This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The Bio-Inspired Artificial Pancreas for the Home (NCT03740698), a randomized na study. The primary outcome is % Time in Target Range Defined as 3.9-10mmol/l.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03740698 |
| Phase | NA |
| Condition | Diabetes Mellitus, Type 1 |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Imperial College London |
| Results posted | Yes |
2. Clinical Question
Population
People with type 1 diabetes. The registry describes the preliminary analysis as involving 2 participants, with only two weeks of data available.
Intervention
The Bio-Inspired Artificial Pancreas (BiAP), described in the arms as a closed-loop system with either a fixed bolus calculator or the Advanced Bolus Calculator for Diabetes (ABC4D).
Comparator
Sensor augmented pump (SAP), described as an open-loop combination of an insulin pump and continuous glucose monitoring. The registry lists 0.0 participants in this arm.
Primary question
What percentage of time was interstitial glucose within the target range of 3.9-10mmol/l during the available preliminary data for the BiAP arms?
The study record frames the project as an evaluation of the safety and effectiveness of a closed-loop insulin delivery system. Its stated components are a glucose sensor, a control algorithm that calculates an insulin dose, and an insulin pump that delivers the calculated insulin. The sensor is described as measuring glucose every 5 minutes.
The primary endpoint is percentage of time in the target glucose range. Posted values are 70.0 for BiAP with the fixed bolus calculator and 77.0 for BiAP with ABC4D. Those are descriptive arm results from the limited available data, not a complete randomized comparison. The registry lists no participants in the SAP open-loop arm, and it describes the analysis as preliminary. It therefore does not support a comparison of all three study arms or a conclusion about the comparative effect of BiAP and SAP.
3. Trial Design
The registry describes a randomized, unmasked crossover study. It lists the study as terminated, with a recorded enrollment of 8. The record gives a start date of 2021-02-01 and a primary completion date of 2022-01-31. The reason for termination is not reported in the registry record.
Three arms are described: SAP open-loop, BiAP with a fixed bolus calculator, and BiAP with ABC4D. The SAP arm is described as a sensor augmented pump combining an insulin pump and continuous glucose monitoring. The two BiAP arms are described as closed-loop systems, with the calculator approach distinguishing them. The listed interventions are BiAP and ABC4D.
A crossover design generally assigns participants to receive more than one study condition, so observations within a participant may contribute to comparisons. That structure depends on the actual treatment sequences, periods, and availability of measurements. The sequence and period details are not reported in the registry record. Neither are details of any washout or carryover assessment, so no assumptions about these features are warranted.
The registry states that the original plan was to measure interstitial glucose by continuous glucose monitoring over six months. It also states that the study was terminated early and that only two participants entered the allocated study arm and remained in the study for two weeks. The primary outcome description characterizes the available material as two weeks of data for preliminary analysis. It does not report how the recorded enrollment of 8 relates to those who entered the allocated arm or to the available endpoint data. The participant flow beyond these statements is not reported in the registry record.
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: This study was put on hold after two participants completed two weeks of the intervention (BIAP) due to technical issues. Due to multiple factors this study has not restarted since and a decision has been made to terminate it.
Overall Study
| Stage | SAP, Open-loop | BiAP, Fixed Bolus Calculator | BiAP, ABC4D |
|---|---|---|---|
| STARTED | 0 | 1 | 1 |
| COMPLETED | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 1 | 1 |
Reasons for not completing this period:
| Reason | SAP, Open-loop | BiAP, Fixed Bolus Calculator | BiAP, ABC4D |
|---|---|---|---|
| Physician Decision | 0 | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: 2 participants with type 1 diabetes. Only two weeks worth of data available for preliminary analysis.
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: Only two of the 8 participants screened and deemed eligible entered an intervention arm. The study was terminate dearly.
| Characteristic | Unit | SAP, Open-loop | BiAP, Fixed Bolus Calculator | BiAP, ABC4D | Total |
|---|---|---|---|---|---|
| Participants analysed | 0 | 1 | 1 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 1 | 1 | 2 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 0 | 1 | 1 | 2 |
| Race and Ethnicity Not Collected | Participants | — | — | — | 0 |
| Region of Enrollment: United Kingdom | Participants | 0 | 1 | 1 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as % Time in Target Range Defined as 3.9-10mmol/l, measured over 6 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of time spent in target |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is percentage of time spent in the target range, defined as 3.9-10mmol/l. It uses interstitial glucose measurements collected by continuous glucose monitoring. The registry describes measurements every 5 minutes and identifies six months as the original measurement timeframe. The record also says the study ended early and only two weeks of data were available for preliminary analysis.
