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 Outpatient Control-to-Range: System and Monitoring Testing (NCT01578980), a na na study. The primary outcome is Percent Time of Active CTR.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01578980 |
| Phase | NA |
| Condition | Type 1 Diabetes Mellitus |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Virginia |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people with Type 1 Diabetes Mellitus. The registry record says three pilot subjects, one for each country, were not included in the analysis; it does not report the resulting analysis population size.
Intervention
The intervention is Outpatient Control-to-Range, described as testing system connectivity. The broader study summary describes use of the AP Platform, comprising a cell phone and Control to Range system, outside a hospital-based clinical research center.
Comparator
There is no concurrent comparator group. The study is described as single arm and single treatment, so it cannot provide a randomized, like-for-like contrast between treatments or systems.
Primary question
The primary endpoint asks what percentage of the investigation time had all expected CGM, pump, and patient manual-input data available on the Artificial Pancreas platform and monitoring stations. The stated success criterion was more than 80% of total investigation time for the entire arm, over 42 hours.
Statistically, this is a feasibility and connectivity question rather than a comparative efficacy question. The measure is intended to capture whether the expected streams of information were available together during outpatient system use. Its focus is the completeness and availability of data, not a clinical outcome or a comparison against another care approach.
The record also identifies the frequency of unplanned system resets or restarts as a secondary outcome. It does not report a result for that outcome. Nor does it report the observed primary endpoint value, so the available registry information cannot establish whether the stated success criterion was reached.
3. Trial Design
The trial is registered as NCT01578980, with the title “Outpatient Control-to-Range: System and Monitoring Testing.” It is marked completed. The registry lists a single-group model, no masking, and allocation as NA; the phase is also listed as NA. The planned enrollment is 20, and the condition is Type 1 Diabetes Mellitus.
The study description calls it a single-arm, single-treatment study to assess feasibility of the AP Platform outside a hospital-based clinical research center. The intervention is a device named Outpatient Control-to-Range. Its arm description specifies testing system connectivity. The trial therefore evaluates one system in one study group rather than assigning participants to competing interventions.
The registry lists the study start as 2012-04 and primary completion as 2012-06. The primary outcome timeframe is 42 hours. Its measurement is the percentage of time when all expected data from CGM, the pump, and patient manual inputs should be available on the Artificial Pancreas platform and monitoring stations.
The record describes a success threshold of more than 80% of total investigation time for the entire arm. It does not report a protocol-level explanation of how that threshold was selected. The record also says three pilot subjects, one for each country, were not included in the analysis. It does not identify the analysis denominator, so the number enrolled should not be treated as the number contributing to the primary endpoint.
The registry lists two outcome measures and no analyses. It supplies a primary endpoint description and names frequency of unplanned system resets or restarts as a secondary outcome, but does not report numerical outcome results. Sample-size justification, interim analyses, and a detailed statistical analysis plan are 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.
Overall Study
| Stage | Outpatient Control-to-Range |
|---|---|
| STARTED | 20 |
| COMPLETED | 20 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: The three pilot subjects (one for each country) were not included in the 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.
| Characteristic | Unit | Outpatient Control-to-Range |
|---|---|---|
| Participants analysed | 20 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 12 |
| Sex: Female, Male: Male | Participants | 8 |
| Region of Enrollment: United States | participants | 10 |
| Region of Enrollment: France | participants | 5 |
| Region of Enrollment: Italy | participants | 5 |
| HbA1c 6-9% | participants | 20 |
6. Primary Endpoint
The registry lists the primary outcome as Percent Time of Active CTR, measured over 42 hours.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of time of active CTR |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percent time of active Control-to-Range, expressed as a percentage of time of active CTR. The description defines the relevant time as time when all expected data from CGM, the pump, and patient manual inputs are available on the Artificial Pancreas platform and monitoring stations. The stated observation timeframe is 42 hours.
This endpoint is designed to represent system and monitoring connectivity during outpatient use. Requiring all expected data streams to be available makes the measure a joint completeness criterion: availability of only some streams would not meet the endpoint’s stated definition. The endpoint therefore addresses operational feasibility of the platform rather than a patient health outcome.
The registry sets success as more than 80% of total investigation time for the entire arm. This threshold gives the feasibility question a prespecified-looking benchmark in the outcome description, but the registry record does not explain its rationale or report the observed percentage. It is therefore not possible to determine from the record whether the threshold was met.
