Use of Continuous Glucose Sensors by Adolescents With Inadequate Diabetic Control: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Use of Continuous Glucose Sensors by Adolescents With Inadequate Diabetic Control (NCT00945659), a randomized na study. The primary outcome is Glycated Hemoglobin (HbA1c).

2. Clinical Question

3. Trial Design

The registry identifies NCT00945659 as a completed, randomized, parallel-group study sponsored by Nemours Children’s Clinic. Enrollment was 116. The study was not masked, and its phase is listed as NA. The registry records a start date of 2009-08 and primary completion on 2017-06-30. These design details describe how the trial was organized; they do not, by themselves, establish the size or direction of any treatment effect.

Participants were adolescents aged 11 to not yet 17 years with type 1 diabetes for at least 2 years and HbA1c above the stated target of 7.5%. They also had to have received established, consistent care at a Nemours Children’s Clinic location for at least 12 months before enrollment. The registry names locations in Wilmington, Philadelphia, Orlando, and Pensacola and says adolescents treated elsewhere were not eligible. This restriction is relevant when considering whether the enrolled population represents adolescents receiving care in other settings.

The parallel groups were Standard Care, Continuous Glucose Sensor, and CGS + Behavior Therapy. Standard Care consisted of intensified diabetes management with either an insulin pump or multiple daily injections using a basal-bolus approach. The sensor group retained the same diabetes management regimen and added a continuous glucose sensor, instruction, and clinical guidance. The behavior-therapy group received the sensor-group medical management and 6 scheduled therapist encounters designed to address barriers to sensor use. The registry record does not provide the full intervention descriptions in the available arm text.

Random assignment is intended, in general, to make groups comparable with respect to measured and unmeasured characteristics at the start of a trial. It does not guarantee that groups are identical, and the registry does not report details of the randomization sequence or allocation concealment. With no masking, participants and study staff knew the assigned care approach; the record does not describe whether outcome assessors were masked. The registry also does not report a statistical analysis plan, sample-size justification, or interim-analysis plan.

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:

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 Glycated Hemoglobin (HbA1c), measured over Baseline, 3, 6, 9 months.

The primary endpoint was glycated hemoglobin, or HbA1c, expressed as a percentage of hemoglobin molecules bound to glucose. In general, HbA1c is used as an indicator of glycemic control over time rather than as a reading of glucose at a single moment. It gives a continuous measure, so results can be described with a mean and a measure of variability. The registry specifies the mean and standard deviation, with assessments at baseline, 3, 6, and 9 months.

Repeated assessments can describe both the starting level and how the outcome changes during follow-up. Baseline values provide context for later measurements, while follow-up measurements can show whether group averages diverge, remain similar, or move in a similar pattern. A complete interpretation would consider the estimated differences between groups, their uncertainty, and the analysis used to account for repeated observations. Those numerical outcome results and analysis details are not reported in the registry record.

The record identifies the endpoint but does not reduce the multiple assessment times to one comparison. It therefore does not establish a particular primary contrast, such as a change from baseline at one visit or an average difference over follow-up. Nor does it provide group means, standard deviations, confidence intervals, or p-values for HbA1c. Without those results, the endpoint’s definition and measurement schedule can be described, but the magnitude and precision of any observed group differences cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, parallel-group design without masking. In general, randomization assigns participants to care groups by chance, helping to limit systematic differences at the start of a study. Its benefit depends on proper implementation, and chance imbalances can still occur. The record does not report the sequence-generation method or allocation concealment, so those implementation details cannot be evaluated. Parallel-group designs follow assigned groups over the study period rather than having each participant receive every approach in sequence.

What does a mean and standard deviation describe?

HbA1c is recorded as a continuous measure. The mean summarizes the central level in a group, whereas the standard deviation describes how dispersed individual measurements are around that average. The standard deviation is not the uncertainty of the mean: uncertainty in the estimated mean also depends on the amount of information and the analysis. The registry specifies a mean and standard deviation for the primary outcome, but numerical values are not reported in the registry record.

When comparing groups, an estimated difference in means can convey the size and direction of a contrast on the HbA1c scale. A confidence interval communicates the uncertainty around that estimate under the model and assumptions used. A narrow interval indicates greater precision than a wide interval, but an interval’s interpretation depends on the estimand, model, and analysis population. Neither a confidence interval nor a p-value is reported for the primary outcome in the registry record. Without the estimates, it is not possible to describe how precisely the groups’ HbA1c outcomes were compared.

Why do the repeated assessments matter?

Measurements at baseline, 3, 6, and 9 months create a longitudinal outcome structure. Measurements from the same participant are generally correlated, so a statistical analysis should account for that relationship if it uses multiple visits together. In general, an analysis may compare groups at a specified visit, compare changes from baseline, or estimate group patterns across visits. These are not interchangeable questions. The registry identifies the assessment schedule but does not report the primary contrast, the model, or how within-participant correlation was handled.

