Characteristics of Glargine in Type 2 Diabetics: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Characteristics of Glargine in Type 2 Diabetics (NCT00574912), a na phase 1 study. The primary outcome is Maximum Glucose Infusion Rate.

2. Clinical Question

The study asks whether different doses of insulin glargine are associated with different glucose-metabolism responses over a 24-hour experimental period in people with type 2 diabetes. Its stated hypothesis concerns endogenous glucose production, glucose disposal, and carbohydrate and lipid flux. The primary registered endpoint is maximum glucose infusion rate, measured in umol/kg/min over 24 hours.

This is a pharmacodynamic dose-response question, rather than a comparison of long-term clinical outcomes. The registered aim is to examine short-period physiological responses under the study conditions. A measured difference in glucose infusion rate would address that specific endpoint, but would not by itself establish effects on outcomes that are not measured in this record.

3. Trial Design

The registry describes a Phase 1, single-group study sponsored by Vanderbilt University Medical Center. The condition is type 2 diabetes. The study is marked completed, with a start date of 2007-03 and primary completion date of 2009-09. Allocation is listed as NA, and masking is listed as none. The registry therefore does not describe a randomized, masked comparison of parallel groups.

The intervention list includes placebo and four subcutaneous insulin glargine doses: 0.5, 1.0, 1.5, and 2.0 u/kg body wt. The arm description says that participants received a single placebo dose with blood glucose monitoring over 24 hours, followed by insulin glargine 8 weeks later in increasing doses. It says each dose was separated by 8 week. This description indicates a sequence of conditions, but the record does not provide a detailed schedule beyond those statements.

The registry lists enrollment as 20. In contrast, the primary endpoint population description says 12 participants in each arm. Because this is a single-group record with a sequence of conditions, the term arm does not establish that the conditions were assigned to separate, independent groups. The record does not reconcile the enrollment and endpoint population descriptions or explain whether every participant contributed data at every condition.

The record does not report eligibility criteria, participant characteristics, details of adherence, or how the sequence was implemented beyond the description above. The design information supports interpreting the study as a small, short-period pharmacodynamic investigation, but not as a randomized parallel-group efficacy trial. The registry record does not report the rationale for the chosen doses or spacing.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: 12 participants in each arm

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.

Population: One participant may have received more than one intervention.

6. Primary Endpoint

The registry lists the primary outcome as Maximum Glucose Infusion Rate, measured over 24 hours.

The primary endpoint is maximum glucose infusion rate, expressed in umol/kg/min, during a 24-hour experimental period. The description says it measures changes in glucose infusion rate during that period. The registered endpoint is continuous, and the stated summary measure is a mean with standard error as its dispersion measure.

In general, glucose infusion rate is a way to quantify the rate at which glucose is being infused under the experimental conditions. A maximum value focuses on the highest rate reached during the observation period, rather than the average rate across the entire period. A continuous endpoint can retain information about the magnitude of measured responses, rather than reducing observations to categories such as response or no response.

The study’s stated hypothesis also refers to endogenous glucose production, glucose disposal, and carbohydrate and lipid flux. Those concepts describe aspects of glucose and energy metabolism, but the registry identifies maximum glucose infusion rate as the primary endpoint. The record does not report numerical endpoint results, the method used to identify the maximum, or additional endpoint definitions that would clarify how the other stated metabolic measures were analyzed.

The intended use of this endpoint is to characterize short-term physiological response across the listed conditions. It should not be interpreted as a direct measure of long-term glycemic control or a clinical outcome. The registry record does not report enough endpoint data to assess the magnitude or precision of any observed dose-related pattern.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies maximum glucose infusion rate as a continuous primary outcome summarized by a mean and standard error. It lists one outcome measure and one analysis. These entries describe the broad form and count of registered outcome and analysis records; they do not supply the statistical procedure or numerical result.

What does the mean describe?

In general, a mean is an average of observed measurements within a defined analysis group or condition. For this study, the endpoint description says the mean concerns maximum glucose infusion rate over the 24-hour experimental period. The registry record does not report the observed means, the underlying measurements, or a detailed description of which observations contributed to each mean.

What does the standard error describe?

In general, a standard error describes the precision of an estimated quantity, such as a mean. It is not the same as the spread of individual observations. A standard error can help show how much uncertainty surrounds a group average, while a separate measure of variability would describe how dispersed participant-level values are. The endpoint record names standard error, but the standard errors themselves are not reported in the registry record.

How would a dose-response analysis be read?

In general, a dose-response analysis examines whether an outcome changes in relation to increasing exposure levels. Here, the registered conditions include placebo and increasing glargine doses. A transparent report might describe the observed outcome at each condition and explain whether the analysis estimates a trend or makes pairwise comparisons. The registry record does not report those estimates or specify which approach was used. The listed doses alone do not establish that the endpoint changed monotonically or that any particular dose differed from placebo.