The endpoint description does not specify how missing or invalid data intervals were handled, how the time percentage was calculated in practice, or how variability across participants was summarized. Those details are not reported in the registry record. The secondary outcome, frequency of unplanned system resets or restarts, addresses another aspect of system operation, but no result for it is reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives the intended primary measure and its success threshold, but it does not give an observed primary endpoint value. It also lists no analyses. As a result, the central feasibility question cannot be answered from the posted registry information: the reader cannot tell whether all expected data were available for more than 80% of the investigation time.
The study design also limits what an observed percentage could establish. A single-group study can describe system performance in the studied setting, but without a concurrent comparator it cannot estimate a comparative effect against another system or approach. No randomized comparison is described, and the record itself flags the absence of a like-for-like control comparison.
The endpoint is a measure of data availability, not a direct measure of clinical benefit or harm. Even if an observed availability result were reported, it would answer only the defined connectivity question under the study conditions. It would not by itself establish performance in other settings, for other durations, or in populations not represented by the study.
The outcome description sets a threshold of more than 80% of total investigation time for the entire arm. The registry does not report a result against that benchmark, a confidence interval, or a participant-level distribution. Without those statistics, there is no reported estimate of precision and no way to assess whether an arm-level percentage might conceal variation across participants.
The record reports a planned enrollment of 20 and says three pilot subjects were excluded from analysis. It does not state the actual analysis denominator. Those details should not be combined to infer a denominator, because the record does not clarify how the pilot subjects relate to the enrollment figure or identify the number included in the primary analysis.
The registry reports serious adverse event counts, along with percentages for listed serious event terms, but these figures do not substitute for the missing primary endpoint result. They describe safety reporting and should be read separately from the connectivity measure. The registry does not report causal attribution, detailed event timing, or a comparative safety assessment.
Overall, the record establishes the study’s purpose, design, endpoint definition, and some safety counts. It does not provide the outcome results needed to judge whether the stated connectivity benchmark was attained. Conclusions about the observed feasibility performance, its precision, or comparative performance are not reported in the registry record.
9. Statistical Methods Explained
What kind of estimate was intended?
The primary endpoint is an arm-level percentage of investigation time satisfying a completeness condition. For each relevant time interval, the condition concerns availability of all expected CGM, pump, and patient manual-input data on the platform and monitoring stations. The endpoint description then expresses qualifying time as a percentage of total investigation time. This is a descriptive feasibility measure; the registry does not describe a treatment-effect contrast for it.
As a general statistical explanation, a percentage estimate summarizes the share of observed time meeting a stated condition. Its interpretation depends on defining the time intervals, handling gaps, and specifying the denominator consistently. Those operational details matter because different rules for incomplete data could change the estimate. The registry record describes the intended data streams and the 42-hour timeframe, but does not report interval-level rules or the calculation procedure.
What does the success threshold mean?
The outcome description states that success requires more than 80% of total investigation time for the entire arm. This is a benchmark for the planned endpoint, not a reported result. The registry record does not explain how the benchmark was selected, nor does it report an observed percentage against which to assess it. A threshold alone cannot establish whether the study met its feasibility goal.
As a general statistical explanation, a point estimate is more informative when accompanied by an interval expressing uncertainty. A confidence interval describes a range of values compatible with the data and the statistical assumptions used. It is not reported for this endpoint. The absence of an interval means the precision of any primary estimate cannot be assessed from the registry record.
Why does the single-group design matter?
The trial is listed as single group, with allocation NA and no masking. It has no concurrent control arm. As a general principle, an uncontrolled study can describe measurements made in its participants but cannot separate the system’s performance from other influences by contrasting outcomes across randomized groups. The record does not describe a comparative analysis, and its stated feasibility objective is consistent with a descriptive rather than comparative question.
The statistical assumptions for planning illustrations describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. These are planning assumptions, not a description of the single-group trial design. Planning illustrations are not observed power, and they should not be interpreted as the study’s original design or as evidence that an outcome was attained. The registry record does not report a sample-size justification for the trial itself.
How should the outcome structure be read?
The registry lists two outcome measures and no analyses. The primary measure is a percentage-time endpoint; the secondary measure is frequency of unplanned system resets or restarts. The outcome classification is count/other and is not reduced to one comparison. The record does not specify an inferential model, a confidence-interval method, an adjustment strategy, or a procedure for testing the secondary outcome. These details are not reported in the registry record.
