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 Adjusting Insulin Delivery to Activity (NCT02299479), a na na study. The primary outcome is Change From Baseline in Supplemental Carbohydrate Interventions up to 3 Months From Baseline..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02299479 |
| Phase | NA |
| Condition | Diabetes, Nocturnal Hypoglycemia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Children's Hospital |
| Results posted | Yes |
2. Clinical Question
Population
Children and adolescents with type 1 diabetes managed with insulin pump therapy. The study description planned to enroll participants in two age groups: 1 to <7 years old and 7 to 17 years old. Registry enrollment is 20.
Intervention
Participants wore a Dexcom G4 Platinum continuous glucose monitor and an activity monitor. Investigators were to review activity monitor, glucose monitor, and insulin pump data and make recommendations about nighttime basal insulin adjustments.
Comparator
The primary measure compares each participant’s supplemental carbohydrate interventions during the study period with that participant’s baseline period. There is no separate control group or randomized comparison in the registry record.
Primary question
How did the median number of supplemental carbohydrate interventions used to prevent hypoglycemia change from baseline during follow-up of up to 3 months?
The study addresses the relationship between daytime activity and overnight glucose management. Its description notes that increased daytime activity is associated with overnight hypoglycemia and proposes using activity monitor data, alongside continuous glucose monitor and insulin pump data, to guide recommendations for nighttime basal rates. The primary outcome focuses on supplemental carbohydrate interventions, a behavioral response used to prevent hypoglycemia, rather than reporting a direct treatment-versus-control contrast.
Secondary questions named in the registry record concern the correlation between daytime activity and nighttime nadir glucose, and change from baseline in supplemental carbohydrate interventions among subjects with an activity effect. The record does not report results for these questions. It also does not report a numerical result for the primary question, so the direction and size of any change cannot be assessed from the posted record.
3. Trial Design
This is a completed, single-group study sponsored by Boston Children's Hospital. The registry record lists enrollment as 20, masking as none, and allocation as NA. It does not describe a randomized comparison. The study dates are recorded as starting in 2015-07, with primary completion on 2017-06-27. The phase is listed as NA.
Participants were to wear a Dexcom G4 Platinum continuous glucose monitor and an activity monitor. The study description says that data would be uploaded to investigators regularly, and that recommendations for insulin-dose adjustments would be based on analysis of those data. The brief description specifies an initial two-week period to establish activity baselines, followed by nighttime basal insulin recommendations based on activity monitor, glucose monitor, and insulin pump data. The planned monitoring period is described as up to 3 months.
The primary comparison is within participants: each participant’s supplemental carbohydrate interventions during the study period are compared with that participant’s baseline period. This design can describe change over time in the enrolled group, but it does not provide a concurrent untreated group for separating the intervention’s contribution from other changes over time. The registry record does not report details of adherence, the actual number of completed monitoring days, or how recommendations were implemented.
The age groups described are 1 to <7 years old and 7 to 17 years old, with 10 subjects planned in each group in the study description. The registry record does not report whether enrollment or follow-up differed between those age groups. It also does not report a sample-size justification or further detail about the study’s statistical 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
| Stage | Dexcom G4 Platinum CGM & Activity Monitor |
|---|---|
| STARTED | 20 |
| COMPLETED | 18 |
| NOT COMPLETED | 2 |
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 | Dexcom G4 Platinum CGM and Activity Monitor |
|---|---|---|
| Participants analysed | 20 | |
| Age, Continuous | Years | 12 (7 to 17) |
| Sex: Female, Male: Female | Participants | 7 |
| Sex: Female, Male: Male | Participants | 13 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 19 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Body Mass Index | kg/m^2 | 18.7 (SD 0.6) |
| Total Daily Insulin Use | units of insulin/kg/day | 0.8 (0.55 to 1.12) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Supplemental Carbohydrate Interventions up to 3 Months From Baseline., measured over Up to 3 months.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | Supplemental Carb (SC) admin. per night |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change from baseline in supplemental carbohydrate interventions, measured in supplemental carbohydrate administrations per night, over up to 3 months. The registry record defines the participant-level measure as the number of supplemental carbohydrate administrations given by a parent divided by the number of days on which supplemental carbohydrate was given. It then describes calculating the median and interquartile range for subjects.