Time in range expresses how much of the monitored time glucose readings fall within a prespecified interval. In general, this can summarize many repeated measurements in a way that is more informative about the distribution of glucose over time than a single measurement. It is a descriptive endpoint: by itself, it does not show why readings were in or out of range, nor does it establish a causal difference between study conditions.
The posted values are 70.0 for BiAP with the fixed bolus calculator and 77.0 for BiAP with ABC4D. The registry does not report a value for the SAP open-loop arm. It also does not state a separate analysis population or a more detailed method for deriving the percentages from the glucose readings. The available outcome description therefore supports a limited account of time in range in the two BiAP arms, not a complete assessment over the original timeframe.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary endpoint values reported are 70.0 for BiAP with a fixed bolus calculator and 77.0 for BiAP with ABC4D. Each arm has a listed participant count of 1.0. The SAP open-loop arm has a listed participant count of 0.0 and no endpoint value. The registry describes only two weeks of data as available for preliminary analysis, although the original plan was to collect six months of measurements.
These figures describe the posted arm results; they do not establish a reliable comparative effect. With one participant listed in each BiAP arm and no reported SAP result, the data cannot provide a balanced comparison of the three named approaches. The registry record does not report uncertainty estimates for the endpoint values, such as confidence intervals. Without uncertainty estimates and a suitably informative comparison, the precision of any difference between approaches cannot be assessed. The two values should not be read as evidence that one approach is superior.
The crossover designation matters because the intended comparison may have depended on repeated observations within participants across study conditions. The registry does not give treatment sequences, period-specific results, or details of how any within-participant structure was handled. It is therefore not possible to determine from the record whether the posted arm values are paired comparisons, period summaries, or another form of summary. The record also does not report an inferential analysis; it lists no analyses.
The early termination and short available observation period limit what these endpoint results can establish. The six-month timeframe describes the original plan, not the data available for the preliminary analysis. A short observation period does not represent the full planned duration, and the record does not explain whether the available measurements capture typical patterns over time. It also does not provide the reason for termination.
Accordingly, the posted data are best understood as preliminary descriptive results from the two BiAP arms. They do not answer a complete comparative-effectiveness question, quantify uncertainty, or establish how the results would generalize beyond the observed participants and period. The registry does not report a sponsor analysis of a comparison that could resolve those limitations.
9. Statistical Methods Explained
The registry identifies the study as randomized, unmasked, and crossover. Randomization is a method for assigning study conditions in a way intended to reduce systematic differences between groups or treatment sequences. In general, randomization does not guarantee balance in a small study, and it cannot compensate for an arm with no endpoint data. The sequence-generation procedure and allocation details are not reported in the registry record.
In a crossover study, participants generally receive multiple conditions, and comparisons can use measurements from the same participant under each condition. In general, that can reduce the influence of stable differences between participants. It also makes the treatment sequence and timing of measurements important. If an effect carries from one period into another, comparisons may be affected; study design and analysis ordinarily need to account for this possibility. The registry does not report the treatment sequences, periods, washout arrangements, or any assessment of carryover. It also does not describe the statistical method used to account for repeated observations.
What can the endpoint values tell us?
The endpoint is percentage of time in the 3.9-10mmol/l target range, based on interstitial glucose measurements. The two posted BiAP values are 70.0 and 77.0. These are descriptive summaries. A summary value alone does not show the spread of readings around it, how consistently the target was reached over time, or how much the value might vary under repeated measurement. No measure of dispersion or confidence interval is reported for these outcomes.
In general, a confidence interval describes a range of values compatible with the data and the assumptions of the analysis. It helps readers judge precision, rather than indicating that a result is certain or that a particular effect is established. No confidence interval is reported in the registry record, and the available data are too limited to infer one from the posted summaries without making additional assumptions. No such calculation is presented.
Why is there no full arm comparison?
The registry lists 0.0 participants for SAP open-loop and gives no endpoint result for that arm. It lists 1.0 participant in each BiAP arm. The posted summaries therefore do not contain outcome data across all three named conditions. The registry also lists no analyses. A formal comparative analysis, including the method and its assumptions, is not reported in the registry record.
