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 Effects of Agonists of Glucagon Like Peptide - 1 Receptors (GLP-1R) on Arterial Stiffness, Endothelial Glycocalyx and Coronary Flow Reserve in Patients With Coronary Artery Disease and Patients With Diabetes Mellitus (NCT03010683), a randomized na study. The primary outcome is Differences in Pulse Wave Velocity at Baseline and 3, 6 and 12 Months After Treatment With Metformin or Agonist GLP-1R..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03010683 |
| Phase | NA |
| Condition | Type 2 Diabetes Mellitus, Coronary Artery Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 60 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Athens |
| Results posted | Yes |
2. Clinical Question
Population
The registry record lists type 2 diabetes mellitus and coronary artery disease as conditions. Its study summary describes patients with type 2 diabetes without coronary artery disease, patients with type 2 diabetes and coronary artery disease, and obese patients with an abnormal oral glucose tolerance test. The record does not report the enrollment criteria or how participants were distributed among these described groups.
Intervention
The intervention listings name liraglutide and metformin. The study summary frames the question around changes in vascular measures after treatment with metformin or a glucagon-like peptide-1 receptor agonist. The record does not provide arm descriptions that clarify treatment schedules, doses, or how treatment was assigned within the population groups.
Comparator
Metformin is the comparator to liraglutide in the listed interventions. The record describes randomized allocation and a parallel model, but it does not report the allocation sequence, concealment procedures, or details of the comparison within each population group.
Primary question
The primary outcome concerns differences in carotid-femoral pulse wave velocity, measured by tonometry, at baseline and 3, 6 and 12 months after treatment with metformin or a GLP-1 receptor agonist. The clinical question is whether these treatment groups show different patterns in this measure of arterial stiffness over the stated assessment times. The registry record does not report the measurements or a treatment-effect estimate, so it does not establish the direction or size of any observed difference.
3. Trial Design
The registry record describes NCT03010683 as a randomized, single-masked, parallel study with an enrollment of 60. Its status is completed. The phase is listed as NA. The sponsor is the University of Athens. The recorded start is 2015-11, and primary completion is recorded as 2017-06. These registry entries describe the study structure and administrative record; they do not provide a full protocol or the results of the trial.
The intervention listings are liraglutide and metformin. The brief summary describes a study of patients with type 2 diabetes without coronary artery disease, patients with type 2 diabetes and coronary artery disease, and obese patients with abnormal oral glucose tolerance test results. The condition listings name type 2 diabetes mellitus and coronary artery disease. The record does not explain the relationship between these population descriptions, whether every described group entered the same comparison, or how randomization was organized across them. Arm descriptions are blank.
The primary outcome is carotid-femoral pulse wave velocity, measured using tonometry. The stated assessment schedule is baseline, 3 months, 6 months and 12 months after treatment. The record also lists secondary outcomes concerning endothelial glycocalyx and pulse wave velocity, and endothelial glycocalyx and coronary flow reserve. Although six outcome measures are recorded, detailed definitions for all of them are not present in the registry record.
Randomization can reduce systematic differences between assigned groups when implemented appropriately, while masking can limit some forms of bias. The registry record does not identify who was masked or report the procedures used to implement randomization. The completed status does not substitute for outcome data: the registry record does not report the primary outcome values or an analysis comparing treatment groups.
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 | Liraglutide | Metformin |
|---|---|---|
| STARTED | 30 | 30 |
| COMPLETED | 30 | 30 |
| NOT COMPLETED | 0 | 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 | Liraglutide | Metformin | Total |
|---|---|---|---|---|
| Participants analysed | 30 | 30 | 60 | |
| Age, Categorical: <=18 years | Participants | 3 | 3 | 6 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 | 20 | 40 |
| Age, Categorical: >=65 years | Participants | 7 | 7 | 14 |
| Sex: Female, Male: Female | Participants | 10 | 10 | 20 |
| Sex: Female, Male: Male | Participants | 20 | 20 | 40 |
| Race/Ethnicity, Customized: Greeks | participants | 30 | 30 | 60 |
| Pulse Wave Velocity | m/s | 11.8 (SD 2.5) | 11.2 (SD 3) | 11.5 (SD 2.8) |
6. Primary Endpoint
The registry lists the primary outcome as Differences in Pulse Wave Velocity at Baseline and 3, 6 and 12 Months After Treatment With Metformin or Agonist GLP-1R., measured over Baseline, 3 months, 6 months and 12 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | m/s |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the difference in carotid-femoral pulse wave velocity (PWV), measured by tonometry, at baseline and 3, 6 and 12 months after treatment with metformin or a GLP-1 receptor agonist. The unit is m/s, and the registry identifies the measure as a mean with standard deviation. The outcome is framed as a set of measurements across time rather than as one specified comparison at a single follow-up assessment.