This outcome is intended to capture how often families used supplemental carbohydrate to prevent hypoglycemia, as defined by the registry’s measure. It is a practical measure of an intervention taken in response to glucose concerns, rather than a direct measure of glucose concentration or the duration of hypoglycemia. Its interpretation depends on the stated numerator and denominator: it is not defined as the number of administrations divided by every night in follow-up.
General statistical context: a median describes the middle of a set of values and is less affected by unusually high or low observations than a mean. The interquartile range describes the spread of the middle half of the observations. Reporting both can convey a typical value and variability when values are not evenly distributed.
The registry record does not report the baseline or follow-up medians, the interquartile ranges, or a numerical change. Therefore, the endpoint’s definition is available, but its observed result and precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a feasibility-oriented, single-group study in which activity monitor and glucose monitor information was to inform recommendations about nighttime basal insulin rates. The listed primary endpoint is a change in supplemental carbohydrate interventions from baseline. The record provides the outcome definition and a follow-up period of up to 3 months, but it does not report the numerical primary outcome. No direction, magnitude, or precision of change can therefore be described from the posted results.
No confidence interval, p-value, or other estimate of uncertainty for the primary outcome is reported in the registry record. Without an estimate and its uncertainty, readers cannot assess whether the observed change, if any, was small or large relative to the variability in the participants’ measurements. The registry record also does not report numerical findings for the secondary outcomes concerning daytime activity and nighttime nadir glucose or supplemental carbohydrate interventions among subjects with an activity effect.
The single-group structure matters for interpretation. A within-participant comparison uses each person’s baseline as a reference, but it does not show what would have happened over the same period without the recommendations. Changes may coincide with the intervention without being attributable to it. General statistical context: a concurrent comparison group can help distinguish intervention-associated change from time trends, changes in behavior, or other influences. This design, as described in the registry record, does not include such a group.
The enrollment listed is 20. That number describes the study enrollment in the registry; it does not by itself establish how many participants contributed complete endpoint data. The number with usable paired baseline and follow-up measurements, and any reasons for incomplete measurements, are not reported in the registry record. Those details would help readers judge how representative the reported participant-level summaries might be, if results were available.
The registry record marks the study completed, but completion status is not a numerical outcome. It does not establish that the primary endpoint changed in a particular direction or that the monitoring and recommendation approach prevented hypoglycemia. Nor does the absence of a posted numerical result show that no change occurred. It means the result cannot be evaluated from the registry record.
9. Statistical Methods Explained
What does a within-participant comparison estimate?
The primary outcome compares each participant’s measure during follow-up with that participant’s baseline measure. This approach focuses on change within individuals instead of comparing one group of participants with a different group. General statistical context: within-person comparisons can account for stable differences between participants, because each person serves as their own reference. They do not, on their own, rule out explanations such as changes over time, changes in care, or changes in how outcomes are recorded.
The study description identifies an initial two-week period for establishing activity baselines and a monitoring period of up to 3 months. The primary outcome description refers to a baseline period and a study period, but further details about the exact endpoint windows and the handling of participants with different amounts of follow-up are not reported in the registry record.
Why report a median and an interquartile range?
The primary outcome description specifies a median and interquartile range (IQR). General statistical context: the median is the central value when observations are ordered. The IQR spans the middle half of the observations, conveying spread without relying on the most extreme values. These summaries can be useful when measurements are skewed or when a small number of participants have unusually frequent events. The registry record does not report the underlying participant-level values, so the distribution and the degree of skew cannot be assessed.
The endpoint description first defines a measure for each subject and then says that the median and IQR of all subjects will be calculated. It does not provide a numerical summary of the baseline period, follow-up period, or change. It also does not explain how the group-level change was calculated from the participant-level measurements. Those analysis details are not reported in the registry record.
What role do the secondary outcomes play?
The registry lists correlation of daytime activity with nighttime nadir glucose as a secondary outcome. General statistical context: correlation describes how two measured quantities vary together. It does not establish that one quantity causes the other to change. The registry also names change from baseline in supplemental carbohydrate interventions among subjects with an activity effect. The definition of activity effect and the numerical results for either secondary outcome are not reported in the registry record.
Why can event counts vary more than a simple model expects?
