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 Use of Sitagliptin for Stress Hyperglycemia or Mild Diabetes Following Cardiac Surgery (NCT01970462), a randomized phase 4 study. The primary outcome is Difference in Fasting Glucose.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01970462 |
| Phase | Phase 4 |
| Condition | Diabetes Mellitus, Type 2, Hyperglycemia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Kathleen Dungan |
| Results posted | Yes |
2. Clinical Question
Population
Patients with stress hyperglycemia or mild diabetes following cardiac surgery. The registry lists type 2 diabetes and hyperglycemia among the conditions.
Intervention
Sitagliptin, described as renally dosed, was planned before hospital discharge and again 6 weeks following discharge.
Comparator
Placebo was planned before discharge and 6 weeks after discharge.
Primary question
What was the difference in mean fasting glucose at 6 weeks post-discharge between the sitagliptin and placebo groups?
The clinical question concerns a postoperative population in which high glucose may occur as stress hyperglycemia or alongside mild diabetes. The intended comparison was between assignment to sitagliptin and assignment to placebo, with fasting glucose at 6 weeks post-discharge as the primary outcome. The registry describes the study as assessing safety and efficacy, but a group-level estimate of the primary outcome is not reported in the registry record.
The reported glucose values cannot answer the comparative question on their own. The record states that group assignment was unavailable from the pharmacy for 3 subjects and that, among the 4 subjects for whom data were available, fasting glucose values were 158, 114, 83, and 237 mg/dl. It does not identify which value belongs to which treatment group. Without that mapping, a treatment-group contrast cannot be estimated from these values.
3. Trial Design
NCT01970462 is listed as a phase 4, randomized, quadruple-masked, parallel-group trial comparing sitagliptin with placebo. The registry records enrollment of 8 and a terminated status. The study start is listed as 2014-01, and primary completion as 2016-08. The record says the study was discontinued early.
The planned population was patients with stress hyperglycemia or mild diabetes following cardiac surgery. Participants assigned to sitagliptin were to receive renally dosed treatment before hospital discharge and 6 weeks following discharge. The placebo group was to receive placebo before discharge and 6 weeks after discharge. The registry does not describe the masking roles, allocation concealment procedures, or details of how treatment was administered beyond these descriptions.
The primary outcome was the difference in mean fasting glucose at 6 weeks post-discharge. The brief study description also identifies a secondary objective: determining whether management of patients with persistent insulin requirements following cardiac surgery differs between those with stress hyperglycemia and those with mild diabetes. Secondary outcome results are not detailed in the available record.
Although random allocation and masking can, in general, help reduce bias in comparisons, they do not overcome the practical consequence of missing treatment assignments and incomplete outcome reporting. The registry does not report an inferential analysis of the primary comparison. Its outcome description explicitly says group-level data cannot be provided because the study ended early and group assignment was unavailable for some subjects. The protocol’s planned sample-size justification, allocation details, and statistical analysis plan are 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.
Before assignment: Enrolled differs from reported because the study was discontinued early and the group number was not available from the pharmacy for 3 subjects. We provided the participant flow for the 5 individuals for whom the group assignment was available. Of 8 total patients enrolled, 4 completed the study, 3 of whom had group assignments available
Overall Study
| Stage | Sitagliptin | Placebo |
|---|---|---|
| STARTED | 1 | 4 |
| COMPLETED | 1 | 2 |
| NOT COMPLETED | 0 | 2 |
Reasons for not completing this period:
| Reason | Sitagliptin | Placebo |
|---|---|---|
| Lost to Follow-up | 0 | 2 |
Analysis population for the primary outcome, as defined in the registry: The study was discontinued early and the group assignment was not available from the pharmacy for 3 subjects. Therefore we are unable to provide group level data for the outcomes. Among the 4 subjects for whom data was available, the fasting 6 week glucose value was 158, 114, 83, 237 mg/dl.
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: Number of patients with at least one dose of study medication
| Characteristic | Unit | Sitagliptin | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 1 | 4 | 5 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 | 2 | 3 |
| Age, Categorical: >=65 years | Participants | 0 | 2 | 2 |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 0 | 3 | 3 |
| Region of Enrollment: United States | participants | 1 | 4 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Difference in Fasting Glucose, measured over 6 weeks.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the difference in mean fasting glucose at 6 weeks post-discharge. Fasting glucose is a measure of blood glucose obtained after a period without food; as a general clinical measure, it can be used to characterize glucose levels at a specified follow-up time. The intended comparison asks whether the average measured level differed between participants assigned to sitagliptin and those assigned to placebo.