PWV measures how quickly a pressure wave travels along the arteries. In general, a higher PWV is interpreted as greater arterial stiffness. The study summary notes that arterial stiffness is associated with increased cardiovascular disease risk, which helps explain why the investigators selected a vascular measure as a primary outcome. This association does not mean that a change in PWV by itself demonstrates a change in clinical events or establishes a treatment benefit.
The registry record does not specify a primary contrast, such as a particular follow-up time, an average change across follow-up, or a model-based treatment-by-time effect. It also does not provide the observed means, standard deviations, changes, confidence intervals, or a statistical test for this endpoint. Thus, the outcome definition and assessment schedule are available, but the magnitude and precision of the comparison are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record establishes that pulse wave velocity was the primary outcome and that measurements were scheduled at baseline, 3 months, 6 months and 12 months. It does not provide the resulting measurements or a treatment comparison. Therefore, no direction, magnitude, or precision of an effect on PWV can be described from the registry record. In particular, it is not possible to determine whether mean PWV increased, decreased, or remained similar within either treatment group, or whether the groups differed over follow-up.
The listed outcome is a repeated measurement. A complete interpretation would require clarity about the comparison being estimated: for example, whether the main focus was a difference between groups at a follow-up time, a difference in change from baseline, or an overall pattern across assessment times. The registry record does not report which contrast or statistical model was used. It also does not provide confidence intervals or a p-value. Without those results, neither statistical evidence for a group difference nor its precision can be assessed.
The trial is described as randomized and parallel, which identifies important design features. However, the record does not describe allocation methods or the treatment groups in enough detail to assess how randomization was carried out. Single masking is recorded, but the masked party or parties are not identified. The record also does not clarify how the described population groups were represented in the treatment comparison.
The study summary includes endothelial glycocalyx and coronary flow reserve among the vascular topics of interest, and the listed secondary outcomes refer to endothelial glycocalyx with PWV and with coronary flow reserve. These descriptions indicate other measured domains, but the registry record does not report their results. It is not possible to assess whether findings across outcomes agreed, differed, or were uncertain.
The adverse-event listings record zero serious adverse events, zero other adverse events, and zero deaths in each listed treatment group, with 30 at risk in each group. These figures describe what is entered in the registry record. They do not by themselves establish that no events occurred, show how actively events were sought, or quantify safety with high precision.
Overall, the record describes the design and intended outcome schedule, but it does not provide efficacy estimates or their uncertainty. The completed status should not be read as evidence that a particular result was obtained. No conclusion about the effect of liraglutide relative to metformin on PWV, endothelial glycocalyx, coronary flow reserve, or clinical outcomes can be drawn from the posted results in this record.
9. Statistical Methods Explained
The registry identifies the study as randomized, single-masked, and parallel. In general, randomization assigns participants to treatment groups by chance, which is intended to reduce systematic differences between groups at the start of a study. Its success in a particular trial cannot be judged from the design label alone; details such as sequence generation, concealment, and baseline characteristics are relevant. Those details are not reported in the registry record. A parallel design means groups receive their assigned treatment over the study period rather than switching through a sequence of treatments. The record does not provide further protocol details about treatment duration or adherence.
Single masking means that masking was applied to one party or category of people, but the registry record does not say who was masked. Masking can limit the influence of expectations on care, measurement, or reporting, depending on who is unaware of treatment assignment. Without knowing the masked party and how masking was maintained, the likely protection against bias cannot be assessed.
What does the endpoint description imply?
PWV is a continuous outcome, and the record identifies the reported summary as a mean with standard deviation. A mean describes the average measured value in a group. A standard deviation describes how dispersed individual measurements are around that average. These summaries are not substitutes for a comparison between randomized groups. To estimate a treatment contrast, an analysis also needs to define the relevant time point or change over time, account for the repeated measurements where appropriate, and report an estimate with its uncertainty. The registry record does not report those elements.
Repeated measurements from the same participant are related: measurements from one person tend to share characteristics. In general, an analysis of measurements over time should account for that within-person correlation. A model that treats all measurements as independent could misstate uncertainty. Methods for repeated measures can estimate differences across time while representing the correlation structure, but the registry record does not identify whether such a method was used. It also does not state whether the main comparison was based on follow-up values, changes from baseline, or another summary.
