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 Apelin Levels and G212A Polymorphism of Apelin Receptor (APJ) (NCT01121172), a registered phase not stated study. The primary outcome is Serum Apelin Levels.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01121172 |
| Phase | Phase not stated |
| Condition | Obesity, Insulin Resistance, Diabetes Mellitus Type 2 |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 180 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Aristotle University Of Thessaloniki |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns children and adolescents described as obese, alongside a lean group. The registry reports enrollment of 180 participants, with 90 in each group. Obesity in the obese group was defined according to International Obesity Task Force criteria. Further details about eligibility, recruitment, or participant characteristics are not reported in the registry record.
Intervention
No treatment intervention is described. The study aim was to investigate serum apelin levels and their possible association with the G212A polymorphism of the apelin receptor. Serum apelin was measured in a fasting state; the registry does not report details of the laboratory assay or how the polymorphism was assessed.
Comparator
The record identifies obese and lean groups. It does not give a description of the lean group, and allocation is not stated. The comparison is not described as randomized or as a like-for-like controlled comparison. Other characteristics that might distinguish the groups are not reported in the registry record.
Primary question
The primary outcome is serum apelin level, measured in ng/ml. The study asks about levels in obese children and adolescents; its broader stated aim is to examine a possible association with the G212A receptor polymorphism. A secondary outcome concerns the frequency of that polymorphism in obese children and adolescents. The registry record does not report the measured levels, polymorphism frequencies, or an estimate of association, so the direction and precision of any observed relationship cannot be assessed.
3. Trial Design
The registry describes a completed study sponsored by Aristotle University Of Thessaloniki. The listed start date is 2010-05, the primary completion date is 2012-06, and enrollment is 180. Participants are divided into an obese group and a lean group, with 90 participants listed in each. The obese group is described as meeting International Obesity Task Force criteria; the lean group has no description in the record.
This is not presented as a randomized comparison. Allocation is not stated, and the registry record cautions that the arms are not a like-for-like control comparison. The nature of the study is listed as “other.” No treatment allocation, masking, recruitment method, or prospective protocol details are reported in the registry record. The available description therefore supports reading this as a comparison of participant groups, not as a randomized treatment-effect trial.
The primary outcome is serum apelin level, expressed in ng/ml, and the secondary outcome is the frequency of the G212A polymorphism of the apelin receptor in obese children and adolescents. The registry lists two outcome measures and two analyses, but does not report the methods or numerical results for those analyses. In particular, it does not state which statistical tests were used, whether covariates were included, or how the groups were handled in the analysis.
The primary outcome timeframe refers to measurement on the first day after enrollment following an overnight fast. Its wording also includes “at approximately 8:00 pm in the morning,” which is unclear. Whether this wording reflects a time-of-day error or another intended timing description is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Obese | Lean |
|---|---|---|
| STARTED | 90 | 90 |
| COMPLETED | 90 | 90 |
| 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 | Obese | Lean | Total |
|---|---|---|---|---|
| Participants analysed | 90 | 90 | 180 | |
| Age, Continuous | years | 11.6 (2.6 to 16.5) | 11.7 (3.3 to 17.8) | 11.6 (2.6 to 17.8) |
| Sex: Female, Male: Female | Participants | 56 | 47 | 103 |
| Sex: Female, Male: Male | Participants | 34 | 43 | 77 |
| Region of Enrollment: Greece | participants | 90 | 90 | 180 |
6. Primary Endpoint
The registry lists the primary outcome as Serum Apelin Levels, measured over First day after enrollment and after 8-hours of night fasting, at approximately 8:00 pm in the morning.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | ng/ml |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is serum apelin level, measured in ng/ml. The registry says that apelin was measured in participants’ serum in a fasting state. It specifies a median as the summary measure and a full range as the accompanying measure of spread. These choices describe the center and extent of the observed measurements without assuming that values follow a symmetric, bell-shaped distribution.
In general, the median is the middle value when observations are ordered. It is less affected by unusually high or low observations than the arithmetic mean, which can make it a useful summary when measurements are skewed. The full range gives the lowest and highest observed values, so it conveys the overall span but is sensitive to extreme observations. It does not show how densely values are distributed between those endpoints.