In general, over-dispersion means that observed variability is greater than a statistical model expects. It can make standard errors too small if a model assumes less variability than is actually present. Repeated glucose observations can have patterns and correlations over time, so treating every measurement as independent would generally be inappropriate. The registry does not describe any model for repeated measures, correlation over time, or over-dispersion. This is a general statistical consideration, not a claim about an analysis performed in this study.
How should planning illustrations be read?
Any sample-size calculations associated with these results are planning illustrations based on the observed effect, not the trial's original design or observed power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. The registry does not report a sample-size justification for the trial. With preliminary summaries from one participant in each BiAP arm and no SAP outcome, such illustrations should not be interpreted as evidence about the study's power or as a substitute for a prespecified design.
More broadly, the registry does not report an analysis plan, a model for the primary endpoint, handling of repeated observations, adjustment variables, or inferential tests. These details matter for interpreting estimates and uncertainty, particularly in a crossover study with limited available data. General explanations of those methods do not establish which methods were used in this trial.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no secondary outcomes. It lists no analyses. A statistical analysis plan, including any prespecified hypotheses, testing hierarchy, or multiplicity adjustment, is not reported in the registry record. With no reported analysis plan or inferential results, the record does not show how multiple comparisons or repeated looks at the data were addressed, if applicable.
Missing data are especially relevant because the original outcome timeframe was six months, while the registry says only two weeks of data were available for preliminary analysis after early termination. The SAP arm has no listed endpoint value, and the two BiAP arms each have a listed participant count of 1.0. The record does not explain why the SAP value is absent, how much measurement data were missing within the available period, or whether any readings were excluded. No imputation method or other missing-data procedure is reported.
The record also does not identify a defined analysis population, such as an intention-to-treat or per-protocol population. It does not describe how participants who did not enter or remain in an allocated arm were handled. The enrollment figure and the account of the two participants with preliminary data do not provide a full participant flow. These gaps prevent assessment of whether the available outcome summaries represent all participants according to a prespecified analysis rule.
In general, missingness can affect an estimate when the availability of measurements is related to the outcome or to study condition. The direction and size of such an effect cannot be inferred from this record. The absence of detail does not establish that a particular bias occurred, but it limits assessment of the endpoint summaries and their applicability to the originally planned six-month period.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| BiAP, Fixed Bolus Calculator | 0 | 1 | 0.0% |
| BiAP, ABC4D | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| SAP, Open-loop | 0 of 0 |
| BiAP, Fixed Bolus Calculator | 0 of 1 |
| BiAP, ABC4D | 0 of 1 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| SAP, Open-loop | 0 of 0 |
| BiAP, Fixed Bolus Calculator | 0 of 1 |
| BiAP, ABC4D | 0 of 1 |
The registry reports safety figures separately for the listed arms. For BiAP with the fixed bolus calculator and BiAP with ABC4D, 1 participant is listed as at risk for serious adverse events in each arm, with 0 serious events reported in each. The same arms each list 1 participant at risk for other adverse events and 0 other adverse events. Neither arm lists a death.
The SAP open-loop arm lists 0 participants at risk for serious adverse events and 0 at risk for other adverse events; it also lists 0 events and 0 deaths. Because no participant is listed at risk in that arm, its zero event counts should not be interpreted as evidence about safety under SAP. The arm has no reported exposure in these safety figures.
These counts are very limited and should be read as the registry's recorded event figures, not as a precise estimate of risk. In general, observing no events among a very small number of participants does not rule out events in a larger population or during longer observation. The study was terminated early, and the registry describes only two weeks of available study data for preliminary analysis. It does not report additional detail about event definitions, monitoring duration by participant, or reasons for termination.
12. What the Result Does, and Does Not, Mean
The posted results establish that the registry contains preliminary time-in-target-range values for two BiAP arms: 70.0 for the fixed bolus calculator and 77.0 for ABC4D. They also establish that the record lists 1.0 participant in each of those arms and 0.0 in the SAP open-loop arm. The endpoint description says that only two weeks of data were available for preliminary analysis, rather than the original six-month measurement period.