The single-group model and the described sequence also affect what a comparison can mean. When the same participants experience multiple conditions, measurements may be related within a participant. In general, an analysis that accounts for this relationship can differ from one that treats observations as independent. The arm description suggests a placebo condition followed by dose conditions, but the record does not explicitly state the analysis unit, the statistical model, or how within-participant correlation was handled. It also does not report whether dose order was randomized or counterbalanced. No assumptions about these methods can be made from the registration fields alone.

Why does over-dispersion matter?

In general, over-dispersion means that observed variability is greater than a statistical model expects. It is especially relevant for some count outcomes, where an overly restrictive model can understate uncertainty. The primary outcome in this record is continuous, and no count-model method is reported. There is no basis to claim that over-dispersion was present or that any particular correction was used. More generally, the statistical model should match the outcome’s distribution and the structure of the observations; the registry record does not provide enough detail to assess that match.

What can be inferred from the planning assumptions?

The record describes sample-size illustrations based on a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence about the actual trial analysis. A planning illustration can show how an assumed effect and design relate to a possible sample size in a hypothetical study. It is not observed power, and it does not show that the original study was planned or analyzed in that way. The record does not report the trial’s own sample-size justification or provide the numerical planning illustrations in the registry record recorded.

Because the record does not report the observed effect, it is not possible to assess how the illustrations relate to the study’s actual findings. Recalculated values based on posted summary statistics are not available in this record. No recalculated estimate should be substituted for a sponsor analysis; if a discrepancy were identified, the sponsor’s own analysis would take precedence. No such outcome comparison can be evaluated because the numerical endpoint results are not reported.

What does a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under a specified statistical procedure. It communicates uncertainty about an effect estimate in a way that a point estimate alone cannot. A narrow interval indicates greater precision than a wide interval, though interpretation also depends on the estimate and the question being asked. The registry record does not report confidence intervals for the primary endpoint, so the precision of any dose contrast cannot be judged this way.

A p-value, when reported, addresses how compatible the observed data are with a specified null model and its assumptions. It does not measure the size or importance of an effect. The registry record does not report a p-value or specify a null hypothesis for the endpoint. Without the underlying estimates and analysis description, the significance or uncertainty of a dose-response comparison cannot be reconstructed from the study labels alone.

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.

R code and output

arm <- c("Placebo", "0.5 Units of Glargine/kg", "1.0 Units of Glargine/kg", "1.5 Units of Glargine/kg", "2.0 Units of Glargine/kg")
n   <- c(12, 12, 12, 12, 12)
m   <- c(0.3, 2.6, 5.5, 6.8, 9.5)
sp  <- c(0.3, 0.9, 1.5, 2, 2.1)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
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  Placebo  12  0.300  1.039  -0.360  0.960
CARM  0.5 Units of Glargine/kg  12  2.600  3.118  0.619  4.581
CARM  1.0 Units of Glargine/kg  12  5.500  5.196  2.199  8.801
CARM  1.5 Units of Glargine/kg  12  6.800  6.928  2.398  11.202
CARM  2.0 Units of Glargine/kg  12  9.500  7.275  4.878  14.122

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and one analysis. This does not, by itself, establish that the full analysis plan contained only one outcome, comparison, or analytic decision. Several treatment conditions are named, and the record does not explain whether the intended analysis involved a trend test, separate comparisons, or another approach. It also does not report a multiplicity adjustment or say whether one was considered.

Multiplicity arises in general when several statistical hypotheses are assessed, increasing the chance of at least one apparently noteworthy result under a set of null hypotheses. How to address it depends on which comparisons were planned and how they relate to the study question. The registry record does not provide enough detail to determine the family of comparisons or the method, if any, used to account for multiple testing.

Missing-data handling is not reported in the registry record. The record does not state whether measurements were missing, how incomplete 24-hour observations were handled, or whether any analysis required a complete set of measurements across conditions. It also does not report a rule for excluding measurements or participants from an endpoint analysis.

The analysis population is not fully described. The registry reports enrollment as 20 and describes the primary endpoint population as 12 participants in each arm, without explaining the relationship between these entries. The record does not identify an intention-to-treat population, a per-protocol population, or another defined analysis set. These details limit interpretation of how broadly the endpoint estimates would apply to enrolled participants, even if the numerical estimates were available.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry safety entries list placebo and four glargine-dose groups. For each listed group, 12 participants are recorded as at risk for serious adverse events and 12 as at risk for other adverse events. The recorded counts affected are zero for serious adverse events and zero for other adverse events in each group. These are the figures entered in the registry for the listed categories.

Zero recorded events in these entries should be read narrowly. The registry record does not report the methods or duration of adverse-event surveillance, whether the listed counts reflect complete follow-up, or how event terms were collected and classified. The record also does not report detailed event listings. Therefore, the entries describe what is recorded in these categories, rather than establishing that no adverse events of any kind occurred.

Death counts are not reported in the registry record; the death fields are null. A null entry is not the same as a recorded count of zero. The displayed safety information also does not establish comparative safety, particularly because the study is labeled single group and allocation is NA rather than randomized. The registry record does not provide a statistical comparison of safety outcomes among conditions.

