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 The Beta Cell Responsiveness to Glucose-dependent Insulinotropic Polypeptide (GIP) With and Without Sulfonylurea in Patients With Type 2 Diabetes (NCT00321321), a non-randomized phase 2 study. The primary outcome is Insulin Secretion.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00321321 |
| Phase | Phase 2 |
| Condition | Diabetes Mellitus, Type 2 |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University Hospital, Gentofte, Copenhagen |
| Results posted | Yes |
2. Clinical Question
Population
The registry record identifies patients with type 2 diabetes as the population of interest. It records enrollment of 12 participants, but does not report further participant characteristics in the primary outcome description. Details such as baseline insulin secretion, disease duration, or other eligibility features are not reported in the registry record.
Intervention
The listed intervention is sulfonylurea (SU), a drug intervention. The investigators' stated hypothesis is that closing beta-cell K-ATP channels with SU may restore the insulinotropic effect of glucose-dependent insulinotropic polypeptide (GIP). The registry record does not describe the SU regimen or the procedures used to assess responsiveness.
Comparator
The record describes a non-randomized, single-group study and does not list a like-for-like control group. The title frames the question as responsiveness to GIP with and without SU, but the registry entries do not provide a separate comparator group or a comparative analysis.
Primary question
The registered primary outcome is insulin secretion, described using area under the curve (AUC) and insulin secretion rate over 0 - 90 minutes. The scientific question is whether beta-cell insulin secretion in this population is responsive to GIP in the context of SU. The registry record does not report numerical outcome results, so the size, direction, and precision of any observed response cannot be assessed from the record.
3. Trial Design
This is a completed phase 2 study with non-randomized allocation, no masking, and a single-group model. The registry record reports enrollment of 12 participants with type 2 diabetes. It lists sulfonylurea as the drug intervention and identifies insulin secretion as the primary outcome. The study dates recorded are a start in 2006-05 and primary completion in 2007-03.
A single-group design does not establish a randomized, concurrent contrast between SU and a control condition. The title refers to responsiveness to GIP with and without SU, but the registry record does not specify how those conditions were arranged or provide a control-group result. The record therefore does not support treating the study as a randomized comparison or interpreting its design as if treatment allocation created comparable groups.
The stated rationale is mechanistic: investigators hypothesized that impaired insulinotropic action of GIP might be related to inadequate sensitization and ATP-induced closure of beta-cell K-ATP channels. They proposed that closing the channels through SU might restore GIP's insulinotropic effect. This is the investigators' hypothesis, not a reported finding. Details of the protocol, SU administration, GIP administration, timing of assessments, and analysis plan are not reported in the registry record.
The record is marked completed, but numerical results for the primary outcome are not reported. It lists one outcome measure and zero analyses. Thus, the available record identifies the study question and broad design, but does not provide the estimates needed to evaluate the observed insulin secretion response. The sample-size planning illustrations, where applicable, should be understood as calculations based on an observed effect, not as the original design justification or as evidence of statistical power achieved by this study.
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 | Sulfonylurea |
|---|---|
| STARTED | 12 |
| COMPLETED | 12 |
| NOT COMPLETED | 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 | Sulfonylurea |
|---|---|---|
| Participants analysed | 12 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 |
| Age, Categorical: >=65 years | Participants | 1 |
| Age, Continuous | years | 55 (SD 7.6) |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 8 |
| Region of Enrollment: Denmark | participants | 12 |
6. Primary Endpoint
The registry lists the primary outcome as Insulin Secretion, measured over 0 - 90 minutes.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | pmol/l * 90 minutes |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled insulin secretion. Its registered unit is pmol/l * 90 minutes, and the description specifies area under the curve (AUC) and insulin secretion rate over 0 - 90 minutes. These are ways to characterize insulin secretion across a measurement interval: an AUC reflects the accumulated response over that interval, while a secretion rate describes the rate of insulin release as represented by the study's measurement method.
In general, a time-based measure can be useful when the scientific question concerns a physiological response unfolding over an interval rather than a single isolated measurement. AUC can capture the overall magnitude of a response, while a rate measure can describe its pattern. The two descriptions should not be assumed to be interchangeable, and the registry record does not provide further operational definitions, calculation details, or a reported value for either.