The registry lists four fasting glucose values for subjects with available data: 158, 114, 83, and 237 mg/dl. These are individual values, not group means or a reported treatment effect. The record does not map them to treatment assignment, and it does not provide group-specific sample sizes, means, measures of variability, a confidence interval, or a test of the primary comparison. Therefore, the listed values describe observations but do not quantify the difference in mean glucose between the randomized groups.
For a group comparison, the mean summarizes the central level within each group, while an estimated difference expresses the contrast between those group means. A confidence interval, when reported, indicates the precision of that estimated contrast under the analysis assumptions. Neither the contrast nor its precision is available in the registry record. The endpoint’s intended follow-up time is 6 weeks; other endpoint definitions or measurement details beyond the registry description are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome information does not support a comparative estimate of sitagliptin versus placebo. The study was discontinued early, and the registry says treatment assignment was unavailable from the pharmacy for 3 subjects. It also reports that fasting glucose data were available for 4 subjects, with values of 158, 114, 83, and 237 mg/dl. Because the record does not link those values to the randomized groups, it cannot show whether the group means differed or by how much.
These observations should not be interpreted as a treatment effect. They are not a reported group mean, an adjusted estimate, or an unadjusted difference. No confidence interval or p-value for the primary comparison appears in the registry record. Thus, the direction and precision of the intended treatment contrast are unknown from the posted outcome information. The data also do not establish that the groups were similar or different at follow-up.
The registry’s early termination and incomplete group-level reporting limit what can be concluded. Randomization is intended to make treatment groups comparable on average, but an analysis still requires outcome data linked to assignment. When assignment or outcome information is unavailable, the planned comparison cannot be reconstructed from a list of unlabelled individual values. The reason the study was discontinued early is not reported in the registry record, so it should not be inferred.
The record lists enrollment of 8, but that figure does not supply the information needed to evaluate the primary outcome. It does not state how many participants contributed to each treatment group’s endpoint analysis, nor does it report the distribution of missing outcomes by arm. These details matter because missingness can affect both the amount of information available and the comparability of the analyzed groups. The registry does not describe an approach for handling missing data or a defined analysis population.
Safety figures are separately reported by group: serious adverse events affected 0 of 1 at risk in the sitagliptin group and 0 of 4 at risk in the placebo group; other adverse events affected 0 of 1 and 0 of 4 at risk, respectively. These small recorded exposure counts and event summaries are descriptive. They are not a precise comparison of safety, and the registry’s null entries for deaths mean death counts are not reported in the registry record.
Overall, the record documents the trial question, planned comparison, limited glucose observations, and adverse-event counts. It does not provide evidence sufficient to estimate the primary treatment contrast or its uncertainty. No conclusion that sitagliptin did or did not change fasting glucose follows from the listed unassigned values.
9. Statistical Methods Explained
Clinical trial results are most interpretable when the estimand—the quantity the analysis is intended to estimate—is clear. Here, the primary question is framed as a difference in mean fasting glucose at 6 weeks post-discharge between the sitagliptin and placebo groups. In general, an analysis would use measurements linked to assigned treatment to estimate the mean in each group and then contrast those means. The registry does not report those group summaries or the resulting contrast.
What does randomization contribute?
As a general statistical principle, random allocation helps balance prognostic factors between groups on average, reducing confounding in the assigned-treatment comparison. It does not guarantee that every characteristic is exactly balanced, particularly in a small study, and it does not replace the need to preserve treatment labels in the outcome data. In this record, the central obstacle is that group-level primary outcome data are unavailable. The listed glucose values cannot be assigned to the sitagliptin or placebo group from the registry information.
The trial is described as quadruple-masked. Masking can, in general, reduce the influence of expectations on participant reports, treatment delivery, or outcome assessment, depending on who is masked and how the procedures operate. The registry does not identify the masked roles or provide procedural details. Masking also cannot recover unavailable assignments or create a group comparison when the outcome values are not linked to group.
Why are group summaries and uncertainty needed?
A mean describes the central level of a quantitative outcome within a group. A difference in means expresses the contrast between the two groups on the outcome’s measurement scale. For a useful interpretation, the estimate is usually considered together with its uncertainty. A confidence interval is a general statistical tool for expressing a range of values compatible with the data and analysis assumptions; narrower intervals indicate greater precision, while wider intervals indicate less precision. No interval for the primary contrast is reported in the registry record.
A p-value, when used, addresses how compatible the observed data are with a specified null model under the analysis assumptions. It does not measure the size or clinical importance of an effect, and it cannot substitute for an effect estimate and its uncertainty. The registry reports no primary-comparison p-value or inferential analysis. No conclusion about statistical significance can therefore be drawn from the posted glucose values.