Measuring apelin addresses the study’s stated interest in its levels among obese children and adolescents and its possible relationship with the apelin receptor polymorphism. The registry does not report the median, the full range, or a group contrast for serum apelin. The assay method, laboratory quality procedures, and handling of values below or above any assay limits are also not reported in the registry record. Consequently, the endpoint’s measurement scale and stated summaries are known, but the observed distribution and the precision of any group comparison cannot be evaluated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a question about serum apelin levels and the G212A polymorphism of the apelin receptor, with obese and lean participant groups. It does not report the outcome values needed to describe what the study observed. There are no serum apelin medians or ranges, no polymorphism frequencies, and no reported estimate of an association between apelin and the polymorphism. The direction and size of any group difference or association are therefore not available from the registry record.
Precision cannot be assessed either. A confidence interval, when reported, describes a range of values compatible with the data under the analysis assumptions; its width indicates how precisely an effect has been estimated. No confidence intervals or other uncertainty measures for the primary or secondary outcomes are reported in the registry record. A p-value or test result for these outcomes is also not reported. Without the estimates and their uncertainty, it is not possible to determine how much the data might distinguish among different possible values.
The enrollment count is 180, divided into groups of 90. Those counts describe the registry’s listed group sizes, not the amount of information available for every analysis. The number of participants with a valid apelin measurement or polymorphism result, and the handling of incomplete data, are not reported in the registry record. Thus the analysis-specific denominators cannot be confirmed.
The group comparison also requires caution because allocation is not stated and the registry does not characterize the lean group. The record explicitly cautions that the arms are not a like-for-like control comparison. Differences between these groups, if present, could not automatically be attributed to obesity alone; other group characteristics and any adjustment for them are not reported. This is a limitation of interpretation, not evidence that a particular source of bias occurred.
The record lists the study as completed, with start and primary completion dates of 2010-05 and 2012-06. Completion status does not supply the missing endpoint results or establish how the analysis was conducted. In general, statistical conclusions depend on the observed estimates, their uncertainty, the analysis population, and the assumptions behind the chosen method. Those details are not reported for these outcomes, so the registry supports describing the study question and design features, but not drawing a quantitative conclusion about its findings.
9. Statistical Methods Explained
The registry specifies a median and full range for serum apelin. In general, a median summarizes the center of a set of measurements by its ordered position, while the full range describes the span from the lowest to the highest value. These summaries can be informative when a measurement is skewed or contains extreme observations. The median is relatively resistant to extreme values; the range is not, and it does not describe the concentration of observations within the span. The registry does not report the actual median or range, so these summaries cannot be interpreted for the participants in this study.
Comparing two groups requires more than stating their separate summaries. An analysis might estimate a difference between group distributions, or use a model that accounts for participant characteristics. In general, the chosen method should suit the measurement scale and distribution, and its assumptions should be considered. The registry lists two analyses but does not name the tests or models, state whether estimates were adjusted, or report a group contrast. It is therefore not possible to identify the inferential method or evaluate its assumptions from the registry record.
The secondary outcome concerns the frequency of the G212A polymorphism. In general, a frequency analysis describes how often a genetic variant is observed in a defined group. Comparing frequencies may call for methods suited to categorical data; the choice depends on the data and analysis plan. The registry does not report the observed frequencies, genotype categories, comparison method, or any estimate of association with apelin levels. No particular method should be inferred from the fact that this outcome is listed.
In general, over-dispersion occurs when variation in data is greater than a statistical model expects. If a model assumes less variability than the data contain, its uncertainty estimates can be too small and its tests can appear more conclusive than warranted. This concept may matter in analyses of counts or repeated observations, but the registry does not state that either issue arose in this study or identify a model for which over-dispersion was assessed. It is therefore background on a statistical issue, not a claim about this analysis.
