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 Glucose Variability in Type 1 Diabetes (T1D) and Glycaemic Responses to Food Composition. (NCT06546657), a registered phase not stated study. The primary outcome is Mean Postprandial Glucose.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT06546657 |
| Phase | Phase not stated |
| Condition | Type 1 Diabetes |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 96 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Stirling |
| Results posted | Yes |
2. Clinical Question
Population
Children and young people with type 1 diabetes who regularly used Dexcom continuous glucose monitoring were the intended population. The study proposed to recruit approximately 435 participants; the recorded enrollment was 96. The primary outcome description refers to CGM data from 71 participants and 387 breakfast meals.
Intervention
The record identifies Breakfast as the intervention. Participants were asked to provide access to CGM data and to complete morning and evening questionnaires for seven consecutive days. The morning questionnaire covered breakfast, included a meal photograph, and asked about insulin dosage. The evening questionnaire covered diabetes management, food and fluid intake, and activities during the four-hour postprandial period.
Comparator
No randomized comparator or like-for-like control group is described. The record says allocation was not stated and cautions that the arms are not a like-for-like control comparison. Therefore, the primary question is descriptive rather than a stated estimate of a treatment contrast.
Primary question
The primary outcome is mean postprandial glucose, measured using CGM readings from the start of a meal through four hours after it, at five-minute intervals. The record describes the measure across 387 breakfast meals consumed by 71 participants. It does not report a numerical mean or standard deviation, so the size and precision of the observed glucose level cannot be assessed from the registry record.
3. Trial Design
The study is listed as completed and was sponsored by the University of Stirling. Its recorded start date is 2021-02-06, and its primary completion date is 2021-11-20. The condition listed is type 1 diabetes. The official title describes an investigation of diurnal glucose variability in paediatric patients and responses to different food compositions.
The study description proposes collecting baseline demographic, clinical, treatment, and anthropometric information through local dietitians. Participants were asked to provide access to Dexcom CGM data throughout the recording period. For seven consecutive days, they were to complete two questionnaires: one at breakfast and another in the evening. The morning questionnaire covered the breakfast meal, a photograph of it, and insulin dosage. The evening questionnaire covered diabetes management, food and fluid intake, and activities during the four-hour postprandial period.
The proposed recruitment was approximately 435 children and young people, while recorded enrollment was 96. The primary outcome description covers 387 breakfast meals from 71 participants. The registry record does not explain the difference between proposed recruitment, enrollment, and the population represented in that outcome description.
No random allocation is stated. The record explicitly cautions that the arms are not a like-for-like control comparison. The available description is therefore a record of glucose and meal-related observations rather than a stated randomized comparison of assigned treatments. It says the data would be described using univariate, bivariate, and multivariate analysis, but does not give the detailed model specifications or identify which analysis produced the primary outcome.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: 96 participants were enrolled 7 participants did not respond or dropped out of the study before sharing CGM data. 89 participants shared their CGM data for glucose variability analysis and of these 74 submitted the breakfast and postprandial questionnaires of which 71 completed with corresponding CGM data.
Glucose Variability (CGM Data)
| Stage | Glucose Variability Then Breakfast and Postprandial Questionnaires |
|---|---|
| STARTED | 89 |
| Glucose Variability | 89 |
| COMPLETED | 89 |
| NOT COMPLETED | 0 |
Breakfast and Postprandial Questionnaire
| Stage | Glucose Variability Then Breakfast and Postprandial Questionnaires |
|---|---|
| STARTED | 74 |
| COMPLETED | 71 |
| NOT COMPLETED | 3 |
Analysis population for the primary outcome, as defined in the registry: CGM data over 4-hour postprandial period for 387 breakfast meals consumed by 71 participants
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 | Glucose Variability and Postprandial Glucose |
|---|---|---|
| Participants analysed | 89 | |
| Age, Continuous | years | 10.1 (SD 3.8) |
| Sex: Female, Male: Female | Participants | 40 |
| Sex: Female, Male: Male | Participants | 49 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United Kingdom | participants | 89 |
| HbA1c | mmol/mol | 57.7 (SD 9.3) |
| Disease duration | years | 4.0 (2.0 to 6.5) |
| Insulin regimen: MDI user | Participants | 22 |
| Insulin regimen: CSII user | Participants | 66 |
| Insulin regimen: Unknown | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Mean Postprandial Glucose, measured over From baseline (start of meal) to 4 hours postprandial at 5min intervals.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mmol/l |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is mean postprandial glucose, in mmol/l. It is described as the mean CGM reading from baseline, defined as the start of the meal, through four hours after the meal, with readings taken at five-minute intervals. The outcome description refers to 387 breakfast meals consumed by 71 participants.
