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 Insulin Sensitivity, Impaired Counterregulation, and Glucose Variability (NCT01439672), a na na study. The primary outcome is Insulin Sensitivity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01439672 |
| Phase | NA |
| Condition | Type 1 Diabetes Mellitus |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 35 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Virginia |
| Results posted | Yes |
2. Clinical Question
Population
Subjects with Type 1 Diabetes Mellitus are described in the registry record. The listed enrollment is 35. Detailed eligibility criteria and the characteristics of the enrolled group are not reported in the registry record.
Intervention
The single arm is described as receiving a mixed meal beverage along with insulin administration. The protocol summary also describes investigation of physiological parameters using a mixed meal test and induced hypoglycemia; details of the induced hypoglycemia procedure are not reported in the registry record.
Comparator
There is no separate comparator group. This is recorded as a single-group study, with allocation listed as NA and masking as none. It therefore does not provide a randomized comparison between different interventions or against a control arm.
Primary question
The primary question is how insulin sensitivity is measured following a mixed meal across admissions. The endpoint description specifies insulin sensitivity based on a minimal model of glucose kinetics, using plasma glucose and insulin measurements collected in response to the challenge.
Statistically, the study is framed as a physiological measurement question rather than an estimate of a treatment contrast. With no comparison group, the registry record does not establish a between-group difference or an effect relative to a control condition. It also does not report the numerical value of the primary endpoint, its variability, or an inferential analysis. The clinical question can therefore be described from the planned measurement, but the size and precision of the recorded outcome cannot be assessed from the registry record.
3. Trial Design
The registry identifies this study as a completed, single-group investigation sponsored by the University of Virginia. Its title is “Insulin Sensitivity, Impaired Counterregulation, and Glucose Variability.” The recorded phase and allocation are NA, and masking is listed as none. The registry lists enrollment as 35; this is the enrollment figure, not a reported count of participants with an available primary-endpoint measurement.
The arm description states that each subject will consume a mixed meal beverage with insulin administration to calculate insulin sensitivity. The protocol summary describes investigation of insulin sensitivity and counterregulatory function using a mixed meal test and induced hypoglycemia. The primary outcome description focuses on insulin sensitivity following a mixed meal across admissions, with a timeframe of 24 hours. The specific procedures, timing between admissions, and handling of repeated measurements are not reported in the registry record.
The record lists the study start as 2010-08 and primary completion as 2012-03. The study status is completed. These dates describe the registry timeline; they do not indicate when individual measurements occurred or how long each subject participated.
Because there is one study arm, the design does not support a randomized comparison between an intervention and a control. There is also no separately listed comparator or masking procedure. The registry record does not report the recruitment approach, eligibility criteria in detail, protocol deviations, participant flow, or the number of participants included in an endpoint analysis. Those omissions limit assessment of how representative the enrolled group was and how closely the completed study followed its intended procedures.
The listed outcome is continuous and described as a mean with standard deviation. No numerical outcome estimate or analysis is listed in the registry record. The design and endpoint can be described, but the observed level and precision of insulin sensitivity cannot be reconstructed from the available registry information.
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 | Insulin Sensitivity |
|---|---|
| STARTED | 35 |
| COMPLETED | 11 |
| NOT COMPLETED | 24 |
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 | Insulin Sensitivity |
|---|---|---|
| Participants analysed | 11 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 |
| Age, Categorical: >=65 years | Participants | 0 |
| Gender: Female | Participants | 4 |
| Gender: Male | Participants | 7 |
6. Primary Endpoint
The registry lists the primary outcome as Insulin Sensitivity, measured over 24 hours.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | 1/min per uU/mL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is titled Insulin Sensitivity and has the unit 1/min per uU/mL. It is described as a mean with standard deviation. The registry states that insulin sensitivity was measured using the minimal model of glucose kinetics, based on plasma glucose and insulin obtained frequently in response to a mixed meal challenge. Sampling is described as approximately every 5-15 minutes, and the outcome timeframe is 24 hours.
As a general statistical concept, a continuous endpoint retains information across its numerical range, rather than reducing measurement to categories such as event or no event. A mean gives a summary of the measured values, while a standard deviation describes their spread around that mean. The unit is essential to interpretation because it specifies the scale on which the measurement is expressed. The registry record does not explain the clinical interpretation of different values or provide a reference range.