The registry’s sample-size assumptions describe a planning illustration computed from the observed effect, not the trial’s own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is defined as a stated fraction of the observed effect. In general, a planning calculation estimates the group size that might be needed to detect an effect under specified assumptions. It is not a count of observed participants and is not evidence that the study had a particular probability of detecting its result. The registry record does not report a sample-size justification used to design this study. Any planning illustration based on an observed effect should be read as a hypothetical planning exercise, not as observed power.
In general, a confidence interval conveys uncertainty around an estimate, while a test result evaluates compatibility with a specified null hypothesis under its assumptions. Neither replaces the estimate itself: a small p-value does not convey the magnitude of a difference, and a non-small p-value does not establish that groups are equivalent. For this study, the registry record does not report outcome estimates, confidence intervals, or p-values, so these distinctions explain how results would be read but cannot be applied to a numerical finding.
Statistical methods also depend on the analysis population and missing-data handling. The enrollment count does not establish how many participants contributed to each endpoint. In general, excluding participants with missing measurements can change the analyzed group, while methods that use incomplete records make additional assumptions. The registry does not state the number with available outcome data, the reasons for missingness, or the method used to handle missing data. It also does not describe prespecified analysis populations, covariate adjustment, interim analyses, or a detailed statistical plan. These items are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The record lists two outcome measures: serum apelin levels as the primary outcome and frequency of the G212A polymorphism as a secondary outcome. It also lists two analyses. The registry does not explain how those analyses correspond to the outcomes, whether additional comparisons were made, or whether a multiplicity procedure was used. When several outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase. In general, a prespecified analysis hierarchy or an adjustment method can help clarify how multiple results should be interpreted. Whether either approach was used is not reported in the registry record.
Missing-data information is also limited. The registry reports enrollment and group sizes, but does not report how many participants had a usable serum measurement or polymorphism result. Reasons for missing measurements, exclusions after enrollment, and methods for handling incomplete records are not reported. The listed group sizes should therefore not be assumed to equal the analysis-specific sample sizes.
The analysis populations are not described. The registry does not say whether all enrolled participants were included in each analysis or whether eligibility for analysis depended on having particular measurements. No interim analyses or stopping rules are reported in the registry record. Without these details, the analysis process cannot be fully reconstructed, and the potential effects of missingness or multiple testing cannot be assessed from the record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Obese | 0 | 90 | 0.0% |
| Lean | 0 | 90 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Obese | 0 of 90 |
| Lean | 0 of 90 |
The registry lists 90 participants at risk in each group for serious adverse events and reports zero affected in each group. It also lists 90 at risk and zero affected in each group for other adverse events. These are the counts in the registry record; they do not establish that every participant was observed for the same duration or that every possible event was captured.
No serious adverse-event terms are listed. Deaths are recorded as null rather than as a numerical count, so deaths should not be read as zero. The registry does not explain the safety-collection procedures, event definitions, follow-up period for safety, or whether the listed counts reflect complete reporting. In general, a count of zero recorded events is not proof that no event occurred; interpretation depends on monitoring and reporting completeness. The record does not provide enough detail to assess those processes.
This study is described as a comparison of obese and lean groups, not a randomized treatment comparison. The safety counts therefore do not estimate the safety of a treatment. They should be read narrowly as the adverse-event counts entered in the registry, with the limits of the record in mind.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed study enrolled 180 participants in obese and lean groups and set out to examine serum apelin levels and the G212A polymorphism of the apelin receptor. It identifies serum apelin as the primary outcome and the polymorphism frequency as a secondary outcome. It does not report the numerical results for either outcome. As a result, the record cannot establish whether the groups differed in apelin levels, how common the polymorphism was, or whether the proposed association was observed.
It also does not provide estimates or uncertainty measures that would show the size and precision of any finding. The absence of results in the registry record should not be interpreted as evidence of no difference or no association. It means that the relevant outcome findings are not reported there.
The design limits causal interpretation. The registry does not state allocation, and it cautions that the groups are not a like-for-like control comparison. A comparison between these groups, even if its numerical results were available, would not by itself establish that group status caused a difference. Participant characteristics, measurement procedures, and adjusted analyses that could help contextualize a comparison are not reported in the registry record.
