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 Continuous Glucose Sensor Profiles in Non-Diabetic Subjects (NCT00717977), a non-randomized phase 4 study. The primary outcome is Overall Mean Sensor Glucose by Age Group.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00717977 |
| Phase | Phase 4 |
| Condition | Healthy Subjects Without Type 1 Diabetes |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 74 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Jaeb Center for Health Research |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled 74 healthy subjects without type 1 diabetes. The record describes them as non-diabetic subjects. The age-group definitions and participant characteristics beyond this description are not reported in the registry record.
Intervention
The listed intervention is a continuous glucose monitor, classified as a device. The study objective was to establish reference sensor glucose ranges for devices used in a larger JDRF study. The record does not report device-specific results or explain how participants were assigned to particular devices.
Comparator
This was a non-randomized, single-group study, so the record does not describe a randomized comparator arm. It is not a like-for-like comparison of treatment groups. The registry record does not report a separate control group or a comparison with plasma glucose measurements for this study.
Primary question
The primary endpoint was overall mean sensor glucose by age group, measured in mg/dL over 48-72 hours. The stated objective was to establish reference sensor glucose ranges in healthy, non-diabetic subjects. The registry record does not report the age groups, their endpoint values, or the comparisons used to address the question.
The record’s background describes the relevance of reference sensor values to a larger randomized study of real-time continuous glucose monitoring in people with diabetes. That background is not itself a result of this study. The question addressed by this record concerns sensor glucose profiles in healthy subjects, rather than the efficacy, safety, or cost-effectiveness of glucose monitoring as an adjunct to usual testing. Numerical results needed to assess the primary question are not reported in the registry record.
3. Trial Design
The registry classifies this study as Phase 4, non-randomized, unmasked, and single-group. These design labels describe the registry classification; they do not establish that the study was designed to compare treatments. The record lists 74 participants and an intervention of continuous glucose monitor, classified as a device. Its status is completed. The recorded start is 2008-07 and primary completion is 2008-12.
The stated study objective was to establish reference sensor glucose ranges in healthy, non-diabetic subjects for devices used in a larger JDRF study and future investigations. The record’s background explains that continuous glucose monitors measure interstitial rather than plasma glucose and that sensor and simultaneous plasma readings can differ. This rationale helps explain why reference profiles in healthy subjects were of interest, but it does not establish that this study tested agreement between sensor and plasma measurements.
Although the primary endpoint is described as mean sensor glucose by age group, the record does not identify the age groups, explain how those groups were formed, or report whether every participant contributed data to every group. It also does not report how many devices were used within this study, how device use was allocated, or whether participants used more than one device. The larger study’s use of three devices is described in the background, but does not provide those details for this record.
Because the study is single-group and non-randomized, its design does not support a randomized between-group treatment contrast. The registry record does not report a concurrent comparator, masking procedures beyond the unmasked classification, or a protocol rationale for the design. Details on recruitment, eligibility criteria beyond the healthy non-diabetic description, follow-up, and the analysis population 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 | All Non-Diabetic Subjects |
|---|---|
| STARTED | 74 |
| COMPLETED | 74 |
| NOT COMPLETED | 0 |
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 | All Non-Diabetic Subjects |
|---|---|---|
| Participants analysed | 74 | |
| Age, Customized: 8-<15 years | Participants | 20 |
| Age, Customized: 15-<25 years | Participants | 17 |
| Age, Customized: 25-<45 years | Participants | 20 |
| Age, Customized: >=45 years | Participants | 17 |
| Sex: Female, Male: Female | Participants | 51 |
| Sex: Female, Male: Male | Participants | 23 |
| Race/Ethnicity, Customized: Non-Hispanic, Caucasian | Participant | 55 |
| Race/Ethnicity, Customized: Hispanic | Participant | 13 |
| Race/Ethnicity, Customized: African American | Participant | 1 |
| Race/Ethnicity, Customized: Other Race/Ethnicities | Participant | 5 |
| 2-hour post-oral glucose tolerance test (OGTT) | mg/dL | 96 (SD 22) |
| Fasting Glucose | mg/dL | 86 (SD 8) |
| Hemoglobin A1c: All | Percent | 5.3 (SD 0.3) |
| Hemoglobin A1c: 8-<15 years | Percent | 5.3 (SD 0.2) |
| Hemoglobin A1c: 15-<25 years | Percent | 5.2 (SD 0.2) |
| Hemoglobin A1c: 25-<45 years | Percent | 5.2 (SD 0.3) |
| Hemoglobin A1c: >=45 years | Percent | 5.5 (SD 0.3) |
6. Primary Endpoint
The registry lists the primary outcome as Overall Mean Sensor Glucose by Age Group, measured over 48-72 hours.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mg/dL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is titled overall mean sensor glucose by age group, with units of mg/dL and a timeframe of 48-72 hours. The description says a mean glucose value was calculated for every hour of the 24 hours of the day and that the measure is the average over all 24 hours. The endpoint is therefore intended to characterize an average sensor glucose profile across the day, rather than a single sensor reading. The record identifies standard deviation as the measure of dispersion.