The outcome is relevant to the stated hypothesis because the investigators are interested in whether GIP has an insulinotropic effect in the setting of SU. However, an endpoint's relevance does not establish that a response was observed. Numerical values, a measure of variability, and an analysis estimate are not reported in the registry record. The timing is given as 0 - 90 minutes, but the record does not describe the schedule or method of measurement within that interval.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives the study's rationale, broad design, and primary outcome definition, but it does not report the primary outcome results. The record lists zero analyses, and no numerical insulin secretion estimate, uncertainty interval, or test result is reported in the registry record. Consequently, the direction and size of the observed response cannot be described from these data. Nor can the precision of an estimate be judged.
The study was non-randomized and single-group. Its title mentions responsiveness to GIP with and without SU, but the registry record does not report a separate control-group result or a direct between-condition estimate. The design information therefore does not support reading the record as a randomized comparison. Even if a within-person or condition-based assessment was performed, the registry record does not describe it; the comparison method and its results are not reported in the registry record.
The investigators' hypothesis is not a result. They proposed that impaired GIP insulinotropic action may relate to inadequate sensitization and ATP-induced closure of beta-cell K-ATP channels, and that SU-related channel closure might restore the effect. This rationale explains the scientific question, but does not show that SU altered insulin secretion or that any alteration was attributable to SU. A hypothesis can guide outcome selection without serving as evidence that the predicted effect occurred.
General statistical interpretation depends on the estimate and its uncertainty, not solely on whether a test crosses a threshold. A confidence interval, when reported, indicates the range of values compatible with the data under the analysis assumptions; its width reflects precision. Here, no estimate or interval is reported, so neither magnitude nor uncertainty can be appraised. The record also does not provide an outcome distribution or dispersion measure that would help readers understand participant-to-participant variability.
The enrollment count of 12 is a design fact, not evidence by itself that the study was adequately powered or that an effect was absent or present. The registry's planning illustrations are described as computed from an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They are explicitly not the trial's own design. Such illustrations are planning scenarios, not observed power, and cannot fill the gap left by unreported outcome analyses.
Overall, the posted record documents a completed mechanistic study question and a defined insulin secretion outcome, but not the result needed to answer that question. No efficacy conclusion or conclusion about the presence or absence of an effect follows from the missing numerical outcome data. The appropriate interpretation is that the registry record does not report the primary result.
9. Statistical Methods Explained
Statistical methods determine how measurements are converted into estimates and how uncertainty is represented. The registry record identifies the study as non-randomized and single-group, and lists zero analyses. It does not report a statistical analysis plan, an effect estimate, or a test result. The concepts below explain how such information would generally be interpreted; they do not describe unreported procedures as if they were used in this study.
What does a single-group design imply?
In general, a single-group study can describe measurements in the participants observed, but it does not by itself provide the protection against confounding that random assignment can offer in a concurrent comparison. If measurements are made under more than one condition, interpretation depends on how conditions are defined, how the order and timing are handled, and how within-participant changes are analyzed. Those details are not reported in the registry record. The title's reference to GIP with and without SU does not establish the specific design of a condition contrast.
Without a clearly described comparison, an observed change cannot automatically be attributed to the intervention. Other explanations may include time effects, measurement variability, or differences in the circumstances of assessment. These are general interpretive concerns, not claims about what occurred in this study. The record's non-randomized allocation and single-group model mean the results, if reported elsewhere, would need to be interpreted in light of the actual comparison and protocol.
What would an estimate and confidence interval add?
In general, an estimate describes the observed magnitude and direction of an outcome or contrast. A confidence interval describes uncertainty around that estimate under the statistical model and assumptions used. A narrow interval is more precise than a wide one, while an interval spanning effects in different directions may leave the interpretation uncertain. Statistical significance alone does not communicate the size or practical relevance of an effect. For this record, no estimate or confidence interval for insulin secretion is reported, so the observed magnitude and precision cannot be evaluated.
The outcome description includes AUC and insulin secretion rate. For an AUC, a statistical analysis might summarize the response over the specified interval; for a rate, an analysis might summarize the measured rate or its change. The appropriate method depends on the measurement schedule, distribution, and study design. None of those analytic details is reported in the registry record, and the outcome description does not supply a numerical result or dispersion statistic.
Why does variability matter?
General statistical inference depends on variability as well as the estimate. Measurements can differ between participants, and repeated measurements may also vary within a participant. A summary without a measure of dispersion cannot show whether responses were similar or highly variable. The registry record's primary outcome entry does not report dispersion. Consequently, readers cannot determine how consistent the insulin secretion measurements were or how much uncertainty would be expected around a group summary.
Model assumptions also matter. A normal approximation is one method used in some planning calculations, but its suitability depends on the outcome and analysis. The planning assumptions listed for the illustrations specify a normal approximation; this does not establish that the trial's primary outcome was analyzed using that approach. The analysis method for the observed endpoint is not reported in the registry record.