Missing measurements can also affect a longitudinal analysis. The consequences depend on how much information is missing, why it is missing, and the assumptions made by the analysis. Methods may use available observations under explicit assumptions or apply other approaches, but the registry does not report missing-data methods or the amount and pattern of missing primary-outcome data. No particular method should be attributed to this trial based on the outcome schedule alone.

How should planning illustrations be read?

The registry’s sample-size assumptions describe a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. They also describe the target effect as a stated fraction of the observed effect. Those are planning assumptions, not the trial’s reported analysis or a substitute for its results. The illustration is specified for a comparison between two arms, whereas the registered trial includes Standard Care, Continuous Glucose Sensor, and CGS + Behavior Therapy. It should not be taken to describe every possible comparison or the design justification for the whole trial.

A sample-size calculation estimates how many participants per arm might be needed under its assumptions to achieve a target power for a chosen effect and significance level. It is a prospective planning exercise. It is not observed power, and it does not establish that a result is meaningful or precise. The registry does not report a trial-specific sample-size justification, and numerical planning outputs are not included in the record details for this analysis. No planning count can therefore be stated.

What can be inferred from the reported design?

The trial’s unmasked status means participants and study staff knew the assigned approach. In general, lack of masking can influence expectations, behavior, co-interventions, or subjective outcome reporting. HbA1c is a laboratory-based continuous measure, but the record does not specify laboratory procedures or assessor masking. The record also does not report the analysis plan, whether analyses followed assignment regardless of adherence, or how protocol deviations were handled. Those details matter for assessing the robustness of comparisons and cannot be inferred solely from randomization and the parallel structure.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures and 26 analyses. The named secondary outcomes include adolescent and parent measures of diabetes technology, communication about blood glucose monitoring, family conflict, and family responsibility. In general, testing many outcomes or contrasts creates a multiplicity concern: even if each test uses a conventional threshold, the overall chance of a false-positive finding can increase when many tests are considered. Possible approaches include prespecifying a primary contrast, controlling an error rate, or interpreting secondary findings as exploratory. The registry record does not report whether any such approach was used.

HbA1c is identified as the primary outcome, with measurements at baseline, 3, 6, and 9 months. The record does not identify one primary time-point comparison or explain how the repeated observations were incorporated. It also does not report a hierarchy among secondary outcomes, which comparisons were prespecified, or whether analyses were adjusted for multiple testing. The listing of outcomes and analyses alone is not evidence that a particular adjustment was or was not applied.

Missing-data details are not reported in the registry record. The amount of missing outcome information, reasons for missingness, and methods for handling missing observations are not specified. Analysis populations are also not reported in the registry record; it is not possible to determine from these registry entries whether the primary analysis included everyone as randomized, only participants with available measurements, or another defined group. These omissions limit assessment of how exclusions, incomplete follow-up, or protocol deviations may have affected the estimates.

Randomization is most useful for interpretation when the analysis preserves the randomized comparison and clearly states how unavailable data are handled. That is a general methodological point, not a claim about the analysis conducted in this trial. The registry record does not provide enough detail to evaluate the analysis population, missing-data assumptions, or multiplicity strategy.

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 3% reporting threshold.

The registry lists serious and other adverse-event counts separately for each group. For Standard Care, 38 participants were listed as at risk for serious events and zero were affected; 38 were listed as at risk for other events and zero were affected. For Continuous Glucose Sensor, the corresponding figures were 39 at risk and zero affected for serious events, and 39 at risk and zero affected for other events. For CGS + Behavior Therapy, 35 were listed at risk for each category, with zero affected by serious events and zero affected by other events. Deaths are listed as zero in each group, and no serious adverse-event terms are listed.

These are the registry’s recorded counts, not proof that no adverse events occurred outside the reporting definitions or observation period. A zero count means that no affected participants were recorded for that category in the registry entry; it does not establish that the underlying risk is zero. The at-risk figures are the denominators shown for each group and category and should be read as reported rather than combined. The registry does not provide event descriptions, severity breakdowns, timing, or a safety comparison with uncertainty estimates. The counts therefore describe the posted safety record but do not support a broader conclusion about comparative safety.

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

The registry record gives a clear outline of the clinical question: among adolescents with type 1 diabetes and HbA1c above the stated target, the study compared Standard Care with adding continuous glucose sensor use, with or without behavior therapy. It also specifies HbA1c as the primary outcome and lists assessments at baseline, 3, 6, and 9 months. These design details help identify what the study was intended to examine.

They do not show what the primary outcome results were. Numerical HbA1c values, group comparisons, confidence intervals, and p-values are not reported in the registry record. Therefore, the record details do not establish whether HbA1c changed, whether the approaches differed, how large any difference might have been, or how precisely a difference was estimated. No conclusion that one approach was superior or equivalent to another can be drawn from the design description alone.

In general, statistical evidence has to be interpreted using both the estimated effect and its uncertainty. A small estimated difference may be measured precisely or imprecisely; a larger estimate may also be uncertain. Statistical significance, if reported, would not by itself describe clinical importance. For this trial, the numerical estimates needed to make those distinctions are not reported in the registry record.