As a general statistical concept, a mean summarizes the central level of a set of measurements. A standard deviation describes how spread out measurements are around that mean; it is not the same as uncertainty in the estimated mean. Reporting both can help characterize typical levels and variability, although neither alone shows the full shape of the data distribution.
Reference profiles in healthy, non-diabetic subjects were the stated purpose, in the context of continuous sensors measuring interstitial glucose. Such profiles may serve as a point of reference for interpreting sensor values in other investigations. However, the registry record does not report the mean values, standard deviations, participant counts within age groups, or age-group definitions. It therefore does not allow readers to quantify the endpoint or assess differences among age groups.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clear descriptive aim: characterize continuous sensor glucose profiles in healthy, non-diabetic subjects and establish reference ranges for sensors used in a larger study. It also identifies the primary measure as overall mean sensor glucose by age group. However, numerical primary outcome results are not reported in the registry record. Without those values, the magnitude and precision of the observed glucose profiles cannot be assessed.
The reported study design matters to interpretation. It is non-randomized and single-group, with no comparator arm described. The endpoint can therefore be understood as a profile measure within the study population, not as evidence of a treatment effect or a contrast between randomized groups. The record does not report whether age-group comparisons were performed, how age groups were defined, or the results of any such comparisons.
The record’s background notes that sensor glucose measures interstitial glucose and may differ from simultaneous plasma glucose values. That rationale motivates collecting reference sensor measurements, but it is not a finding from the study. No results comparing sensor and plasma readings are reported in the registry record. Nor are device-specific estimates reported, so the record does not establish whether profiles differed across devices.
The enrollment of 74 gives the total number of participants recorded, but does not show how many contributed to each endpoint or age group. The registry record does not report missing sensor measurements, the number of observations per participant, or how incomplete recordings were handled. Those details affect how representative the reported estimates would be, but the estimates themselves are not available in the registry record.
The measure’s stated dispersion is standard deviation. As a general statistical point, standard deviation describes variability in observed measurements, whereas a confidence interval would describe uncertainty about an estimated quantity under a statistical model. Confidence intervals and p-values for the primary endpoint are not reported in the registry record. No claim about statistical significance, precision, or the size of age-related differences can be made from the information recorded.
The background refers to glucose values inside and outside a target range and to glucose variability as outcomes in the larger JDRF study. Those are contextual motivations, not reported results for this study’s primary endpoint. The record lists 25 outcome measures and 3 analyses, but does not provide enough detail to identify all measures, analytic methods, or how they relate to the primary question. Accordingly, the registry information supports describing the aim and design, but not drawing quantitative conclusions about the glucose profiles.
9. Statistical Methods Explained
The primary measure is a continuous outcome: an amount measured on a numerical scale, expressed in mg/dL. The registry describes it as an overall mean sensor glucose value by age group, with standard deviation as its dispersion measure. The description states that hourly mean glucose values were calculated across the 24 hours of the day and averaged to form the measure. The observation timeframe is 48-72 hours. Numerical results and the detailed calculation procedure are not reported in the registry record.
What does a mean describe?
As a general statistical concept, a mean is a measure of central tendency. It summarizes a set of measurements with one value, which can make profiles easier to compare or describe. A mean can be influenced by unusually high or low observations, so its interpretation depends on the distribution of values and the way repeated measurements are aggregated. The registry record does not report the distribution of readings or enough detail to evaluate how the hourly values were combined for each participant and then across participants.
Standard deviation is a measure of spread around the mean. As a general explanation, a larger standard deviation indicates greater dispersion among observed values, while a smaller one indicates that values are more closely clustered around the mean. It is not a measure of how precisely a group mean has been estimated. A confidence interval is commonly used to express uncertainty about an estimate; the registry record does not report confidence intervals for the primary endpoint.
What can age-group reporting establish?
Reporting a mean by age group can describe how the endpoint varies across defined groups. Interpretation requires knowing how the age groups were formed, how many participants were included in each, and whether the estimates are accompanied by measures of uncertainty. These details, along with age-group values and any formal comparisons, are not reported in the registry record. The title of the endpoint alone does not establish that age groups differed.
Why does the design affect analysis?