The measure is used to quantify insulin sensitivity in the physiological setting described by the study. Frequent glucose and insulin measurements provide inputs to the stated kinetic model; they are not themselves the registry’s primary endpoint. The record does not provide the endpoint’s numerical mean or standard deviation, the number of measurements contributing to the estimate, or an analysis of variation across admissions. The measurement method and intended construct are described, but the result and its precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a continuous primary outcome and describes how it was intended to be measured, but it does not report a numerical result. There is therefore no recorded mean or standard deviation from which to describe the observed insulin-sensitivity level or the spread of measurements. The record lists zero analyses, so it does not provide an inferential estimate, confidence interval, or hypothesis-test result for the primary outcome.
This absence matters for interpretation. A study design and a defined endpoint explain what investigators intended to measure; they do not by themselves establish what was observed. Without a reported endpoint estimate, the magnitude of insulin sensitivity in the study group cannot be assessed from this record. Without a measure of precision, such as a confidence interval, it is also not possible to judge how precisely a population quantity may have been estimated.
As a general statistical concept, a confidence interval describes a range of values compatible with the data and the assumptions of the analysis. Its width reflects uncertainty, including the amount of information and variability. No confidence interval is reported in the registry record. The standard deviation named in the outcome specification would describe observed spread if reported, but it is not interchangeable with a confidence interval: one describes variation among measurements, while the other addresses uncertainty in an estimate.
The single-group structure further limits the kinds of conclusions that can be drawn. There is no randomized comparator against which to estimate a treatment contrast. The stated intervention is part of the measurement setting, but the record does not report a separate control condition or a contrast between conditions. Accordingly, the record cannot support an estimate of comparative treatment effect.
The registry describes measurements across admissions, but does not report how repeated measurements were summarized or modeled, whether every subject contributed measurements at each admission, or how missing observations were handled. Those details can affect the interpretation of a mean and its uncertainty. The analysis population is also not reported in the registry record.
These limitations are about the information available in the registry record, not proof that no analyses or detailed results exist elsewhere. For this record, the supported conclusions are limited to the intended single-group physiological measurement, the specified endpoint, and the stated measurement approach. Numerical findings and their statistical precision are not reported in the registry record.
9. Statistical Methods Explained
The registry describes insulin sensitivity as a continuous measure, summarized by a mean and standard deviation. It also describes the measurement approach as a minimal model of glucose kinetics using plasma glucose and insulin collected in response to a mixed meal challenge. The sampling interval is stated as approximately every 5-15 minutes, with a 24-hour timeframe. The record does not describe the model’s equations, parameter-estimation procedure, diagnostic checks, or rules for handling incomplete measurement sequences.
What does a mean describe?
As a general statistical concept, the mean is a measure of location: it summarizes a set of numerical observations with one central value. Its interpretation depends on what was measured, the units, and the group of observations included. In this study, the registry names the primary measure and its unit but does not report the mean. Consequently, the numerical level of insulin sensitivity in the analyzed observations cannot be described.
A mean can be influenced by unusually high or low observations. This is a general property of the statistic, not a claim about this study’s data. Assessing whether that issue matters would require access to the observed values or suitable summaries, neither of which is reported for the primary endpoint in the registry record.
What does the standard deviation describe?
In general, a standard deviation summarizes the spread of observations around their mean, in the same units as the measure. A small spread indicates observations are closer to their mean than a larger spread would indicate, under the same measurement scale. It does not directly quantify the uncertainty in the mean. The registry specifies standard deviation as the dispersion measure but does not report its value.
A confidence interval serves a different purpose. In general, it expresses uncertainty about an estimated quantity under an analysis and its assumptions. Its interpretation depends on the statistical method and the data used. No confidence interval or other uncertainty interval for the primary outcome is reported in the registry record, and no analysis is listed from which one could be interpreted.
Why collect glucose and insulin frequently?
The stated method uses plasma glucose and insulin measurements collected frequently after the mixed meal challenge as inputs to a model of glucose kinetics. In general, a sequence of measurements can characterize how a physiological quantity changes over time, while a model uses the pattern of measurements to estimate parameters. The registry’s description identifies the measurements and model but does not provide enough detail to assess model assumptions, fit, sensitivity to measurement error, or reproducibility of parameter estimates.
Repeated observations from the same subject are generally related rather than independent. As a general statistical matter, treating such observations as independent when they are correlated can lead to incorrect uncertainty estimates. Analyses may account for this dependence through an appropriate repeated-measures or subject-level approach. The registry record does not state how measurements within a subject or across admissions were handled, so no specific method should be attributed to this study.
What can a single-group design estimate?