General statistical context: counts of repeated events can show over-dispersion when their variability exceeds the assumptions of a simple count model. For example, participants may differ in their underlying event frequency, or events may cluster in time. A model that fails to account for such extra variability can produce uncertainty estimates that are too narrow. This is a general consideration for repeated event data, not a claim about the distribution in this study. The registry record does not report a model for the primary outcome or indicate whether over-dispersion was assessed.
How should planning calculations be read?
The registry’s sample-size assumptions describe planning illustrations using 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 the observed effect. Those are calculation assumptions, not evidence that the study had two randomized arms: the study design is listed as single group and allocation is NA. The calculations are planning illustrations, not observed power. The sample-size justification for the trial itself is not reported in the registry record.
General statistical context: a confidence interval is a range of values compatible with the data and the method used to estimate uncertainty. A narrow interval generally indicates greater precision than a wide interval, though interpretation also depends on the measure and design. No confidence interval for the primary outcome is reported in the registry record. No inferential model, adjustment strategy, or statistical test is reported either, so no model-based interpretation can be assigned to the endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry record names a primary outcome and secondary outcomes, but does not report a multiplicity strategy. Multiplicity arises when several outcomes or comparisons are assessed: the chance of at least one apparently unusual result can increase as the number of tests grows. General statistical context: researchers may address this by identifying a primary question in advance, adjusting inferential thresholds, or treating secondary findings as exploratory. Which approach was used in this study is not reported in the registry record.
The record does not report how missing endpoint observations were handled, how many participants had complete baseline and follow-up data, or whether any imputation was used. It also does not report analysis populations, such as a definition of which enrolled participants were included in each analysis. These omissions matter because the available measurements and the rules for including participants can affect a summary of change.
The registry lists enrollment as 20, but this does not establish that all 20 participants contributed data to every outcome. The record does not describe withdrawals, missed monitoring, incomplete uploads, or reasons for missing observations. It does not report interim analyses or stopping rules; their status is not reported in the registry record. The completed status alone does not supply those details.
General statistical context: missing data are not automatically harmless. If missingness is related to participant characteristics or outcomes, summaries among participants with observed measurements may differ from summaries that would have been obtained with complete follow-up. Without information about the amount, reasons, and handling of missing data, the extent of this concern cannot be assessed for this study.
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 |
|---|---|---|---|
| Dexcom G4 Platinum CGM & Activity Monitor | 0 | 20 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Dexcom G4 Platinum CGM & Activity Monitor | 0 of 20 |
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 |
|---|---|
| Dexcom G4 Platinum CGM & Activity Monitor | 1 of 20 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Dexcom G4 Platinum CGM & Activity Monitor |
|---|---|---|
| Medication Error (mother incorrectly programmed insulin pump) | Endocrine disorders | 1 of 20 |
For the Dexcom G4 Platinum CGM and activity monitor group, the registry lists 20 participants at risk for serious adverse events and 0 affected. It lists 20 at risk for other adverse events and 1 affected. Deaths are listed as 0. No serious adverse event terms are listed.
These are counts recorded in the registry, not estimates of comparative risk. The study has a single group and no like-for-like control comparison, so the adverse event figures do not quantify a difference between study treatment and control. The registry record does not describe the one other adverse event, its severity, timing, or relationship to monitoring or recommendations. Those details are not reported in the registry record.
General statistical context: an event count describes what was recorded in the study group, while a safety comparison requires context such as follow-up time, event definitions, and an appropriate comparator. A count of zero serious events does not establish that an event is impossible or that risk is absent; it describes the registry entry for this group. The record does not provide further detail on adverse event ascertainment or follow-up duration for safety reporting.
12. What the Result Does, and Does Not, Mean
The registry record describes a study that combined activity monitoring with continuous glucose monitoring and insulin pump data to inform recommendations about nighttime basal insulin. It also defines an outcome intended to track supplemental carbohydrate interventions over time. These elements make the study relevant to questions about how activity information might be incorporated into monitoring and insulin-management workflows.
The posted results do not report the primary endpoint’s numerical change, its variability, or an estimate of uncertainty. They also do not report numerical results for the secondary outcomes. Consequently, the record does not establish whether supplemental carbohydrate interventions became more frequent, less frequent, or remained similar during follow-up. It does not establish the size or precision of any change.
