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 Effect of Sitagliptin in Type 2 Diabetes Mellitus With Inadequate Glycemic Control (MK0431-118) (NCT00832624), a non-randomized phase 4 study. The primary outcome is Change From Baseline in HbA1c (Hemoglobin A1c) at Week 18.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00832624 |
| Phase | Phase 4 |
| Condition | Diabetes Mellitus Non-insulin-dependent |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
The intended population was adult patients with type 2 diabetes and inadequate glycemic control. The registry lists the condition as non-insulin-dependent diabetes mellitus. Further eligibility details, including how inadequate control was defined, are not reported in the registry record.
Intervention
The study intervention was sitagliptin. The registry’s intervention and arm descriptions do not specify a dose; a 100 mg dose appears in the adverse-event grouping title. The record does not provide enough information to treat that grouping label as a complete description of the intervention regimen.
Comparator
There was no separate comparator group. The study is recorded as single-group, nonrandomized, open-label, and non-placebo-controlled. The clinical question therefore concerned change during sitagliptin treatment, rather than a randomized comparison between sitagliptin and another treatment or placebo.
Primary question
The planned primary endpoint was change from baseline in HbA1c at Week 18. HbA1c is a laboratory measure of the percentage of hemoglobin with glucose bound to it. The study also sought to assess safety and tolerability. However, the registry states that the study was terminated early, no laboratory tests were performed, and no outcome data were collected. Thus, the record does not answer whether HbA1c changed or what safety findings occurred.
3. Trial Design
This was a Phase 4 study of sitagliptin in adults with type 2 diabetes and inadequate glycemic control. The registry describes it as open-label, non-placebo-controlled, nonrandomized, and single-group, with no masking. It lists sitagliptin as the intervention and gives an enrollment value of 10. That listing does not establish how many participants completed treatment or contributed outcome data: the registry explicitly says that no data were analyzed for the primary outcome.
The planned primary endpoint was change from baseline in HbA1c at Week 18. The registry also describes safety and tolerability as objectives. The record lists the study start as 2008-11-26 and primary completion as 2009-09-02, and its status is terminated. It states that the study ended early, no laboratory tests were performed, and no outcome data were collected. The reason for termination is not reported in the registry record.
Because there was only one group and no random allocation or comparator, the design was not a like-for-like controlled comparison. Even if before-and-after values had been available, a change within one group would not by itself estimate how outcomes would have differed under another treatment. In this case, no such values were collected, so the planned within-group change cannot be estimated either. The record does not report a statistical analysis plan, a sample-size justification, or further details of treatment duration or follow-up beyond the planned Week 18 endpoint.
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: Patients between 18 and 75 years old with type 2 diabetes mellitus (T2DM) and inadequate glycemic control, who had not taken medication for at least 2 months or using a single drug for diabetes mellitus were enrolled in the study. Insulin-dependent patients were excluded from the study.
Overall Study
| Stage | Sitagliptin 100 mg |
|---|---|
| STARTED | 10 |
| COMPLETED | 0 |
| NOT COMPLETED | 10 |
Reasons for not completing this period:
| Reason | Sitagliptin 100 mg |
|---|---|
| Study Terminated | 10 |
Analysis population for the primary outcome, as defined in the registry: The study was terminated early and no data were analyzed for this outcome.
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 | Sitagliptin 100 mg |
|---|---|---|
| Participants analysed | 10 | |
| Age, Continuous | years | 51.7 (SD 14.0) |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 1 |
| Region of Enrollment: Brazil | participants | 10 |
| Weight | Kilograms | 71.59 (SD 11.55) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in HbA1c (Hemoglobin A1c) at Week 18, measured over Baseline and Week 18.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
HbA1c is the percentage of hemoglobin with glucose bound to it, as described in the registry. The planned endpoint was change from baseline in this measure at Week 18. In general, HbA1c is used as a laboratory indicator of glycemic control over time; a baseline-to-follow-up change is intended to describe how that indicator moves during the study period.
A change endpoint requires measurements at the relevant time points. The registry states that the study was terminated early, no laboratory tests were performed, and no outcome data were collected. Consequently, there is no reported baseline value, Week 18 value, or change estimate to interpret. The record also does not report the unit or statistical summary planned for the endpoint.
The study’s description includes safety and tolerability as objectives, but the listed primary endpoint is HbA1c. The registry provides no analyzed primary outcome and no laboratory results. The endpoint’s intended role can therefore be described, but its observed effect and precision cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical finding is that the planned primary outcome was not observed or analyzed. The registry states that the study ended early, no laboratory tests were performed, and no outcome data were collected. It lists one outcome measure and no analyses. Accordingly, there is no reported estimate of change in HbA1c from baseline to Week 18, and no confidence interval or other measure of precision is available.