A mean is a summary of the central level of a continuous measurement. In general, averaging glucose readings across a defined post-meal period can describe the overall glucose level during that interval. It is useful as a broad summary, but does not by itself describe the timing or size of a peak, the amount of fluctuation, or how long readings spend within a specified range. The registry lists other outcomes related to excursions, time to peak, area under the curve, coefficient of variation, time in range, and meal glycaemic index, which address different aspects of glucose patterns.
The registry record does not report the numerical primary mean or its standard deviation. It therefore does not permit an assessment of the observed level, variation across observations, or precision of the estimate. The endpoint definition is available, but its numerical result is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record defines a primary outcome and describes the observations contributing to it: mean postprandial CGM glucose across 387 breakfast meals from 71 participants. It does not report the outcome’s numerical mean or standard deviation. Consequently, the registry record does not establish the observed glucose level or how variable the measurements were. Without those statistics, the magnitude and precision of the primary outcome cannot be interpreted quantitatively.
The outcome is a descriptive measure over a specified interval after breakfast. It is not, on its own, a contrast between two assigned treatment groups. The record does not state an allocation method and cautions that the arms are not a like-for-like control comparison. A difference between groups, if reported elsewhere, would therefore need to be interpreted in light of how those groups were formed and whether their characteristics were comparable. No such comparative result is reported in the registry record.
The count of meals is not the same as the count of participants. Each participant may contribute more than one meal observation, and observations from the same person can be related. As a general statistical consideration, methods that account for within-person clustering may be relevant when repeated observations are analyzed. The registry record does not report how any dependence between meals from the same participant was handled. It also does not report the number of meals contributed by each participant or the extent of missing CGM or questionnaire data.
The study description lists several additional glucose and meal-related outcomes, including mean and peak excursions, time to peak, area under the curve, coefficient of variation, time in range, and glycaemic index measures. These can describe complementary features of post-meal glucose patterns, but their numerical results are not stated in the record. The registry lists 15 outcome measures and 8 analyses; it does not explain how those analyses map to the outcomes.
Recorded enrollment was 96, while the primary outcome description concerns 71 participants and 387 meals. The registry record does not explain this difference. The study proposed approximately 435 recruits, but that proposed figure does not establish why the recorded enrollment was lower or whether the intended recruitment target changed. In the absence of numerical outcome estimates, analysis details, and an explanation of the analysis population, the evidence that can be drawn from the registry is limited to the study’s stated objective, data collection plan, and outcome definition.
9. Statistical Methods Explained
The primary measure is a continuous outcome: mean postprandial glucose in mmol/l. The record specifies that it is summarized as a mean with standard deviation and defines the observation interval as the start of the meal to four hours postprandial, with CGM readings at five-minute intervals. The primary description covers 387 breakfast meals consumed by 71 participants. Although the type of summary is stated, its numerical value and standard deviation are not reported in the registry record.
What does a mean and standard deviation describe?
In general, a mean summarizes the central level of a set of measurements. A standard deviation describes how spread out measurements are around that mean. They answer different questions: the mean describes a typical level, while the standard deviation describes variation among the observations included in the summary. Neither statistic alone tells whether measurements changed in a particular direction over time or whether any difference is attributable to a particular food composition.
The interpretation of these summaries depends on what counts as an observation. Here, the outcome description identifies meals as the basis for the CGM summary, while also identifying the number of participants contributing those meals. Repeated meal records from one person are not necessarily statistically independent. As a general matter, treating clustered observations as independent can make uncertainty estimates too small. Analyses can account for clustering, for example by modeling participant-level dependence, but the registry record does not report whether or how that was done.
Why does the measurement interval matter?
The endpoint covers four hours after the start of a meal and uses CGM readings at five-minute intervals. Defining a common interval makes clear which part of the glucose profile contributes to the summary. In general, a period average can conceal the shape of the profile: two profiles can have similar means but differ in peak level, timing, or variability. The record lists secondary measures intended to characterize some of those features, including mean glucose excursion, peak glucose excursion, time to peak, area under the curve, coefficient of variation percentage, and time in range in minutes.
The registry also lists measures involving breakfast glycaemic index and glucose variability, as well as mean postprandial glucose and glycaemic index. These outcomes concern related but distinct quantities. Their exact operational definitions, calculation details, and analysis populations are not reported in the registry record. The record lists 15 outcome measures and 8 analyses, but does not describe which analyses correspond to which measures.
What does the stated analysis approach tell readers?
The study description says the data would be statistically described using univariate, bivariate, and multivariate analysis. In general, univariate analysis describes one variable at a time; bivariate analysis examines relationships between two variables; and multivariate analysis considers several variables together. These labels do not specify the statistical model, assumptions, covariates, handling of repeated observations, or method for estimating uncertainty. Those details are not reported in the registry record.