How should uncertainty be understood?
A confidence interval is a range of estimates compatible with the data and the assumptions of the analysis. It communicates the precision of an estimated contrast: a narrower interval indicates more precision than a wider interval. A p-value addresses how compatible the data are with a specified null hypothesis under the statistical model; it is not a measure of effect size or clinical importance. Neither confidence intervals nor p-values for the primary outcome are reported in the registry record, so statistical uncertainty cannot be evaluated.
The standard deviation listed as the endpoint's dispersion is distinct from the standard error and from a confidence interval for a treatment effect. The standard deviation describes variation among measurements, while a standard error quantifies uncertainty in an estimate. A treatment comparison requires information about the group estimates and the method used to calculate its uncertainty. Those result details are not reported.
What do the planning assumptions mean?
The record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such figures, when reported, are prospective planning illustrations under stated assumptions; they are not observed power and do not establish how likely the trial was to detect a real effect. The record does not report the effect estimate needed to assess such planning values alongside the primary results. The primary outcome also has several assessment times and is not reduced in the registry record to one comparison. Any planning illustration should therefore be read in light of its stated assumptions and the particular effect it is intended to detect, not as evidence about the trial's observed findings.
Over-dispersion is a general concern when outcomes vary more than a statistical model assumes. It can make uncertainty estimates too small if the model fails to account for the extra variation. It is not possible to determine whether over-dispersion is relevant to the PWV analysis from the registry record, and the record does not identify a model or diagnostic procedure.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is scheduled at baseline, 3 months, 6 months and 12 months. Considering several assessment times can create multiple opportunities to test for differences. When multiple hypotheses are tested, the chance of at least one apparently notable result can increase unless the analysis plan addresses multiplicity. A prespecified primary time point, a repeated-measures model with a defined overall test, or an adjustment strategy are possible general approaches. The registry record does not report which approach, if any, was used, nor does it specify a primary contrast among the assessment times.
The record lists secondary outcome topics involving endothelial glycocalyx, PWV, and coronary flow reserve. Testing multiple outcomes can raise related multiplicity concerns. The registry record does not report a hierarchy of outcomes, a multiplicity adjustment, or the number of analyses conducted. Although six outcome measures are recorded, detailed analysis plans for those measures are not reported.
Missing-data handling is not reported in the registry record. It does not state whether all randomized participants contributed measurements at each assessment, how withdrawals or missed visits were handled, or whether imputation or another method was used. Repeated-measures analyses can rely on assumptions about the pattern and causes of missing observations; those assumptions cannot be assessed without the analysis description and follow-up information.
The analysis population is also not reported in the registry record. There is no description of whether analyses included all randomized participants, participants who followed the assigned treatment, or another defined group. This matters because exclusions after randomization can affect the comparability created by random assignment. No statement about the analysis population or its relation to the randomized groups can be made from the available registry entry.
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 |
|---|---|---|---|
| Liraglutide | 0 | 30 | 0.0% |
| Metformin | 0 | 30 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Liraglutide | 0 of 30 |
| Metformin | 0 of 30 |
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 |
|---|---|
| Liraglutide | 0 of 30 |
| Metformin | 0 of 30 |
The registry lists zero serious adverse events among 30 at risk in the liraglutide group and zero among 30 at risk in the metformin group. It also lists zero other adverse events and zero deaths in each group. These are the entries recorded for the listed groups; they should not be interpreted as proof that the treatments have no adverse effects.
A zero count in a limited study can be compatible with uncertainty about the frequency of uncommon events. The registry record does not describe how adverse events were defined, collected, monitored, or attributed, or whether follow-up was complete for all participants at risk. It also does not provide event-level details or a safety analysis. The figures therefore describe the registry's reported counts, but they do not support a precise comparison of safety between treatments.
The serious and other adverse-event categories are distinct entries in the record, and deaths are reported separately. These counts should not be combined or treated as a comprehensive assessment of all potential harms. Interpretation requires the study's safety definitions, observation period, and reporting procedures, which are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record documents a randomized, single-masked, parallel comparison involving liraglutide and metformin, with PWV measured at baseline, 3 months, 6 months and 12 months. It also identifies endothelial glycocalyx and coronary flow reserve as topics in secondary outcome descriptions. These details show which vascular measures the study set out to examine, but they do not tell readers what values were observed or how treatment groups compared.