This is not a result showing no change. A finding of no change would require measured values and an analysis capable of estimating change. Here, the data needed for that estimate were not collected. The same distinction applies to safety: zero counts in an adverse-event grouping with zero participants at risk do not establish that no adverse events occurred. They indicate that the registry record does not provide an analyzed safety experience for that grouping.
The registry lists an enrollment value of 10, but enrollment is not an outcome analysis. It should not be read as evidence that outcome measurements were obtained from those participants, nor as a basis for estimating treatment effect or precision. The record specifically says that no data were analyzed for the primary outcome. The number of participants with usable endpoint measurements is therefore not reported in the registry record.
The design also limits what could have been inferred even if measurements had been available. A single-group study without randomization or a separate comparator can describe change over time in that group, but it cannot isolate the effect of treatment from other explanations for a change. In this study, the more immediate limitation is that the planned outcome was not measured at all. Neither a within-group change nor a controlled treatment contrast can be estimated from the posted results.
There is therefore no basis in the registry record for concluding that sitagliptin did or did not change HbA1c in this study, or for drawing a safety conclusion. The outcome’s direction, magnitude, and precision are unavailable. This interpretation concerns the information recorded for this terminated study, not a general claim about the treatment.
9. Statistical Methods Explained
The registry describes a single-group, nonrandomized, open-label study with no masking. Those design labels matter because they determine what kind of statistical comparison the data could support. With one group, the planned baseline-to-Week 18 endpoint would ordinarily be a within-group change. A randomized comparison would instead assess how outcomes differ between assigned groups. The registry records no comparator group, so an effect relative to placebo or another treatment was not part of this design.
What would a change estimate describe?
In general, a change estimate summarizes the difference between measurements taken at baseline and follow-up for the people with relevant measurements. Statistical methods can summarize that change as an average or another selected measure, and can quantify uncertainty around it. A confidence interval expresses a range of values compatible with the data and the method used; it helps show how precisely an effect has been estimated. Such summaries require observed measurements. The registry says no laboratory tests were performed and no outcome data were collected, so no change estimate or interval can be calculated from the posted outcome record.
Even when a before-and-after change is measurable, it is not equivalent to a randomized treatment contrast. General influences over time, changes in care, measurement variability, and participant characteristics may contribute to observed changes in a single group. A comparator and random allocation can help address some of these issues in a controlled design. They are absent here, and no measured change is available to describe in the first place.
What can the record say about analysis?
The registry lists no analyses for the outcome. It does not report a statistical model, a method for summarizing change, an adjustment strategy, or a rule for handling repeated or incomplete measurements. Those details are not reported in the registry record. They should not be inferred from the endpoint title or from the general study description.
In general, the choice of summary and model depends on the outcome, the measurement schedule, and the analysis question. Variability among participants affects how precisely a group estimate can be made. If observations are more variable than a simple model assumes, methods that account for over-dispersion may be relevant in appropriate settings. But the registry provides no outcome values or dispersion measure here, and it reports no selected model. These concepts explain why analysis choices matter; they do not supply an analysis for this study.
How should planning illustrations be read?
Any sample-size illustration based on an observed effect is a planning calculation, not a measure of power observed in the completed study. The registry describes an illustration using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a chosen fraction of an observed effect; it also distinguishes participant-per-arm calculations from total-event calculations for time-to-event outcomes. These are assumptions for hypothetical planning, not characteristics of this single-group, nonrandomized trial.
Because the primary outcome was not collected, the study has no observed HbA1c effect on which to base an effect-dependent planning illustration. Such an illustration cannot be interpreted as evidence about the study’s treatment effect, precision, or observed power. A sample-size justification or a trial-specific statistical design calculation is not reported in the registry record.
Finally, statistical significance testing cannot repair the absence of measurements. A p-value would require an estimate and its uncertainty under a specified analysis. Neither is reported. The appropriate statistical description is therefore that the planned endpoint is unavailable, rather than that it was tested and found statistically significant or nonsignificant.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure: change from baseline in HbA1c at Week 18. It reports no analyses for that outcome and states that no outcome data were collected. With no analyzed endpoint, there are no reported p-values or estimates whose interpretation would depend on adjustment for multiple comparisons. A multiplicity strategy is not reported in the registry record, so it is not possible to determine whether any planned secondary, subgroup, or repeated-measure analyses were to be adjusted.
The primary endpoint is not simply an outcome with an unreported value. The registry says the study ended early and no laboratory tests were performed. Thus, there are no recorded outcome measurements to include in an analysis or to recover through a reported missing-data method. Imputation, sensitivity analyses, and other procedures for handling missing measurements are not reported in the registry record.