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

This record establishes that a Phase 1 study was registered to examine short-term responses to placebo and several insulin glargine doses in people with type 2 diabetes. Its primary endpoint was maximum glucose infusion rate during a 24-hour experimental period. The listed study question and hypothesis focus on glucose metabolism and related metabolic fluxes.

The record does not report the numerical primary endpoint results. It therefore does not show the mean glucose infusion rate for any condition, the size or direction of differences across conditions, or the precision of a dose-response estimate. No conclusion about whether the endpoint rose, fell, or remained similar across the listed conditions can be drawn from the information recorded. Lack of a reported estimate is not evidence of no effect.

The endpoint is a short-period physiological measure, not a long-term clinical outcome. Even if numerical differences were available, they would describe the measured endpoint under the study conditions. They would not, by themselves, establish an effect on outcomes that the record does not report. The registry’s stated hypothesis about endogenous glucose production, glucose disposal, and carbohydrate and lipid flux also should not be treated as a set of demonstrated findings.

The design labels and sequence description constrain interpretation. Allocation is NA, masking is none, and the model is single group. The record describes placebo followed by increasing glargine doses, with intervals between conditions; it does not describe a randomized parallel-group control comparison. The registry also does not explain how the enrollment figure relates to the endpoint population description.

The safety entries report zero affected participants for the serious and other adverse-event categories in the listed groups, while death counts are not reported in the registry record. These entries should be interpreted according to their recorded categories and should not be generalized beyond the information available. In short, the record identifies an important physiological question and its planned endpoint, but the posted results do not provide the outcome estimates needed to answer that question.

14. Why This Trial Matters Statistically

This study is statistically interesting because its registered question concerns dose response across several exposure conditions, while the record identifies the design as single group and allocation as NA. Those features make it important to distinguish a sequence of conditions from a randomized comparison of separate groups. The design labels alone do not tell the reader how the analysis accounted for the relationship among measurements or for the order in which conditions occurred.

The endpoint is continuous and summarized by a mean with standard error. That combination emphasizes both an average response and its precision, but interpretation depends on seeing the numerical estimates and understanding the analysis population. The posted record identifies the endpoint without reporting its means or standard errors, illustrating why an outcome label alone cannot establish the direction, magnitude, or reliability of a finding.

The record also contains different descriptions of study size: enrollment is listed as 20, while the endpoint description says 12 participants in each arm. Since the registry does not reconcile those entries, a statistical reader should retain the distinction rather than infer a single analysis count. Clear reporting of denominators and analysis populations is central to judging how much information an estimate contains.

Finally, the sample-size assumptions describe hypothetical planning illustrations based on an observed effect, while the registry record does not report the trial’s own sample-size justification or endpoint results. This distinction matters because planning assumptions do not replace observed estimates, and a sample-size illustration is not observed power. The record is useful for understanding the intended physiological question and design context, but it does not support an assessment of the study’s primary statistical finding.

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 principal limitation for statistical interpretation is that the registry record does not report the primary endpoint estimates. There are no reported means, standard errors, confidence intervals, p-values, or dose-response contrasts in the recorded results. The effect’s direction, size, and precision therefore cannot be assessed.

The design description leaves important analytical details unspecified. Although the study is labeled single group and the arm description gives a sequence of placebo followed by increasing doses, the record does not state whether dose order was randomized, whether all participants completed all conditions, or how the analysis handled repeated observations and possible period effects. It does not report the statistical model or the planned contrasts.

There is also an unresolved difference between the listed enrollment of 20 and the primary endpoint description of 12 participants in each arm. The registry record does not clarify whether these figures refer to different populations, stages, or other aspects of the study. It does not define an analysis population or explain missing-data handling.

Additional limitations include the absence of reported eligibility criteria and participant characteristics, and the lack of detail about the measurement procedure used to identify the maximum glucose infusion rate. The record does not report how the other metabolic quantities in the hypothesis were operationalized or analyzed. It also does not provide a sample-size justification for the completed study. These gaps restrict assessment of the endpoint’s reproducibility and of how broadly results might apply, even apart from the missing outcome estimates.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Characteristics of Glargine in Type 2 Diabetics — NCT00574912.
• Registry record last updated 2017-04-17; status last verified 2017-03.
• Results first posted 2015-08-03.
• 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.

19. Record Summary

The registry record describes a completed Phase 1, single-group study of insulin glargine dose response in type 2 diabetes, sponsored by Vanderbilt University Medical Center. It lists placebo and subcutaneous glargine doses of 0.5, 1.0, 1.5, and 2.0 u/kg body wt. The stated primary endpoint is maximum glucose infusion rate in umol/kg/min over 24 hours, summarized as a mean with standard error.

Allocation is NA and masking is none. The arm description places placebo before increasing glargine doses. Enrollment is listed as 20, while the endpoint population is described as 12 participants in each arm; the registry record does not explain the difference.

The posted results do not report numerical primary endpoint estimates or their uncertainty. Safety entries record zero serious and zero other adverse events in each listed group, while death counts are not reported in the registry record. The primary dose-response question consequently remains unanswered by the reported endpoint data.