denominator were defined. The registry record does not report those primary-outcome counts or specify the analysis population in the primary outcome entry. The percentage cannot be reconstructed from the description alone.

How should the observation periods be understood?

The timeframe distinguishes baseline Open Loop use from AP use with Control IQ. Baseline results are described as coming from 2-7 day, with a median of 4 day, before hotel admission. AP results are described as coming from a 5 day study admission, including 48 hours of supervised hotel admission followed by 72 hours at home. This information establishes the measurement context stated in the record. It does not establish that observations were complete for every participant, nor does it say how measurements were aggregated across days.

In general, time-in-range outcomes summarize time spent within or outside specified glucose thresholds. Their values depend on the measurement window and the rules used to process observations. The registry record does not report the measurement-processing rules, completeness requirements, or handling of missing observations. These details should not be inferred from the endpoint wording.

What does a single-group sequence allow?

The registry lists a SINGLE GROUP model, allocation NA, and masking NONE. The Open Loop baseline preceded Control-IQ use; it is not a parallel randomized control group. In general, a within-participant sequence can describe measurements in different periods, but changes over time may coincide with changes in setting, supervision, behavior, or other factors. Without a concurrent randomized comparison and an analysis addressing relevant differences, a temporal contrast is not by itself a causal estimate.

The stated AP period includes both supervised hotel admission and time at home. Those settings are part of the described timeframe, but the registry does not report separate outcome estimates for them. It also does not report an analysis comparing outcomes by setting. The record therefore supports describing the periods, not inferring that one setting produced a particular result.

What is statistical uncertainty?

General: a confidence interval is a range of values that expresses uncertainty around an estimate under a specified statistical procedure. For a percentage outcome, it would help readers understand how precisely the observed proportion is estimated. The registry record does not report a confidence interval for the primary endpoint. It also reports zero analyses, so there is no posted inferential estimate from which to assess uncertainty or statistical significance.

General: a p-value is one way to summarize how compatible data are with a specified statistical null model. It does not measure the size or practical importance of an effect. No p-value or corresponding primary-endpoint analysis is reported in the registry record. It would therefore be inappropriate to characterize the endpoint as statistically significant or nonsignificant based on this record.

What are planning calculations?

General: sample-size planning uses assumptions about an outcome, a target effect, and an analysis to illustrate how many observations may be needed for a planned study. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. The record says time-to-event calculations give the total number of events, while other calculations give participants per arm.

Those assumptions describe planning illustrations, not the design of this single-group trial. The record does not report the trial’s own sample-size justification, and the planning assumptions do not turn this study into a two-arm randomized comparison. Any planning figures should be treated as illustrations under their assumptions, not as observed power or as trial results. The registry record does not report an analysis plan that would link such calculations to an actual inferential analysis of the primary outcome.

General: over-dispersion occurs when outcome variability exceeds what a chosen statistical model assumes. It can affect uncertainty estimates and the performance of statistical tests. The registry record does not identify an over-dispersion model or describe a model for the primary endpoint; therefore, no claim about such an adjustment can be made for this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 15 outcome measures, including the primary endpoint and secondary glycemic outcomes using several thresholds. When multiple outcomes are examined, general statistical practice considers multiplicity: repeated testing can increase the chance of at least one apparently unusual result under a collection of null hypotheses. Methods for addressing this may include a prespecified hierarchy or an adjustment, but the registry record does not report a multiplicity strategy or analysis plan. No adjustment should be assumed.

The record lists zero analyses. It does not report results for the primary or secondary outcome measures, nor does it describe any statistical tests. As a result, there is no reported set of outcome tests from which to determine whether multiplicity affected interpretation. The number of outcome measures alone does not establish that all were tested, or that any particular adjustment was used.

Missing-data handling is not reported in the registry record. The primary outcome population is not specified in the outcome entry, and the record does not explain whether participants with incomplete glucose measurements were included, excluded, or handled by another method. It also does not report the extent or pattern of missing outcome data. No imputation method or sensitivity analysis is described.

The analysis populations are likewise not reported in the registry record. The enrollment figure is 12, but enrollment alone does not establish the number contributing to a particular endpoint. It would be inappropriate to assume that all enrolled participants had complete measurements or were included in every outcome analysis. The same caution applies to the reported safety counts: the group lists 12 at risk, but no further analysis population definitions are given.

These omissions limit interpretation of both the endpoint denominator and the reliability of any estimate. They do not show that missingness or multiplicity problems occurred; rather, the registry does not provide enough information to evaluate how either was handled.

11. 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 safety record lists one group, Artificial Pancreas Therapy, with 12 participants at risk. It reports zero participants affected by serious adverse events, zero participants affected by other adverse events, and zero deaths. No top serious adverse event terms are listed.

These figures describe the counts recorded for the group and should not be read as a guarantee that no adverse events are possible. In general, observing zero events in a study does not establish that the underlying risk is zero, particularly when the number of participants and the observation period are limited. The study enrolled 12 participants, and the primary outcome timeframe describes a 5 day AP study admission, including supervised hotel admission and time at home. The registry’s safety entry does not give a separate safety observation duration.

The record does not provide event narratives, severity details beyond the serious-versus-other grouping, or event-specific terms. It also does not report a comparison group. Accordingly, the counts are descriptive and do not support a comparative estimate of safety between treatments. They should be interpreted alongside the small enrolled group and the study’s stated observation context, without extending them to longer-term use or to populations not described in the record.