Even if a before-and-after change were reported, the single-group design would limit causal interpretation. Without a separate control group, a change over time could reflect factors other than the recommendations. General statistical context: association over time is not by itself evidence that an intervention caused the change. The study description and endpoint definition should therefore be distinguished from evidence of an intervention effect.
The record also does not establish whether any change in supplemental carbohydrate use corresponded to a change in overnight hypoglycemia, because no numerical outcome results are reported. The listed secondary outcome concerning nighttime nadir glucose is a separate question, and its results are not reported in the registry record. No conclusion about effectiveness or clinical benefit should be drawn from the study description alone.
The enrollment and safety counts describe the registry entries, but they do not fill the gap in the primary outcome results. The record can be read as documenting the study’s design, intended measures, and some safety counts; it cannot support a quantitative assessment of the primary question.
13. Why This Trial Matters Statistically
Statistically, this trial is a useful example of the difference between defining an outcome and reporting an outcome result. The registry record specifies a participant-level measure, a baseline comparison, and summaries using the median and interquartile range. Those details help clarify what the investigators intended to measure. Without numerical baseline and follow-up values, however, readers cannot estimate the amount of change or how much participants varied.
The study also illustrates why design structure must guide interpretation. A single-group before-and-after comparison can describe change among participants, but there is no concurrent control group in the registry record. A numerical change, if available, would therefore need to be interpreted with caution about other influences over time. The design does not answer the same question as a randomized comparison.
The outcome itself has a specific denominator: supplemental carbohydrate administrations are divided by the number of days on which supplemental carbohydrate was given. Keeping that definition in view is important when interpreting the measure. It should not be casually treated as a count per every night of observation, because that is not how the registry defines it.
Finally, the record makes visible the importance of complete reporting. Results for the primary and secondary outcomes, analysis populations, and missing-data handling are not reported in the registry record. Those details are necessary to judge the precision and robustness of outcome summaries. The listed enrollment and adverse event counts cannot substitute for outcome estimates or their uncertainty.
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 main limitation for interpretation is that the registry record does not report numerical results for the primary outcome. Without baseline and follow-up summaries or a numerical change, the direction and size of change cannot be evaluated. No uncertainty estimate is reported, so precision cannot be assessed either.
The design is single group, with no randomized or concurrent control comparison described. A within-participant baseline comparison can show change over time, but it cannot isolate the effect of the recommendations from other influences. The record does not report how recommendations were implemented, how consistently participants followed them, or whether insulin delivery changed as recommended.
The primary measure is based on supplemental carbohydrate administrations divided by days when supplemental carbohydrate was given. The registry record does not explain how days without such an intervention entered the analysis, or provide further detail about measurement and data collection. Interpretation is therefore limited to the stated definition.
Enrollment is listed as 20, but the number contributing complete primary outcome data is not reported. Follow-up completeness, missing-data reasons and handling, analysis populations, and the definition of activity effect are also not reported in the registry record. These omissions prevent assessment of how missing observations or participant selection may affect the outcomes.
Although the record lists two secondary outcomes and safety counts, it does not report numerical secondary results or details about the one other adverse event. The sample-size justification and statistical analysis plan are not reported in the registry record. These limits do not show that a particular result was absent; they constrain what can be concluded from the posted record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Adjusting Insulin Delivery to Activity — NCT02299479.
- Registry record last updated 2020-01-09; status last verified 2020-01.
- Results first posted 2018-12-28.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02299479, titled Adjusting Insulin Delivery to Activity (AIDA), is listed as completed and sponsored by Boston Children's Hospital. The registry record lists enrollment of 20, masking as none, allocation as NA, and a single-group model. The recorded start is 2015-07, and primary completion is 2017-06-27.
The study description concerns children and adolescents with type 1 diabetes using insulin pump therapy. Participants were to wear a Dexcom G4 Platinum continuous glucose monitor and an activity monitor, with data used to inform recommendations about nighttime basal insulin adjustments. The primary outcome is change from baseline in supplemental carbohydrate interventions over up to 3 months, summarized using medians and interquartile ranges.
The registry record reports 0 serious adverse events among 20 at risk, 1 other adverse event among 20 at risk, and 0 deaths. It does not report numerical results for the primary or secondary outcomes, the primary outcome’s uncertainty, or further details about the other adverse event. The record therefore describes the study and its measures but does not permit quantitative interpretation of its efficacy outcomes.