In general, a single-group study can describe measurements in the group under the conditions used. Without a separate comparator, it cannot estimate a randomized between-group contrast. A pre-post or within-subject comparison could address a different question if measurements at distinct conditions or times were specified and analyzed, but the registry record does not report such an analysis. It would be inappropriate to infer one from the description of admissions or the challenge procedure alone.
The registry lists no analyses for this outcome. It does not report a test statistic, p-value, confidence interval, adjusted estimate, or model specification beyond naming the minimal model of glucose kinetics as the basis for measurement. Thus, statistical significance and the precision of an estimate cannot be evaluated from this record.
What does over-dispersion mean in general?
Over-dispersion is a general issue for outcomes whose variability is greater than a statistical model assumes. It is particularly relevant to some count-data models, where underestimated variability can make uncertainty appear too small. The primary outcome in this record is a continuous measure, and no count-model analysis is listed; the registry does not report an over-dispersion assessment. The general concept should not be mistaken for a finding about this study.
Sample-size calculations, when used for planning, depend on assumptions about the target effect, variability, significance level, and design. A planning illustration is not an observed study result and is not observed power. The record does not report the trial’s own sample-size justification or design assumptions. Any planning quantities associated with a hypothetical comparison should not be interpreted as a result from this single-group study.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one primary outcome measure and zero analyses. It does not report a statistical analysis plan, a hierarchy of hypotheses, adjustments for multiple testing, or a prespecified approach to secondary outcomes. The protocol summary mentions physiological parameters including insulin sensitivity and counterregulatory function, while the listed outcome measure is insulin sensitivity. The status of any other planned measurements and their analyses is not reported in the registry record.
As a general statistical concept, multiplicity arises when multiple outcomes, time points, subgroups, or statistical tests are considered. Testing many hypotheses can increase the chance of at least one apparently notable result. Researchers may address this through prespecified outcome hierarchies, adjusted thresholds, or other methods. No such method is reported for this study, and the absence of a listed analysis means the registry does not support an assessment of how multiplicity was handled.
Missing-data methods are also not reported in the registry record. The record does not state whether all enrolled subjects contributed to the primary endpoint, how incomplete glucose or insulin measurements were managed, or whether any observations were excluded. It does not describe imputation, complete-case analysis, or sensitivity analyses. These omissions matter because the analyzed observations and the assumptions used to address missingness can affect both an estimate and its uncertainty.
The analysis population is not reported in the registry record. No separate intention-to-treat, per-protocol, or other population is specified. The listed enrollment should therefore not be assumed to be the analysis denominator for the primary outcome. The record also does not report participant flow or reasons for missing measurements. These gaps prevent assessment of whether the outcome analysis included the enrolled group as intended.
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 |
|---|---|---|---|
| Insulin Sensitivity | 0 | 35 | 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 |
|---|---|
| Insulin Sensitivity | 2 of 35 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Insulin Sensitivity |
|---|---|---|
| Erythematous | Skin and subcutaneous tissue disorders | 1 of 35 |
| Ecchymosis | Vascular disorders | 1 of 35 |
The registry lists serious adverse events for the Insulin Sensitivity group as 0 among 35 at risk. It separately lists 2 other adverse events among 35 at risk. The record provides no serious adverse-event terms, and it does not identify the terms for the other adverse events. The number of deaths is not reported in the registry record.
These figures should be read as registry counts, not as evidence that an event was or was not caused by the study procedure. The registry record does not provide event narratives, severity details for the other events, timing, or an assessment of relatedness. It also does not describe how adverse events were collected or defined. Without those details, the counts cannot be used to make a causal attribution.
As a general statistical concept, a zero count in a group does not prove that the underlying event risk is zero. The precision of a safety estimate depends on the amount and completeness of follow-up and the event definitions, among other factors. The registry record does not provide enough information to quantify that uncertainty. It also does not report whether participants had different durations of observation or whether all adverse events were captured over the same period.
The at-risk counts are listed within the safety record and should not be treated as confirmation that the same number contributed to the primary endpoint analysis. The primary-outcome analysis population is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that the study was designed as a single-group physiological investigation of insulin sensitivity in subjects with Type 1 Diabetes Mellitus. It describes a mixed meal and insulin challenge, a continuous primary outcome, a minimal model of glucose kinetics, and frequent plasma glucose and insulin measurements. These details identify the intended measurement question and its broad methodological setting.
The registry record does not report a numerical primary-endpoint result, a standard deviation, or an inferential analysis. It therefore does not establish the measured level of insulin sensitivity or the precision of an estimate. No conclusion about the magnitude of a finding can be drawn from the endpoint description alone.