The completed status and enrollment of 116 document the registry’s study status and enrollment figure, but neither substitutes for outcome reporting. Likewise, zero recorded adverse-event counts do not establish an absence of all harms or a comparative safety advantage. The listed counts should be understood as registry entries, with the limits of the reporting details noted.

The trial remains statistically informative as a study design: it examined sensor use and added behavioral support in a specific adolescent population, against a defined standard-care approach, with a continuous primary endpoint measured over follow-up. The extent to which its findings apply to adolescents treated outside the named clinic locations is also uncertain because eligibility required care at those locations. Any broader interpretation would need the outcome estimates, analysis methods, follow-up information, and participant characteristics, which are not reported in the registry record.

13. Why This Trial Matters Statistically

This study addresses a design question that is more specific than whether a device is used: it separates the addition of continuous glucose sensor use from sensor use combined with behavioral support. That distinction matters statistically because the groups represent different intervention packages. A comparison between the sensor arm and the behavior-therapy arm would address the additional support component, while comparisons with Standard Care would address broader differences in care. The registry identifies the arms but does not report numerical results for these contrasts.

The primary endpoint is continuous and measured repeatedly, offering a way to describe both average HbA1c levels and patterns over follow-up. Repeated measurements can add information, but the statistical question must be specified: a single-visit contrast, a change from baseline, and a group trajectory are different estimands. The registry lists the assessment schedule without reporting which of these was the primary contrast. That gap illustrates why an outcome name alone is not a complete statistical analysis specification.

The trial also includes outcomes involving adolescents and parents, technology experience, communication, and family processes. Such outcomes can illuminate dimensions of care beyond the primary glycemic measure, but a broad outcome set requires clear prespecification and careful interpretation. The registry records 13 outcome measures and 26 analyses; multiplicity methods and analysis priorities are not reported. This makes it important not to treat any isolated result as decisive without knowing how it fits the planned analysis.

Finally, the population was drawn from adolescents receiving established care at specified clinic locations and meeting defined eligibility criteria. This improves clarity about whom the research concerns while limiting assumptions about application to other settings. The registry’s outcome reporting limitations also show a central statistical lesson: a sound description of design does not replace effect estimates and their uncertainty. Without those results, the trial’s intended comparisons can be explained, but their empirical conclusions cannot be evaluated.

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 interpreting the trial from the registry record is the absence of numerical HbA1c results. The record identifies mean HbA1c, its standard deviation, and assessment times, but does not report values by group, estimated contrasts, confidence intervals, or p-values. It is therefore not possible to quantify observed differences or their precision.

The primary outcome spans baseline, 3, 6, and 9 months, yet the registry does not identify a single primary comparison or state how repeated measurements were analyzed. The statistical method, treatment of within-participant correlation, and handling of missing measurements are not reported. Analysis populations and the approach to protocol deviations are also not reported. These omissions prevent assessment of whether the reported analysis, if any, preserved the randomized comparison or relied on particular assumptions.

The registry lists 13 outcome measures and 26 analyses but does not report a multiplicity strategy, outcome hierarchy, or which secondary analyses were prespecified. This limits interpretation of multiple findings if encountered in other reporting. The record also does not report the trial-specific sample-size justification, randomization-sequence method, allocation concealment, or interim-analysis plan. The registry lists the study as unmasked but does not describe assessor masking.

Generalizability is bounded by the eligibility criteria: participants were adolescents aged 11 to not yet 17 years, with type 1 diabetes for at least 2 years and HbA1c above the stated target, and they had to receive established care at a Nemours Children’s Clinic location for at least 12 months. Adolescents treated elsewhere were ineligible according to the summary. The registry does not provide further participant characteristics or numerical outcome results that would allow assessment of how representative the enrolled population was. These limitations concern the information reported in the registry record and should not be mistaken for proof that the trial did not collect or analyze the missing information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Use of Continuous Glucose Sensors by Adolescents With Inadequate Diabetic Control — NCT00945659.
• Registry record last updated 2018-09-10; status last verified 2018-08.
• Results first posted 2018-09-10.
• 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

NCT00945659 is a completed randomized, parallel-group, unmasked study sponsored by Nemours Children’s Clinic, with enrollment of 116. It evaluated Standard Care, Continuous Glucose Sensor, and CGS + Behavior Therapy among adolescents with type 1 diabetes and inadequate glycemic control. The primary outcome was mean HbA1c, expressed as a percentage of hemoglobin molecules bound to glucose, assessed at baseline, 3, 6, and 9 months.

The registry also lists secondary measures related to diabetes technology, blood glucose monitoring communication, family conflict, and family responsibility. Serious adverse events, other adverse events, and deaths are recorded as zero affected in each group. Numerical primary-outcome results, analysis methods, missing-data handling, analysis populations, and multiplicity procedures are not reported in the registry record. The design and outcome definitions can be described, but the reported information does not establish the direction, magnitude, or precision of treatment-group differences.