The registry classifies the study as non-randomized and single-group. As a general statistical principle, random allocation can help make groups comparable for a treatment contrast, while a single-group design does not provide a randomized contrast. Here, the recorded objective is reference characterization in healthy subjects. It should not be interpreted as a controlled estimate of an intervention effect. The record does not describe a comparator group, and no adjusted or unadjusted group contrast is reported.
Repeated sensor readings within a participant are not independent observations in the ordinary sense: measurements from the same person can be related. As a general methods point, analyses of repeated measurements should account for their dependence when making inferential claims. The registry description does not report the statistical model, the handling of repeated readings, or whether the primary analysis used participant-level summaries. It is therefore not possible to determine from the record how within-person correlation was addressed.
What do significance tests and intervals add?
As a general explanation, a p-value evaluates how compatible data are with a specified null model, under the assumptions of the test. It does not measure the probability that a hypothesis is true, nor does it quantify the practical importance of an observed value. A confidence interval gives a range of values compatible with the data and model at a stated confidence level. Neither p-values nor confidence intervals for the primary endpoint are reported in the registry record. No statistical significance or precision claim can be assessed from the endpoint description alone.
How should planning illustrations be read?
The registry information describes planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These assumptions describe an illustration, not the original study’s design or a reported sample-size justification. In particular, assumptions involving equal allocation between two arms do not describe this non-randomized, single-group study. The record does not report a sample-size justification for the trial. Any planning quantities should not be interpreted as observed power or as evidence that the study was adequately powered for its primary objective.
More generally, power is a planning concept concerning the chance of detecting a specified effect under stated assumptions. It is not a property that can be recovered from the observed result alone. A retrospective illustration based on an observed effect also inherits uncertainty in that estimate. The registry record does not report a protocol-based power calculation or the assumptions that would be needed to judge one.
What information is needed to reproduce the analysis?
Reproduction would require a fuller description of the analysis population, participant-level measurement handling, age-group definitions, device use, missing-data rules, and the statistical model. The registry record does not report these details. It lists 25 outcome measures and 3 analyses, but does not identify all of their definitions or explain any adjustment for multiple testing. Those omissions limit assessment of analytic choices and the reliability of comparisons, even apart from the absence of numerical endpoint results.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 25 outcome measures and 3 analyses. The primary measure is identified as overall mean sensor glucose by age group, but the record does not describe all secondary outcomes, specify which analyses correspond to which measures, or state whether all analyses were planned in advance. It also does not report a multiplicity strategy, such as adjustment of significance thresholds or a prespecified hierarchy of outcomes.
As a general statistical concept, examining multiple outcomes or comparisons can increase the chance of finding an apparently notable result by chance. Whether adjustment is needed depends on the questions and analysis plan; the registry record does not provide enough detail to evaluate that issue. Numerical results, p-values, and confidence intervals for the primary endpoint are not reported in the registry record, so multiplicity’s impact on inference cannot be assessed.
Missing-data methods and analysis populations are also not described in the registry record. The total enrollment is 74, but the number with usable sensor data for the primary endpoint, the number contributing to each age group, and the treatment of incomplete sensor recordings are not reported. The record does not state whether all enrolled subjects were included in the analysis or whether any exclusions occurred. Without these details, readers cannot determine whether the analyzed participants represent the enrolled group or how missing observations may have affected estimates.
The record also does not report a statistical analysis plan, interim analyses, or a sample-size justification. Their absence from the registry information should not be taken to establish what was or was not done outside the 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 |
|---|---|---|---|
| All Non-Diabetic Subjects | 0 | 74 | 0.0% |
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 |
|---|---|
| All Non-Diabetic Subjects | 0 of 74 |
The adverse-event record lists 74 subjects at risk for serious adverse events and 0 affected. It also lists 74 at risk for other adverse events and 0 affected. These are reported counts for the group identified as all non-diabetic subjects. The deaths field is not reported in the registry record, and no top serious adverse-event terms are listed.
A count of 0 affected means that no affected subjects are recorded in these registry fields. It does not establish that an event is impossible, nor does it describe the completeness of event ascertainment, the duration of safety observation, or the criteria used to classify events. Those details are not reported in the registry record. In particular, a missing death count should not be read as a recorded count of zero.
These figures are limited to the safety entries recorded for this study. They do not provide event rates by device, participant characteristics, or follow-up period, and they should not be interpreted as a comparison with another group. The single-group, non-randomized design has no randomized safety comparator described in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed, single-group study enrolled 74 healthy non-diabetic subjects to characterize continuous glucose sensor profiles. Its primary endpoint was overall mean sensor glucose by age group, measured in mg/dL over 48-72 hours, with a description based on averaging hourly values across the 24 hours of the day. The stated purpose was to establish reference sensor glucose ranges for devices used in a larger study and future investigations.