Those details do not establish a comparative treatment effect. There is no endpoint value for SAP, no reported inferential analysis, and no uncertainty estimate for either BiAP value. The recorded values should not be treated as proof that one BiAP configuration performs better than another, nor as evidence about the difference between either BiAP configuration and SAP. A numerical contrast between the posted values would not resolve the limitations created by the very small amount of participant-level information and the missing SAP outcome.
The results also do not describe a complete account of outcomes across the planned study duration. The registry does not report why the study ended early, how the recorded enrollment relates to the two participants in the preliminary analysis, or what happened to the remaining enrolled participants. It does not report the details needed to assess the representativeness of the available glucose data or how the crossover structure was analyzed.
In general, a registry result is one part of an evidence record. The meaning of a study estimate depends on its design, data completeness, analysis methods, and uncertainty. Those considerations are particularly important because the record describes preliminary observations, not a completed six-month endpoint analysis. The posted data can be read as limited descriptive observations, but they cannot establish how the system would perform over the original timeframe or in a broader group.
13. Why This Trial Matters Statistically
This trial is statistically notable because it combines a crossover design with early termination and very limited available outcome data. A crossover design can be useful for comparing conditions within participants, but interpretation depends on the sequence of conditions, timing, completeness of repeated measurements, and handling of possible carryover. Those design and analysis details are not reported in the registry record.
The outcome itself is based on repeated glucose measurements: the study description refers to measurements every 5 minutes, while the original plan was to collect data over six months. The available preliminary analysis instead covers two weeks. In general, repeated measurements contain information about patterns over time, but observations close together may be correlated. Analyses need to account for that structure when estimating uncertainty. The registry does not report a method for doing so.
The contrast between the planned timeframe and the preliminary data also illustrates why an endpoint value and its precision are different things. A percentage can be reported even when the amount of data is insufficient to support a reliable comparative estimate. No uncertainty interval or inferential result is reported, and the open-loop comparator has no listed endpoint value.
For researchers, the record highlights the importance of documenting participant flow, analysis populations, missing-data handling, and prespecified methods when a trial ends before its planned duration. Without these details, even clearly reported descriptive values may be difficult to interpret as evidence about differences between study conditions. The record's figures are useful as a transparent account of what was posted, but their statistical scope remains narrow.
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 most direct limitation is the gap between the original six-month monitoring plan and the two weeks of data described as available for preliminary analysis. The registry does not report why the study was terminated early or whether the short observation period was expected to capture the endpoint adequately.
The endpoint data are sparse: the record lists 1.0 participant for each BiAP arm and no participant in the SAP arm. No SAP endpoint value is reported. This precludes a complete comparison across the three described study conditions. The record does not explain how the recorded enrollment of 8 relates to those who entered the allocated arm, remained in the study, or contributed data.
Important design and analysis details are also absent. Treatment order, period-specific outcomes, handling of repeated measurements, crossover carryover assessment, analysis population, missing-data approach, and statistical model are not reported in the registry record. There are no reported confidence intervals or inferential analyses. Consequently, precision and the robustness of the descriptive endpoint values cannot be evaluated from the posted information.
The safety figures are likewise limited by the small at-risk counts and the short available observation. The record does not provide additional context about monitoring duration or event ascertainment. These limitations do not show that the reported values are incorrect; they define what can and cannot be concluded from the record. The reason for termination and details of participant flow are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Bio-Inspired Artificial Pancreas for the Home — NCT03740698.
- Registry record last updated 2024-02-05; status last verified 2023-05.
- Results first posted 2024-02-05.
- 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.
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18. Record Summary
The Bio-Inspired Artificial Pancreas for the Home is recorded as a randomized, unmasked crossover study of people with type 1 diabetes. Its status is terminated. The record lists enrollment of 8, a start date of 2021-02-01, and a primary completion date of 2022-01-31.
The primary endpoint is percentage of time in the 3.9-10mmol/l target range. The original plan described six months of continuous glucose monitoring, with glucose measured every 5 minutes. The registry states that only two participants entered the allocated study arm and remained in the study for two weeks, and that only two weeks of data were available for preliminary analysis.
Endpoint values are reported for the BiAP fixed bolus calculator arm and the BiAP ABC4D arm; the SAP open-loop arm has no listed outcome value. The registry reports no analyses and no secondary outcomes. The reason for early termination, detailed participant flow, and statistical analysis plan are not reported in the registry record.