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

The record establishes that a completed single-group study enrolled 12 children and assessed use of the Tandem t:slim X2 with Control-IQ Technology and Dexcom G6. It gives a primary endpoint definition based on two glucose-time thresholds, describes baseline and AP observation periods, lists secondary outcome thresholds, and reports safety counts. These details explain what the study was set up to examine.

The central primary outcome result is not reported in the registry record. There is no posted percentage meeting both endpoint criteria, no outcome count, and no confidence interval. The listed outcome thresholds cannot be taken as evidence that the thresholds were met. The record also lists zero analyses, so it does not provide a statistical test or an estimate of the difference between baseline and AP periods.

The design is not a randomized comparison. Open Loop measurements preceded the Control-IQ period, and there was no parallel control group described. In general, sequential observations can be informative descriptively, but a change between periods could reflect factors other than the intervention. The registry record does not report an analysis that would separate these possibilities. The design therefore does not support a causal comparison with another treatment from the information recorded.

The safety entry reports zero serious adverse events, zero other adverse events, and zero deaths among 12 participants at risk. These counts are relevant descriptive information, but they do not demonstrate an absence of risk or establish longer-term safety. The registry record does not report event-specific terms or a comparison group.

In short, the registry supports a description of the study design, outcome definitions, and recorded safety counts, but not a conclusion about the primary glycemic result, its precision, or a comparative treatment effect. The absence of reported outcome analyses is an evidence-reporting limitation, not a result that should be interpreted as no change or no effect.

13. Why This Trial Matters Statistically

This study raises a statistical question that is easy to obscure if outcome definitions are read as results. Its primary endpoint is defined in detail: it requires participants to meet both a low-glucose and a high-glucose time threshold. Yet the registry record does not report the percentage meeting that criterion. Separating a prespecified measurement definition from an observed estimate is essential to avoid treating a study question as a finding.

The single-group sequence also makes design language important. Baseline Open Loop use and subsequent AP use are distinct periods, but their ordering does not create a randomized comparison. General statistical interpretation must account for the difference between describing measurements over time and estimating a causal treatment effect. Without a parallel control group or a reported analysis addressing time-related differences, the latter is not established by the design information in the registry.

Precision matters alongside the point estimate. A percentage based on a small enrolled group can be uncertain, and an interval estimate would help show that uncertainty. The registry record does not report the primary estimate or its confidence interval. Therefore, neither the magnitude of the endpoint result nor its precision can be evaluated from the record.

The record also illustrates why outcome reporting and analysis documentation matter. It lists 15 outcome measures but zero analyses, and does not report missing-data handling, analysis populations, or multiplicity procedures. These omissions prevent readers from evaluating how the endpoint was calculated and how the collection of outcomes was addressed. They do not establish that the study handled these matters incorrectly; they mean that the registry record does not describe the methods.

Finally, the safety counts are interpretable as descriptive counts, not proof of zero risk. Clear denominators, observation windows, and event definitions are central to reading adverse event summaries. The record supplies a group at-risk count but little event detail. Statistically, the study matters as an example of how design, endpoint wording, reporting completeness, and uncertainty jointly determine what conclusions are justified.

14. 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 registry record does not report the primary endpoint result, secondary outcome results, confidence intervals, or inferential analyses. As a result, the primary glycemic question cannot be answered from the record, and the magnitude and precision of any outcome are unavailable. The record lists 15 outcome measures and zero analyses, but does not provide a statistical analysis plan.

The study enrolled 12 participants and had a single-group design. There is no randomized parallel control group described, and the baseline period preceded the Control-IQ period. This limits interpretation of any potential period-to-period contrast as a causal effect. The registry record does not report adjusted comparisons or analyses that account for the sequential timing and differing settings.

The observation periods are brief as described: baseline Open Loop results cover 2-7 day, with a median of 4 day, while AP results cover a 5 day admission that includes supervised hotel time and time at home. The record does not report longer-term follow-up results or separate outcome estimates for the hotel and home portions. Generalizability beyond the stated participants and observation context cannot be assessed from these data.

The primary outcome population, measurement completeness, missing-data handling, and analysis populations are not reported in the registry record. The sample-size justification and the trial’s own statistical plan are also not reported. The safety entry contains zero serious adverse events, zero other adverse events, and zero deaths among 12 at risk, but gives no serious event terms and does not specify a separate safety observation duration. These reporting gaps constrain interpretation; they do not establish that any particular bias or data problem occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety of Artificial Pancreas Therapy in Preschoolers, Age 2-6 — NCT04084171.
• Registry record last updated 2023-03-22; status last verified 2023-03.
• Results first posted 2023-03-22.
• 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.

18. Record Summary

NCT04084171 is a completed, single-group, multi-center study sponsored by the University of Virginia. It enrolled 12 children aged 2-6 years with type 1 diabetes to use Tandem t:slim X2 with Control-IQ Technology and Dexcom G6. The registry lists allocation as NA, masking as NONE, and phase as NA.

The primary endpoint is the percentage of subjects with less than 6% time below 70mg/dL and less than 40% time above 180mg/dL. Baseline Open Loop and AP observation periods are described, but the primary and secondary outcome results are not reported in the registry record. The record lists 15 outcome measures and zero analyses.

For the Artificial Pancreas Therapy group, the record reports 12 participants at risk, zero serious adverse events, zero other adverse events, and zero deaths. It does not report a statistical analysis plan, sample-size justification, missing-data approach, or analysis population. The registry supports description of the design and recorded safety counts, but not assessment of the primary outcome result or a causal treatment comparison.