How should the planning illustrations be read?
The registry record describes sample-size planning illustrations as based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the illustrations are not the trial's own design. They should therefore be read as hypothetical planning calculations under stated assumptions, not as a record of the study's enrollment target or analysis plan. The effect to detect is framed as a stated fraction of the observed effect, but the primary outcome analysis needed to identify that observed effect is not reported in the registry record.
Planning calculations do not establish observed power. In general, observed power calculated after a study is closely tied to the estimated effect and does not replace reporting the estimate and its uncertainty. The illustrations cannot show whether the study had adequate power for its original question, since the original sample-size justification is not reported in the registry record. The record also does not report a protocol-based target sample size or a prespecified clinically meaningful effect.
What can be concluded from the posted analysis information?
The registry record lists zero analyses. This means the record does not provide statistical results to evaluate, not that an analysis necessarily was or was not performed outside the registry. The analysis population, handling of missing observations, model specification, and any adjustment for covariates are not reported in the registry record. A statistical interpretation therefore has to stop at the design and endpoint description. General methods can clarify what information matters, but cannot recover absent estimates or establish which procedure investigators used.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies one outcome measure, titled insulin secretion, and describes AUC and insulin secretion rate. It does not report an analysis plan that clarifies whether these were treated as separate analyses, as complementary summaries of a single outcome, or in another way. The record lists zero analyses, so no multiplicity adjustment or hierarchy of outcomes is reported in the registry record.
In general, testing multiple outcomes, time points, or contrasts can increase the chance of a chance-positive finding if results are selected or interpreted without accounting for that multiplicity. A prespecified outcome hierarchy or adjustment method can help address this issue. The registry record does not report whether such procedures were planned or used. It is therefore not possible to assess the handling of multiplicity from the available analysis information.
Missing-data handling is also not reported in the registry record. The primary outcome population field contains no description, and the record does not explain whether all enrolled participants contributed endpoint measurements, how incomplete measurements were handled, or what assumptions underlie any missing-data method. No imputation procedure or sensitivity analysis is reported. Those omissions matter because the analyzed participants and assumptions about missing measurements can affect both an estimate and its uncertainty.
The record does not describe an analysis population, such as a prespecified set of participants or measurements. The enrollment count of 12 alone does not establish which observations entered a primary analysis. Since the outcome results are not reported, readers cannot assess whether missingness or analysis-population choices influenced the findings. These are information gaps in the registry record, rather than evidence that data were missing or that a particular method was used.
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 |
|---|---|---|---|
| Sulfonylurea | 0 | 12 | 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 |
|---|---|
| Sulfonylurea | 0 of 12 |
The serious adverse event summary lists the Sulfonylurea group with 12 at risk and zero affected by serious events. The separate other-event fields list 12 at risk and zero affected. No serious event terms are listed. These figures describe what is recorded in the registry adverse-event summary; they do not provide a detailed event narrative or a measure of comparative risk.
The study is single-group and does not provide a like-for-like control comparison in the registry record. The zero counts therefore cannot establish a relative safety difference between SU and an alternative. A count of zero affected participants in the recorded categories also does not establish that no event of any kind occurred, or that the intervention has no safety risks. Interpretation depends on event definitions, collection procedures, observation duration, and completeness of reporting, which are not described in the registry record.
The adverse-event figures should be read as registry reporting, not as a complete characterization of safety. The record does not report event severity beyond the serious-event category, timing, relationship assessments, or additional clinical detail. The enrollment and at-risk counts are reported as given and should not be combined into a broader participant total.
12. What the Result Does, and Does Not, Mean
This registry record matters as a description of a focused physiological question: whether beta-cell insulin secretion in patients with type 2 diabetes responds to GIP in the context of SU. It records a completed phase 2, non-randomized, single-group study and specifies insulin secretion over 0 - 90 minutes as the primary outcome. The investigators' proposed mechanism links impaired GIP action to beta-cell K-ATP channel closure and proposes SU as a way to address that mechanism.
What the record does not provide is the primary outcome result. No numerical AUC or insulin secretion rate, estimate of a contrast, measure of variability, or uncertainty interval is reported. The registry record lists zero analyses. As a result, the record cannot establish the direction or magnitude of any response, the consistency of responses, or the precision of an estimate. It also cannot show whether the proposed mechanism was supported by the observed data.
The design description limits comparative interpretation. Non-randomized allocation and a single-group model do not constitute a randomized control comparison. Although the title refers to responsiveness with and without SU, the registry entries do not report a separate control group or the method and result of a condition-based comparison. Without those details, readers should not infer a causal treatment effect from the title or hypothesis.