A confidence interval, when reported, gives a range of values compatible with the data under the model and assumptions used. Its width indicates the precision of the estimate: a wider interval indicates greater uncertainty than a narrower one. No confidence interval for the primary endpoint is reported in the registry record. A p-value, if reported, would address compatibility with a specified null model, not the size or practical importance of an observed pattern; the registry record does not report a primary p-value.
How should planning calculations be read?
The stated assumptions for the planning illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect defined as a fraction of the observed effect. The record describes these as planning illustrations computed from the observed effect, not as the study’s own design. It says that non-time-to-event illustrations are expressed as participants per arm for 80% power, while time-to-event illustrations use total events. These are hypothetical planning quantities, not observed power and not evidence that the study had a particular probability of detecting an effect. The registry record does not report the numerical planning results or a sample-size justification for the trial itself. Moreover, the record cautions that the arms are not a like-for-like control comparison, so equal-allocation assumptions in a planning illustration should not be taken as evidence of a randomized two-arm design.
10. Confidence Intervals for Each Arm
No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.
| Arm | Participants | Mean | Standard deviation | 95% CI for the mean |
|---|---|---|---|---|
| Glucose Variability Then Breakfast and Postprandia | 71 | 9.200 | 2.700 | 8.561 to 9.839 |
R code and output
arm <- c("Glucose Variability Then Breakfast and Postprandia")
n <- c(71)
m <- c(9.2)
sp <- c(2.7)
sd <- sp # posted standard deviations
for (i in seq_along(n)) {
se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}
CARM Glucose Variability Then Breakfast and Postprandia 71 9.200 2.700 8.561 9.83911. Multiplicity, Missing Data and Analysis Populations
The registry record lists 15 outcome measures and 8 analyses. Multiple outcomes and analyses create a general statistical issue: when many hypotheses are tested, the chance of at least one apparently unusual result can increase if each is judged separately using the same threshold. Methods such as prespecifying a primary outcome, controlling a family-wise error rate, or using false-discovery-rate procedures can address different multiplicity goals. The record identifies mean postprandial glucose as the primary outcome, but does not report whether any adjustment for multiple testing was planned or used. It also does not explain how the 8 analyses relate to the 15 outcomes.
The registry description gives a proposed recruitment of approximately 435 and recorded enrollment of 96. The primary outcome description covers 71 participants and 387 breakfast meals. The registry record does not report why those counts differ, which participants or meals were included or excluded, or whether the outcome population was defined before analysis.
Missing-data handling is not reported in the registry record. The record does not state how unavailable CGM readings, incomplete questionnaires, or missing baseline information were treated. It also does not describe whether any imputation was used, whether analyses were restricted to complete records, or what assumptions about missingness were made.
The analysis populations are not fully specified. The primary endpoint description identifies participants and meals contributing to its measure, but does not state eligibility rules for inclusion in that calculation or whether other populations were used for the remaining outcomes. The record therefore does not establish how missingness, exclusions, or multiplicity may affect the reported analyses.
12. 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 |
|---|---|---|---|
| Glucose Variability Then Breakfast and Postprandial Questionnaires | 0 | 89 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Glucose Variability Then Breakfast and Postprandial Questionnaires | 0 of 89 |
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 |
|---|---|
| Glucose Variability Then Breakfast and Postprandial Questionnaires | 0 of 89 |
The registry record lists one group, titled “Glucose Variability Then Breakfast and Postprandial Questionnaires.” For this group, 89 participants are recorded as at risk for serious adverse events and 0 as affected. The count for other adverse events is also 0 among 89 at risk, and deaths are recorded as 0. No top serious adverse-event terms are listed.
These figures describe the events recorded for the stated group and denominator. A reported count of 0 means that no events of that category were recorded in the registry entry; it does not establish that an event was impossible or that every participant had identical risk. The group’s at-risk count of 89 differs from recorded enrollment of 96. The registry record does not explain the difference, define the safety collection period in further detail, or state why the denominator differs.
These safety figures should not be read as evidence about a comparison between treatments. The record does not state randomized allocation and cautions that the arms are not a like-for-like control comparison. The figures are a registry summary of recorded adverse events, not a comparative estimate of event risk.
13. What the Result Does, and Does Not, Mean
The registry record establishes that a completed study collected CGM and meal-related information in children and young people with type 1 diabetes. Its primary outcome was defined as mean CGM glucose over four hours after breakfast, based on 387 meals from 71 participants. It also lists several secondary outcomes intended to describe glucose excursions, timing, variability, time in range, and relationships with breakfast composition.
The record does not report the numerical primary mean, its standard deviation, confidence interval, or p-value. It therefore cannot show the level or precision of the primary outcome from the information recorded. Nor does it report numerical results for the listed secondary measures. A clear endpoint definition is useful, but it is not a substitute for the estimate and its uncertainty.