The design also does not provide a randomized comparator. As a general statistical principle, a single-group measurement study can describe the group under the study conditions, but it cannot by itself separate the effects of a challenge from other influences or estimate a comparative effect against an untreated or alternative-treatment group. The registry record does not report a within-subject contrast or a separate control condition.
The study title refers to impaired counterregulation and glucose variability, and the brief summary mentions counterregulatory function. However, the registry lists one outcome measure, insulin sensitivity. Other outcome estimates and their analysis are not reported in the registry record. The title should not be read as evidence that findings for every named topic were measured or reported.
In general, a planned measurement, a completed study status, and a numerical result are distinct pieces of information. Completion does not supply the missing outcome estimate. Likewise, safety counts do not answer the primary physiological question. The available record supports a description of the design and measurement method, but not a judgment about the observed endpoint value, the certainty of a result, or comparative effects.
13. Why This Trial Matters Statistically
Statistically, this study is useful to distinguish a measurement study from a comparative clinical trial. The registry identifies a single-group design and a continuous physiological endpoint. That framing matters: the primary inferential target would be a description of insulin sensitivity in the studied group under the challenge conditions, rather than a randomized contrast between treatment arms.
The measurement method also illustrates the role of repeated physiological data. The outcome description refers to frequent plasma glucose and insulin sampling after a mixed meal and a kinetic model. As a general concept, model-based measures can depend on both the data collected and the assumptions used to translate those data into an estimate. Reporting the model, data completeness, fit, and uncertainty is important for evaluating reproducibility and interpretation. The registry record does not report those analysis details or the numerical endpoint result.
A further statistical lesson is that protocol descriptions and results serve different purposes. The record states what the investigators intended to measure, but it does not supply the result or its precision. A completed status does not substitute for an outcome estimate, and an enrollment figure does not establish how many observations contributed to an analysis.
Finally, the record highlights why clear reporting of analysis populations, missing-data handling, and multiplicity plans matters. These details are necessary to understand which data support an estimate and how uncertainty should be interpreted. They are not reported in the registry record. The study can therefore be understood in broad design terms, while its primary statistical finding remains unavailable in this record.
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 statistical interpretation is that the registry record does not report the primary outcome result. Although the endpoint is defined as a mean with standard deviation, neither value is listed. No analysis is reported, so the record does not provide a confidence interval, p-value, or other measure of inferential uncertainty.
The single-group design has no listed comparator. It can describe the planned physiological measurement but does not estimate a randomized contrast between conditions. The record does not report a within-subject comparison, so one cannot assume that the measurements support a before-and-after analysis.
Important design and analysis details are absent. Eligibility criteria, participant characteristics, recruitment procedures, participant flow, the analysis population, and handling of protocol deviations are not reported in the registry record. The record also does not say how missing or incomplete glucose and insulin measurements were handled, how repeated measurements or admissions were accounted for, or what diagnostic checks were used for the model.
The measurement description names a minimal model of glucose kinetics but does not provide model specifications, validation details, or a measure of uncertainty in the model-derived endpoint. The registry does not report how the outcome was summarized across admissions or whether the planned timeframe was achieved for each subject. These details limit assessment of measurement reliability and the scope of any group-level summary.
The registry lists safety counts but does not provide event terms for the other adverse events, death counts, definitions, follow-up details, or relatedness assessments. It also does not report a statistical plan for multiplicity or a sample-size justification for the study’s own design. These omissions limit both efficacy-related statistical interpretation and safety assessment. They should be understood as reporting limitations of the registry record, not as evidence that the underlying study lacked procedures or analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Insulin Sensitivity, Impaired Counterregulation, and Glucose Variability — NCT01439672.
- Registry record last updated 2016-12-06; status last verified 2016-10.
- Results first posted 2015-04-14.
- 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
The registry identifies a completed, single-group study titled “Insulin Sensitivity, Impaired Counterregulation, and Glucose Variability,” sponsored by the University of Virginia. It lists enrollment as 35, phase and allocation as NA, and masking as none. The recorded study start is 2010-08 and primary completion is 2012-03.
The arm description concerns a mixed meal beverage with insulin administration. The primary outcome is continuous insulin sensitivity, described as a mean with standard deviation and measured using a minimal model of glucose kinetics from plasma glucose and insulin after a mixed meal challenge. The stated timeframe is 24 hours.
The registry record lists one outcome measure and zero analyses. It does not report the numerical primary result, its variability, or its precision. Safety entries list 0 serious adverse events and 2 other adverse events; the death count is not reported in the registry record. The design and measurement approach are described, but the statistical findings are not.