How does missing information affect interpretation?
The record states that group assignment was unavailable from the pharmacy for 3 subjects and that fasting glucose data were available for 4 subjects. These statements identify important reporting limitations, but do not specify how missing assignments and outcomes overlap, how missingness is distributed by randomized group, or which participants were included in a particular analysis. A complete-case analysis, for example, would use participants with the required information, but the registry does not state that this approach was used. Nor does it report an imputation method, sensitivity analysis, or other missing-data strategy.
In general, missing data can reduce precision and can bias a comparison if the reasons data are missing are related to treatment assignment or outcome. The direction and size of any such effect cannot be inferred without further information. The available record does not establish why assignments were unavailable, why the study ended early, or whether missingness followed a particular pattern. Those explanations are not reported in the registry record.
What can be said about planning calculations?
Sample-size calculations are planning tools: they describe the amount of information that might be needed under stated assumptions to detect a target effect with a chosen statistical framework. They are not evidence that a treatment effect occurred, and they are not a measure of the probability that this completed study produced a correct result. The registry’s general planning assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of the observed effect. The record does not report the trial’s own sample-size justification. Any planning illustration should therefore be understood as hypothetical, not as observed power.
For this trial, the missing group-level estimate also means the primary effect cannot be examined for precision from the posted outcomes. No recalculated contrast or uncertainty measure is available in the registry record. The sponsor’s analysis is not reported, so there is no sponsor estimate to compare with an unadjusted recalculation. The statistical interpretation is consequently limited to describing the design and the information that the registry records, rather than evaluating a treatment effect.
What about more than one outcome?
The registry lists 4 outcome measures, while no analyses are reported. When a study examines multiple outcomes or multiple time points, testing many hypotheses can increase the chance of at least one apparently notable result under a null model. Multiplicity procedures can address that issue, but they require an analysis plan and enough information to identify the planned tests. The registry does not report whether multiplicity adjustments were planned or applied. The primary outcome remains the stated fasting glucose comparison, but its group-level estimate is unavailable.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 4 outcome measures, but reports 0 analyses. It identifies fasting glucose at 6 weeks post-discharge as the primary outcome. Whether additional outcomes or time points were formally tested, and whether any adjustment for multiple comparisons was planned or performed, is not reported in the registry record. Without a stated analysis plan or reported tests, the effect of multiplicity procedures cannot be assessed.
Missing information is central to interpreting the primary endpoint. The record says the study was discontinued early and group assignment was unavailable from the pharmacy for 3 subjects. It also gives fasting glucose values for 4 subjects, without identifying their treatment groups. The relationship between these assignment gaps and the available outcomes is not described. Group-specific endpoint counts, reasons for missing information, and the method used to handle missingness are not reported in the registry record.
The registry does not specify whether the primary analysis was intended to follow randomized assignment, include only participants with available outcomes, or use another analysis population. It also does not describe imputation, sensitivity analyses, protocol deviations, or exclusions. These omissions prevent assessment of how the available observations were selected and how missing data might affect a treatment comparison.
Because the outcome values are not linked to randomized group and no analysis is reported, neither an intention-to-treat estimate nor a per-protocol estimate can be reconstructed from the record. The available information supports a description of the design and the reporting gaps, but not a group-level treatment effect.
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 |
|---|---|---|---|
| Sitagliptin | 0 | 1 | 0.0% |
| Placebo | 0 | 4 | 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 |
|---|---|
| Sitagliptin | 0 of 1 |
| Placebo | 0 of 4 |
The registry reports adverse events by treatment group. In the sitagliptin group, serious adverse events affected 0 of 1 at risk, and other adverse events affected 0 of 1 at risk. In the placebo group, serious adverse events affected 0 of 4 at risk, and other adverse events affected 0 of 4 at risk. The deaths fields are null for both groups; death counts are not reported in the registry record.
These figures are event summaries for the participants listed as at risk in each group. They do not establish that no adverse events could occur, and they should not be read as a precise estimate of comparative safety. With very limited recorded exposure, an absence of recorded events provides little information about the range or frequency of possible harms. The registry does not give event descriptions beyond the serious and other adverse-event categories, follow-up details for safety, or a formal comparison between groups.
The safety figures are distinct from the primary glucose endpoint. They do not resolve the missing treatment-group mapping for the fasting glucose values, and they do not change the fact that the study was discontinued early. The reason for termination and any safety rationale are not reported in the registry record; neither should be inferred from the event counts.