As a general explanation, over-dispersion matters when count data vary more than a simple count model assumes. If such a model is used, underestimating variability can make uncertainty appear too small. The registry names a frequency outcome but provides no count result, model, or assessment of dispersion. It is therefore not possible to say whether over-dispersion was relevant to the secondary analysis or how it was handled.
What does the analysis exclusion imply?
The primary endpoint description says three pilot subjects, one for each country, were not included in the analysis. It does not state the resulting analysis population size or give a participant flow. A sample-size denominator cannot be recovered by subtracting the pilot subjects from planned enrollment, because the record does not establish how these groups relate. As a general principle, defining the analysis population matters because estimates depend on which participants and observations contribute data.
The registry record does not explain how missing time intervals, incomplete streams, participant withdrawals, or unusable monitoring data were treated. Missing data handling can affect a time-availability estimate, particularly when the endpoint itself concerns whether expected data were present. Without the analysis rules and observed results, neither the effect of missingness nor the precision of the endpoint estimate can be assessed.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures: the primary percent-time endpoint and the secondary frequency of unplanned system resets or restarts. It does not report an analysis for either outcome. The record does not state whether the outcomes were tested formally, whether any adjustment for multiple testing was planned, or whether the secondary outcome was considered descriptive. Those procedures are not reported in the registry record.
As a general statistical explanation, multiplicity arises when several outcomes or comparisons are examined. Repeated testing can increase the chance of an apparently noteworthy finding by chance, so a statistical plan often specifies which outcome is primary and how other tests will be interpreted. Here, the primary outcome is identified, but a detailed testing hierarchy or multiplicity strategy is not reported. No inference about statistical significance can be made from the outcome descriptions alone.
The record says three pilot subjects were not included in the analysis, but does not report the analysis population size or explain how that exclusion was applied. It also does not describe how missing or incomplete CGM, pump, or manual-input data were handled. This is particularly relevant because the primary endpoint depends on data availability. Whether missing intervals count as unavailable, are omitted, or are handled by another rule is not reported in the registry record.
The registry does not report a participant flow, a primary endpoint estimate, a confidence interval, or an analysis dataset description. These omissions prevent assessment of the analysis denominator, missing-data impact, and precision. They also mean that no adjustment or sensitivity analysis can be verified from the registry record.
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 |
|---|---|---|---|
| Outpatient Control-to-Range | 9 | 20 | 45.0% |
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 |
|---|---|
| Outpatient Control-to-Range | 0 of 20 |
Most frequent serious adverse event terms
| Event term | Organ system | Outpatient Control-to-Range |
|---|---|---|
| Hypoglycemia | Endocrine disorders | 6 of 20 |
| Staff Initiated System Shut-dowm | Endocrine disorders | 3 of 20 |
Serious events with the highest arm-level rate: hypoglycemia (30.0%), staff initiated system shut-dowm (15.0%).
The registry lists serious adverse events for the Outpatient Control-to-Range group, with 20 at risk and 9 affected. It also lists 20 at risk and 0 affected for other adverse events. These are reported counts; the registry does not provide event-level details or explain whether multiple events could have occurred in an individual.
The listed serious adverse event terms include Hypoglycemia at 30.0% and Staff Initiated System Shut-dowm at 15.0%. These percentages are reported as registry terms. The record does not give the underlying event counts for those terms or clarify their denominator, so the percentages should not be converted into counts or interpreted as participant-level risks.
Deaths are not reported in the registry record. A missing death entry should not be read as a reported count of zero. The record also does not report causal attribution, severity beyond the serious-event category, timing, or a comparison group. These figures therefore describe the registry’s safety entries, not a comparative estimate of risk or a conclusion about whether the device caused an event.
12. What the Result Does, and Does Not, Mean
The record documents a completed, single-group study designed to assess outpatient feasibility of the AP Platform and system connectivity. It defines a primary endpoint based on the percentage of time that all expected CGM, pump, and patient manual-input data were available, and it states a success benchmark of more than 80% of total investigation time for the entire arm.
However, the registry does not report the observed primary endpoint result. It therefore does not establish whether the benchmark was reached, how far the observed measure was from the benchmark, or how precisely the endpoint was estimated. The secondary outcome is named, but its result is also not reported. The record lists no analyses.