Because the registry record does not report primary outcome results, it cannot establish whether PWV differed between groups or changed over time. It also cannot show the size of any difference, how precise an estimate was, or whether the observed pattern was compatible with no group difference. The same limitation applies to the listed secondary outcome topics. No conclusion about the effect of treatment on clinical cardiovascular events is available from these outcome descriptions.
PWV is a measure related to arterial stiffness, and the study summary describes arterial stiffness as associated with cardiovascular disease risk. A measure associated with risk is not itself a clinical event. Even a reported change in PWV would need careful interpretation: it would not, on its own, prove a change in cardiovascular outcomes or identify the cause of such a change.
The registry's completed status indicates the study is recorded as completed, not that its results are present in this entry. The adverse-event counts are also limited to the entries recorded for the listed groups and do not establish absence of risk. The appropriate conclusion is therefore about the information available: the study design and outcome schedule are described, while the comparative efficacy results and their uncertainty are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically notable for its repeated vascular measurements and its comparison of two drug interventions in a population description that includes diabetes, coronary artery disease, and abnormal oral glucose tolerance. Repeated measurements can provide information about how an outcome changes over time, but they require a clearly defined comparison and an analysis that accounts for measurements from the same participant. The registry record gives the assessment schedule but not the model or contrast used.
The distinction between a measured vascular characteristic and a clinical outcome is also important. PWV is used to characterize arterial stiffness, which the study summary relates to cardiovascular risk. Statistical evidence about PWV would answer a question about that measure; it would not automatically answer a question about cardiovascular events. Keeping the endpoint and the broader clinical interpretation separate prevents overstatement.
Registry interpretation also depends on reporting completeness. A randomized design is informative, but an assessment of its findings requires group-level results, an effect estimate, and measures of uncertainty. The record does not include the primary results or analysis details, so the design cannot be converted into a conclusion about treatment differences. The study's recorded completion status does not resolve that gap.
Finally, a series of time points and several vascular outcome topics raise questions about prespecification, multiplicity, missing observations, and analysis populations. Those are general statistical considerations rather than evidence of a flaw in this study. The registry record does not report enough analysis detail to determine how they were handled. Its value for readers is therefore chiefly in documenting the study question and design, while leaving the statistical interpretation of results unresolved.
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 entry does not report the primary outcome results, group means, standard deviations, treatment contrasts, confidence intervals, or p-values. Without these, the magnitude and precision of any difference in PWV cannot be assessed. Results for the listed secondary outcome topics are also not reported.
The population description is not fully reconciled across the record. The condition listings identify type 2 diabetes mellitus and coronary artery disease, while the brief summary describes patients with type 2 diabetes without coronary artery disease, patients with both conditions, and obese patients with an abnormal oral glucose tolerance test. The record does not explain how those groups relate to enrollment or treatment assignment. The arm descriptions are blank.
The protocol and analysis details are limited. The registry records randomization, single masking, and a parallel model, but does not describe the randomization procedure, identify who was masked, define the primary treatment contrast, or state the statistical model. Missing-data procedures, analysis populations, and multiplicity handling are not reported in the registry record. The detailed definitions of all six outcome measures are not available in the entry.
The adverse-event counts are recorded, but safety definitions, collection procedures, follow-up completeness, and event attribution are not described. The listed counts therefore cannot support a detailed comparison of harms. These limitations reflect what is and is not documented in the registry record; they should not be taken as evidence that unreported procedures or results do not exist elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Agonists of Glucagon Like Peptide - 1 Receptors (GLP-1R) on Arterial Stiffness, Endothelial Glycocalyx and Coronary Flow Reserve in Patients With Coronary Artery Disease and Patients With Diabetes Mellitus — NCT03010683.
- Registry record last updated 2021-03-05; status last verified 2021-03.
- Results first posted 2021-03-05.
- 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
NCT03010683 is recorded as a completed, randomized, single-masked, parallel study sponsored by the University of Athens, with enrollment of 60. The registry lists liraglutide and metformin as interventions. The study summary describes populations involving type 2 diabetes, coronary artery disease, and abnormal oral glucose tolerance.
The primary outcome is carotid-femoral PWV measured by tonometry at baseline, 3 months, 6 months and 12 months. Secondary outcome descriptions concern endothelial glycocalyx with PWV and with coronary flow reserve. The registry record does not report the primary or secondary outcome results, the statistical analysis, or handling of missing data and multiplicity. It records zero serious adverse events, zero other adverse events, and zero deaths in each listed treatment group, with 30 at risk in each group. These counts do not establish that no adverse events occurred beyond what was recorded.