12. What the Result Does, and Does Not, Mean
The registry establishes that NCT01970462 was a randomized, quadruple-masked comparison of sitagliptin and placebo in patients with stress hyperglycemia or mild diabetes following cardiac surgery. Its primary question concerned the difference in mean fasting glucose at 6 weeks post-discharge. The record also documents that the study ended early and that group-level data for the primary outcome could not be reported.
The glucose values 158, 114, 83, and 237 mg/dl are observations from 4 subjects whose values are not mapped to treatment group. They do not indicate which group had a higher mean, how large any difference was, or whether a difference was compatible with chance under a statistical model. The absence of a reported estimate and confidence interval means the precision of the primary comparison cannot be judged.
This record therefore does not establish that sitagliptin improved, worsened, or had no effect on fasting glucose. It also does not establish equivalence between sitagliptin and placebo. A lack of a reported comparative result is not the same as evidence that the groups had the same outcome. Similarly, the adverse-event counts are limited descriptive records rather than definitive evidence about safety.
The findings that can be stated are narrower: the trial was conducted as a randomized parallel-group study; enrollment was 8; it was terminated; fasting glucose was the primary endpoint; and the registry gives a small set of values without treatment labels. The reasons for early discontinuation and the statistical analysis plan are not reported in the registry record. These limits should remain explicit when discussing the study.
13. Why This Trial Matters Statistically
This trial illustrates a basic requirement for interpreting randomized studies: outcome measurements must be connected to treatment assignment to estimate a between-group effect. A randomized design can support a fair comparison, but the benefit of randomization for inference depends on retaining usable assignment and outcome information. The registry’s individual glucose values cannot answer the comparative question when their group labels are unavailable.
It also shows why an outcome list is not equivalent to a result. The primary endpoint is clearly named, and individual measurements are recorded, but the key statistical quantities—a group contrast and its uncertainty—are absent. A reader cannot infer a treatment effect merely by looking at values without knowing which treatment produced each value. Nor can precision be evaluated without group-level information and an appropriate uncertainty estimate.
Early discontinuation adds context but does not explain the missing information. The registry does not state why the trial ended early or whether the decision was related to recruitment, operational issues, safety, or another reason. Avoiding speculation about that reason is important: the status alone does not establish the circumstances behind termination.
Finally, the adverse-event summaries underline the difference between recording no events in a limited observed group and showing that a treatment is free of risk. The posted counts are descriptive, and deaths are not reported in the registry record. Together, these features make the study statistically instructive while leaving its central treatment comparison 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 most important trial-specific limitation is the absence of group-level primary outcome data. The record attributes this to early discontinuation and unavailable pharmacy group assignment for 3 subjects. Although fasting glucose values are listed for 4 subjects, the treatment group corresponding to each value is not identified. Consequently, the intended difference in mean fasting glucose cannot be estimated from the registry record.
The record does not explain why the study was discontinued early. It also does not report the planned sample-size justification, the detailed statistical analysis plan, group-specific outcome availability, the analysis population, or the approach to missing data. These gaps prevent assessment of whether the reported observations represent the randomized groups as intended and how missing information may have influenced any analysis.
Enrollment is recorded as 8, but the registry does not provide a participant-flow account that links enrollment, treatment assignment, follow-up, and outcome availability. It does not report baseline characteristics or group-level glucose summaries. The four listed glucose values therefore cannot be interpreted as evidence of baseline balance or as a treatment contrast.
Safety reporting is also limited. The adverse-event counts are presented with small at-risk groups, and death counts are not reported in the registry record. Event descriptions, detailed safety follow-up, and reasons for termination are not provided in the available record. These reporting limitations make both efficacy and safety conclusions highly restricted.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Use of Sitagliptin for Stress Hyperglycemia or Mild Diabetes Following Cardiac Surgery — NCT01970462.
- Registry record last updated 2018-06-18; status last verified 2018-05.
- Results first posted 2018-05-17.
- 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
NCT01970462 was a phase 4, randomized, quadruple-masked, parallel-group trial of sitagliptin versus placebo in patients with stress hyperglycemia or mild diabetes following cardiac surgery. The registry lists enrollment of 8 and a terminated status. Treatment was planned before discharge and 6 weeks following discharge, with renally dosed sitagliptin in the intervention group.
The primary endpoint was the difference in mean fasting glucose at 6 weeks post-discharge. The registry reports values of 158, 114, 83, and 237 mg/dl for 4 subjects, but does not map the values to treatment groups. It states that the study ended early and group assignment was unavailable for 3 subjects, preventing group-level outcome reporting. No primary comparison or statistical analysis is reported. Adverse-event counts are recorded by group; death counts are not reported in the registry record.