The record says no data were analyzed for the primary outcome. It does not describe an analysis population, such as a population defined by treatment received or by availability of measurements. Although enrollment is listed as 10, that value does not identify who had an endpoint measurement or who entered an analysis.
Safety information also requires caution: the adverse-event grouping lists zero participants at risk and zero reported event counts. Those entries do not provide an analyzed safety population or establish that no events occurred. The registry record does not report further details on safety ascertainment or missing safety data.
11. What the Result Does, and Does Not, Mean
The record documents a planned study question, not an observed HbA1c result. The intended endpoint was change from baseline at Week 18, but the registry says no laboratory tests were performed and no outcome data were collected. It follows that there is no treatment-effect estimate, direction of change, or measure of statistical precision to interpret.
This absence of data should not be converted into a claim that HbA1c did not change. It also should not be treated as evidence that sitagliptin improved the measure. Both claims would require observations that are not present in the record. The same principle applies to safety: zero counts paired with zero participants at risk do not show that the treatment caused no adverse events.
The study was single-group, nonrandomized, and open-label, with no comparator. In general, this design can describe outcomes within the group if those outcomes are measured, but it cannot provide the same treatment contrast as a randomized controlled comparison. Here, the registry reports neither a within-group endpoint result nor a controlled contrast. No conclusion about comparative effectiveness or safety follows from these posted results.
The registry lists enrollment as 10, but that listing does not substitute for an outcome analysis and should not be interpreted as the number with measured or analyzed HbA1c. The reason for early termination, the statistical plan, and the handling of missing data are not reported in the registry record. The defensible interpretation is limited: the planned outcome could not be evaluated from the data recorded for this study.
12. Why This Trial Matters Statistically
This study illustrates a basic distinction in clinical-trial interpretation: a trial’s planned question and its observed result are not the same thing. The registry specifies a population, a sitagliptin intervention, and a planned HbA1c endpoint, but it also records early termination and no outcome data. A clear endpoint definition cannot produce an effect estimate when the relevant measurements were never obtained.
It also demonstrates why enrollment figures and outcome analyses must be interpreted separately. The record lists enrollment as 10, while stating that no data were analyzed for the primary outcome. Enrollment alone does not establish that participants contributed endpoint measurements, nor does it show how precise an estimate would have been.
The design provides a further statistical lesson. A single-group study can address a within-group description if measurements are available, but it has no randomized comparator for estimating a treatment contrast. In this record, neither type of outcome estimate is available. Statistical analysis cannot compensate for missing outcome collection, and a planning calculation cannot be treated as a result.
For biostatisticians and clinical researchers, the record is a reminder to separate what was intended, what was measured, and what was analyzed. Here, the registry supports description of the planned question and the reasons the endpoint cannot be interpreted, but it does not support an efficacy or safety estimate.
13. 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 direct limitation is that the study was terminated early and the registry states that no laboratory tests were performed and no outcome data were collected. The planned HbA1c endpoint therefore has no reported measurement, estimate, or precision interval. No data were analyzed for that outcome.
The design was nonrandomized, open-label, and single-group, with no comparator. Even if within-group measurements had been available, this design would not have posted a randomized comparison against another treatment or placebo. The absence of outcome data prevents even a descriptive estimate of the intended baseline-to-Week 18 change.
The registry lists enrollment as 10, but does not report how many participants completed the study, had measurements, or belonged to an analysis population. It also does not report the reason for termination, a sample-size justification, a detailed statistical analysis plan, or a method for handling missing data. Those omissions limit assessment of the intended analysis and the circumstances around the unavailable endpoint.
For safety, the adverse-event grouping lists zero participants at risk and zero event counts. These entries do not provide an evaluable safety population and cannot support an inference that events did not occur. Further safety-collection details are not reported in the registry record.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: The Effect of Sitagliptin in Type 2 Diabetes Mellitus With Inadequate Glycemic Control (MK0431-118) — NCT00832624.
- Registry record last updated 2017-05-23; status last verified 2017-04.
- Results first posted 2010-10-11.
- 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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17. Record Summary
The registry describes a Phase 4, open-label, nonrandomized, non-placebo-controlled, single-group study of sitagliptin in adults with type 2 diabetes and inadequate glycemic control. The planned primary endpoint was change from baseline in HbA1c at Week 18. The record lists enrollment as 10, a start date of 2008-11-26, and a primary completion date of 2009-09-02; the study status is terminated.
The registry states that the study ended early, no laboratory tests were performed, and no outcome data were collected. It lists one outcome measure and no analyses. Consequently, there is no reported HbA1c effect estimate or analyzed safety result. The reason for termination and further statistical methods are not reported in the registry record.