The study’s single-group design further limits interpretation. Even with a reported connectivity estimate, the record would not support a randomized comparison with another system or intervention. A descriptive result would apply to the conditions and participants studied; the registry does not provide evidence for generalization beyond that setting.
The planned enrollment is 20, while the endpoint description says three pilot subjects were excluded from analysis. Because the record does not report the analysis denominator, these figures do not establish how many participants contributed to the primary endpoint. Nor does the record describe missing-data handling or provide participant-level results.
Safety entries report serious adverse events and other adverse events, but they do not supply causal assessments or comparative safety evidence. Thus, the record supports a description of the study’s purpose, design, endpoint definition, and reported safety counts. It does not support a conclusion about observed connectivity performance, statistical precision, comparative performance, or clinical benefit.
13. Why This Trial Matters Statistically
This trial illustrates why a feasibility endpoint needs both a clear operational definition and an observed result. The registry identifies the data streams that must be available together and sets a percentage-time benchmark. That framing makes the intended question understandable: whether the monitoring system could maintain the required data availability during outpatient use.
At the same time, the registry record does not report the endpoint estimate, its precision, or an analysis denominator. Without those elements, the reader cannot judge whether the feasibility benchmark was met or how stable an estimate might be. The distinction between describing an intended measure and reporting its observed value is essential when interpreting registry information.
The study also highlights a design distinction. A single-group feasibility study can address whether a system was evaluated under a specified setting, but it is not a like-for-like comparison. The record lists no comparator and does not report a treatment-effect analysis. Any interpretation should therefore remain descriptive rather than comparative.
The exclusion of three pilot subjects from the analysis also underscores the importance of defining analysis populations. The record does not state the final denominator, so planned enrollment cannot be assumed to equal the population used for the endpoint. In a data-availability study, explicit rules for incomplete streams and missing intervals are especially important, yet those rules are not reported.
Finally, the safety entries and connectivity endpoint answer different questions. Serious adverse event counts do not establish whether the platform maintained data connectivity, and a connectivity measure does not establish a safety effect. Keeping these outcomes separate helps prevent claims that extend beyond what the registry record reports.
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 primary limitation for interpretation is that no observed primary endpoint result is reported. Although the endpoint definition and success threshold are stated, the registry provides no estimate showing the percentage of investigation time meeting the data-availability condition. It also reports no confidence interval or other measure of precision.
The record lists no analyses and does not report the denominator used for the primary endpoint. It says three pilot subjects were excluded from analysis, but does not report the final analysis population or clarify how that exclusion relates to planned enrollment of 20. Missing-data rules for incomplete or unavailable system streams are not reported, despite their direct relevance to the endpoint.
The single-group design has no concurrent comparator, and masking is listed as none. This means the record does not provide a controlled comparison of system performance. The study’s stated focus is feasibility and connectivity, so it should not be interpreted as a comparative evaluation.
The endpoint description does not report how time intervals were defined or how the percentage was calculated in practice. The rationale for the more-than-80% benchmark is not reported. The registry also does not report a result for the secondary frequency of unplanned system resets or restarts.
For safety, the record gives aggregate affected counts and percentages for listed serious event terms, but not event-level details, causal attribution, timing, or a comparator. Deaths are not reported in the registry record. These limitations prevent a fuller assessment of safety patterns or their relationship to the intervention.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Outpatient Control-to-Range: System and Monitoring Testing — NCT01578980.
- Registry record last updated 2014-09-16; status last verified 2014-08.
- Results first posted 2014-08-25.
- 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
NCT01578980 is a completed, single-group, unmasked device study titled “Outpatient Control-to-Range: System and Monitoring Testing,” sponsored by the University of Virginia. The registry lists Type 1 Diabetes Mellitus as the condition, planned enrollment of 20, a start of 2012-04, and primary completion in 2012-06.
The study aimed to assess feasibility of the AP Platform outside a hospital-based clinical research center. Its primary endpoint measures the percentage of time all expected CGM, pump, and patient manual-input data were available during a 42-hour timeframe. The stated success criterion is more than 80% of total investigation time for the entire arm. Three pilot subjects were not included in the analysis.
The registry lists frequency of unplanned system resets or restarts as a secondary outcome, two outcome measures, and no analyses. It reports serious and other adverse-event counts but no primary or secondary outcome results. The observed connectivity performance and its precision are therefore not reported in the registry record.