The safety summary records zero participants affected in its serious and other event fields, among the stated at-risk counts. That is a description of registry reporting, not proof that risks are absent or evidence of comparative safety. The record does not give the broader detail needed to characterize safety fully.
In short, this entry documents the scientific rationale, intervention category, study design, and registered outcome, but not the numerical findings required to answer the primary question. Its planning illustrations cannot substitute for results or establish observed power. Any conclusion about whether insulin secretion changed, and by how much, is not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable because its mechanistic question is more specific than a broad comparison of treatments: it concerns beta-cell responsiveness to GIP and the proposed role of SU-related K-ATP channel closure. That focus makes the definition and timing of the insulin secretion outcome central to interpretation. The registry identifies AUC and insulin secretion rate over 0 - 90 minutes, but does not report the estimates needed to relate the measurement to the proposed mechanism.
The design also illustrates why a study title should not be mistaken for a comparison structure. The title names responsiveness with and without SU, while the registry identifies non-randomized allocation and a single-group model. A valid interpretation depends on the actual conditions, measurement sequence, and analysis; these details are not reported in the registry record. The question may be scientifically focused, but the causal strength of any comparison cannot be judged from the title alone.
For statistical readers, the key distinction is between a hypothesis, a design, and a result. The record supplies the hypothesis and broad design description, while the numerical outcome analysis is absent. This limits what can be learned about effect magnitude and precision, regardless of the biological plausibility of the proposed mechanism. It also emphasizes why registry outcome definitions are useful but do not replace complete reporting of estimates, variability, and analysis methods.
The record further distinguishes planning illustrations from the original trial design. Calculations based on an observed effect can serve as hypothetical planning scenarios, but they do not tell readers what sample-size rationale investigators used before conducting the study. Since the outcome results and original justification are not reported, neither power for the original question nor the evidence for the stated hypothesis can be evaluated from this entry.
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 trial-specific limitation for interpretation is the absence of numerical primary outcome results. The registry describes insulin secretion using AUC and insulin secretion rate, but does not report either result, a dispersion measure, an effect estimate, or an uncertainty interval. The record lists zero analyses. This prevents assessment of effect size, direction, precision, and variability.
The design is recorded as non-randomized and single-group, and no like-for-like control comparison is listed. The title's reference to GIP with and without SU is not accompanied by a description of how those conditions were assigned, ordered, or analyzed. The registry record therefore does not establish a randomized contrast or provide enough detail to evaluate a within-participant contrast.
Participant characterization is limited to the condition and enrollment count. Further baseline details and eligibility criteria are not reported in the registry record. The primary outcome population is not described, and the record does not explain whether all enrolled participants contributed measurements. The timing and method of outcome collection within 0 - 90 minutes are also not specified beyond the timeframe itself.
The protocol, SU regimen, GIP procedures, analysis plan, missing-data approach, and any multiplicity procedures are not reported in the registry record. The record does not give a sample-size justification for the trial itself. Planning illustrations are described as based on an observed effect and are not the trial's own design; without the primary analysis result, they cannot clarify the original design rationale or observed precision.
Finally, the safety summary is limited to the reported affected counts and at-risk counts. Detailed event descriptions, observation duration, and event-collection procedures are not reported in the registry record. These limitations concern what the registry entry documents and do not establish what investigators may have collected outside it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Beta Cell Responsiveness to Glucose-dependent Insulinotropic Polypeptide (GIP) With and Without Sulfonylurea in Patients With Type 2 Diabetes — NCT00321321.
- Registry record last updated 2015-07-16; status last verified 2008-09.
- Results first posted 2008-10-02.
- 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 record describes NCT00321321, a completed phase 2 study concerning beta-cell responsiveness to GIP with and without sulfonylurea in patients with type 2 diabetes. It reports non-randomized allocation, no masking, a single-group model, and enrollment of 12 participants. Sulfonylurea is listed as the drug intervention.
The primary outcome is insulin secretion, with AUC and insulin secretion rate described over 0 - 90 minutes and a registered unit of pmol/l * 90 minutes. The investigators' hypothesis proposes that SU-related closure of beta-cell K-ATP channels may restore GIP's insulinotropic effect. Numerical primary outcome results are not reported in the registry record, and the record lists zero analyses.
The adverse-event summary records zero affected participants in the serious and other event fields, with 12 at risk in each field. The available entry defines the question and broad design but does not provide the statistical results needed to assess the primary outcome.