These registry entries describe the study’s question and framework, not the numerical answer. Mean values by age group, standard deviations, confidence intervals, and p-values are not reported in the registry record. Consequently, the size and precision of the endpoint estimates, and whether the age-group profiles differed, cannot be determined from the registry information. Device-specific results and comparisons with plasma glucose are also not reported.
The study is not a randomized comparison of monitoring strategies or treatments. Its design does not support conclusions about the effect of continuous glucose monitoring in people with diabetes, and the background discussion of a larger JDRF study is not a result of this record. The record’s stated reference-range objective should also not be confused with proof that the resulting ranges are representative of all healthy people; recruitment details and participant characteristics beyond the broad population description are not reported.
As a general statistical point, an estimate’s usefulness depends on both the observed value and its uncertainty, as well as on how participants and measurements were selected and analyzed. Those elements cannot be fully evaluated without the numerical results and analysis details. The registry record supports a description of the intended reference-profile study and its recorded design, but not a conclusion about the level or variability of sensor glucose in the enrolled group.
13. Why This Trial Matters Statistically
Reference data and treatment comparisons answer different statistical questions. This study was intended to characterize sensor glucose profiles in healthy, non-diabetic subjects, while the registry background describes a separate, larger randomized study of real-time continuous glucose monitoring. Keeping those aims distinct prevents a descriptive reference study from being mistaken for evidence about the effects of monitoring in another population.
The design also illustrates why the endpoint and analysis population matter. A mean sensor glucose value by age group can describe the central level of measurements, while standard deviation can describe their variability. To judge how precisely those values are estimated, readers also need sample counts and uncertainty measures. The registry record does not report the endpoint values, age-group sizes, confidence intervals, or analysis details needed for that assessment.
The background notes that sensor glucose reflects interstitial rather than plasma glucose and can differ from a simultaneous plasma measurement. This is relevant context for why sensor-specific reference profiles were sought. It does not mean this study reported a direct validation comparison. Distinguishing the scientific motivation from the actual recorded endpoint is important when interpreting a registry entry.
Finally, the record’s non-randomized, single-group design and lack of reported numerical results place clear limits on inference. The study can be described as aiming to establish reference profiles, but the registry information does not permit a quantitative judgment about the profiles, age-group differences, or device differences. That separation between study purpose, design, and reported evidence is central to sound statistical interpretation.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record does not report numerical results for the primary endpoint. This prevents assessment of the mean sensor glucose values, their standard deviations, the precision of estimates, or the size of any age-group differences. Although the endpoint is defined by age group, the groups themselves and their participant counts are not reported.
Further details needed to interpret the measurements are also absent. The record does not describe participant-level sensor data completeness, the number of readings contributing to each estimate, missing-data handling, or the statistical method used to account for repeated measurements. Device-specific use and results are not reported. The background refers to three devices used in the larger JDRF study, but does not establish device assignment or device-specific analyses for this study.
The single-group, non-randomized design does not provide a randomized comparator. It therefore does not support a controlled treatment-effect interpretation. The record does not report direct comparisons with plasma glucose, even though sensor-plasma differences are part of the stated rationale. It also does not report recruitment methods or participant characteristics beyond the healthy non-diabetic description, limiting assessment of how broadly the sample might represent other populations.
Finally, the registry information does not report a sample-size justification, a statistical analysis plan, or a multiplicity approach. It lists 25 outcome measures and 3 analyses without describing them in detail. The planning assumptions noted in the record are illustrations based on an observed effect, not evidence of the original design rationale. These limitations concern what is reported in the registry record and do not establish what information may exist elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Continuous Glucose Sensor Profiles in Non-Diabetic Subjects — NCT00717977.
- Registry record last updated 2016-10-19; status last verified 2016-09.
- Results first posted 2010-10-18.
- 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
This completed Phase 4 study was classified as non-randomized, unmasked, and single-group. It enrolled 74 healthy subjects without type 1 diabetes. The recorded start is 2008-07, and primary completion is 2008-12. The listed intervention is a continuous glucose monitor.
The stated objective was to establish reference sensor glucose ranges in healthy, non-diabetic subjects. The primary endpoint was overall mean sensor glucose by age group, in mg/dL, over 48-72 hours. The description says hourly mean values were averaged across the 24 hours of the day; standard deviation was identified as the dispersion measure.
Numerical primary endpoint results, age-group definitions, confidence intervals, and analysis details are not reported in the registry record. The adverse-event entries record 0 affected subjects for serious and other adverse events among 74 at risk in each category. The death count is not reported.