The data collection description does not establish a causal effect of one food composition relative to another. No randomized allocation is stated, and the record cautions that the arms are not a like-for-like control comparison. Observed differences in a non-randomized setting can reflect differences in participants, meals, or circumstances as well as the food composition of interest. Which factors were measured or adjusted for in any analysis is not reported in the registry record.
Recorded enrollment was 96; the primary outcome description concerns 71 participants and 387 meals, while the study proposed recruiting approximately 435. These counts describe different aspects of the record, and the reasons for their differences are not reported. The registry does not specify the missing-data approach or the methods used to account for repeated meals within participants.
Accordingly, the record supports a description of the study’s purpose, data collection, and planned outcome framework. It does not, by itself, support a numerical conclusion about the primary glucose level, a comparative treatment effect, or the precision of any estimate. Those questions require numerical results and analysis details that are not reported in the registry record.
14. Why This Trial Matters Statistically
This study raises an important statistical feature of nutrition and glucose research: repeated real-world observations can capture variation across meals and times of day, but the observations are nested within people. The registry describes 387 breakfast meals from 71 participants. In general, such data can provide information about meal-to-meal patterns, while also requiring attention to the dependence among records from the same participant when estimating uncertainty.
The outcome framework also distinguishes average glucose from other properties of a post-meal profile. A mean across the four-hour interval summarizes overall level, while peak excursion, time to peak, variability, and time in range describe different features. Considering multiple summaries can give a broader statistical description than relying on a mean alone. At the same time, the registry lists 15 outcome measures and 8 analyses and does not report how multiplicity was handled, so separate findings would need careful interpretation.
The record also illustrates why counts at different stages matter. It reports a proposed recruitment of approximately 435, enrollment of 96, a primary outcome population of 71 participants, and 387 meals. Those figures are not interchangeable: some describe recruitment or enrollment, while others describe the observations represented in the endpoint. The reasons for the differences are not reported, making transparent population definitions and missing-data information important for assessing generalizability and potential selection effects.
Finally, clearly defined endpoints are only one part of interpreting a study. Numerical estimates, uncertainty measures, analysis methods, and a suitable comparison are needed to assess the strength and meaning of findings. The registry record defines the primary measure and describes the collection approach, but its missing numerical results and limited analysis details constrain what can be concluded statistically.
15. 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 a numerical result for the primary endpoint, its standard deviation, or an interval quantifying uncertainty. Without these, readers cannot assess the central glucose level or how precisely it was estimated. Numerical results for the listed secondary outcomes are also not reported in the registry record.
The record describes no randomized allocation and explicitly warns that the arms are not a like-for-like control comparison. It therefore does not establish a randomized estimate of differences between food compositions. The detailed approach to comparing meals, if any, is not reported.
The proposed recruitment was approximately 435, recorded enrollment was 96, and the primary outcome description covers 71 participants and 387 meals. The record does not explain the differences among these counts. It also does not report participant or meal inclusion criteria for the primary analysis, the number of observations contributed per participant, or how missing CGM readings and questionnaire responses were handled.
Repeated meals from a participant may be statistically related; as a general methodological concern, the handling of that dependence can affect uncertainty estimates. The registry record does not state whether models accounted for participant-level clustering. It names univariate, bivariate, and multivariate analysis but does not provide model specifications, covariate choices, or the allocation of analyses across outcomes.
The record lists 15 outcome measures and 8 analyses, but does not report a multiplicity strategy. It also does not give a trial-specific sample-size justification. The stated planning assumptions refer to illustrative calculations, while the numerical outputs are not reported in the registry record. Together, these omissions limit assessment of precision, bias, and the scope of any conclusions that might be drawn from the full study results.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Glucose Variability in Type 1 Diabetes (T1D) and Glycaemic Responses to Food Composition. — NCT06546657.
- Registry record last updated 2025-03-19; status last verified 2025-01.
- Results first posted 2025-03-19.
- 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.
19. Record Summary
NCT06546657 is listed as a completed study sponsored by the University of Stirling. The recorded start date is 2021-02-06, and the primary completion date is 2021-11-20. It concerns type 1 diabetes and investigates diurnal glucose variability and responses to food composition in paediatric patients.
The study description covers Dexcom CGM data and morning and evening questionnaires collected over seven consecutive days. The primary outcome is mean postprandial glucose in mmol/l, defined over four hours from the start of a meal at five-minute intervals. Its description refers to 387 breakfast meals from 71 participants. Recorded enrollment is 96, compared with proposed recruitment of approximately 435.
The record lists 15 outcome measures and 8 analyses. It reports no numerical primary outcome result, and does not report detailed analysis, missing-data, or multiplicity methods. No randomized allocation is stated, and the record cautions that the arms are not a like-for-like control comparison.