The study’s stated motivation refers to apelin and possible links with metabolic conditions, but the listed outcomes do not amount to evidence of early detection or prevention. Such implications cannot be established from the study aim alone. The registry record also does not report a clinical decision threshold, validation work, or follow-up outcome relevant to those claims. The appropriate reading is limited to the research question, group structure, endpoint definition, and the information actually recorded about results and safety.
13. Why This Trial Matters Statistically
Statistically, this record is useful for distinguishing a clearly stated research question from a fully interpretable result. It identifies a primary measurement, serum apelin in ng/ml, and a secondary genetic-frequency outcome. It also specifies that the primary measurement is summarized by a median and full range. These details clarify the intended outcomes and their summaries even though their numerical findings are not reported.
The record also makes the comparison structure important to interpretation. There are obese and lean groups, but allocation is not stated and the record cautions that the groups are not a like-for-like control comparison. That distinction helps prevent a group association from being treated as a randomized treatment effect. It also highlights why clear descriptions of eligibility, group characteristics, and adjustment methods matter when interpreting observational comparisons.
Another statistical lesson is that enrollment is not a substitute for analysis detail. The record lists 180 participants and 90 in each group, but does not state the endpoint-specific number analyzed, the handling of missing measurements, or the statistical tests. Without estimates and uncertainty measures, the magnitude and precision of any result cannot be evaluated. The listed sample-size assumptions are a planning illustration based on an observed effect, not a description of the original design or observed power.
Finally, the safety entries illustrate the need to distinguish zero recorded events from unreported information. Counts of zero affected participants appear for serious and other adverse events, while deaths are null. Reading these entries carefully avoids treating an unreported count as a confirmed zero. Together, these features make the record useful for understanding how design, reporting completeness, and statistical interpretation are connected.
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 outcome reporting is the central limitation: serum apelin medians and ranges, polymorphism frequencies, and statistical comparisons are not reported in the registry record. There are also no confidence intervals or p-values to characterize uncertainty. This prevents quantitative interpretation of the primary and secondary outcomes.
The comparison groups are incompletely described. The obese group is defined using International Obesity Task Force criteria, but the lean group description is blank. Allocation is not stated, and the record cautions that the groups are not a like-for-like control comparison. Participant characteristics, recruitment details, and any adjustment for differences between groups are not reported. These gaps limit assessment of comparability and possible confounding.
Measurement and analysis details are also absent. The registry does not identify the assay, laboratory quality procedures, genetic assessment method, statistical tests, or analysis populations. It does not report endpoint-specific denominators, missing-data methods, or whether the stated analyses were prespecified. The primary outcome timeframe includes the unclear wording “at approximately 8:00 pm in the morning,” so the intended timing cannot be determined from the record.
Safety interpretation is limited by the lack of detail about event definitions, monitoring, and follow-up. Although zero affected participants are listed for adverse-event categories, deaths are null and the completeness of safety reporting is not described. These limitations concern what can be established from the registry record; they do not establish that particular methods were absent from the underlying study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Apelin Levels and G212A Polymorphism of Apelin Receptor (APJ) — NCT01121172.
- Registry record last updated 2016-05-19; status last verified 2016-04.
- Results first posted 2016-05-19.
- 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.
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18. Record Summary
NCT01121172 is a completed study sponsored by Aristotle University Of Thessaloniki. The listed start date is 2010-05, primary completion date is 2012-06, and enrollment is 180. The study concerns obese children and adolescents and a lean comparison group, with 90 participants listed in each group.
The primary outcome is serum apelin level in ng/ml, summarized by median and full range. The secondary outcome is frequency of the G212A polymorphism of the apelin receptor in obese children and adolescents. The registry record does not report the outcome values, statistical tests, or uncertainty estimates. It does not state allocation and cautions that the arms are not a like-for-like control comparison.
The record lists zero affected participants for serious and other adverse events in each group, while deaths are null. The safety reporting procedures are not described. Overall, the registry gives the study question and basic group structure, but does not provide the results or analysis details needed to assess the observed associations.