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 Study to Assess the Efficacy and Safety of Sitagliptin in Recently Diagnosed, Naive Type 2 Diabetics With Inadequate Glycemic Control on Diet and Exercise (0431-158) (NCT00832390), a randomized phase 4 study. The primary outcome is Change From Baseline in A1C at Week 24.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00832390 |
| Phase | Phase 4 |
| Condition | Diabetes Mellitus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 29 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
The study title describes people with recently diagnosed type 2 diabetes who were treatment-naive and had inadequate glycemic control on diet and exercise. The primary outcome’s population field is blank, so the registry record does not report further details about the population included in that analysis.
Intervention
The listed regimens include sitagliptin 100 mg once daily, and sitagliptin 100 mg once daily with metformin. The registry record identifies sitagliptin phosphate as the drug intervention but does not provide further details about the metformin regimen.
Comparator
The comparator is a standard care regimen. Its outcome entry is reported for 1 participant. That very small comparator group limits what can be learned from an across-group contrast, and the registry record does not post a two-arm comparison analysis.
Primary question
The primary question concerns the mean change in A1C from baseline to week 24 for each listed regimen. A1C is reported as a percent value, while the endpoint is the difference between the week 24 value and the baseline value. The record posts arm-level means and confidence intervals, but no estimated contrast between regimens.
3. Trial Design
The registry record describes a randomized, parallel-group phase 4 trial with no masking. The study status is completed. Its title concerns sitagliptin in recently diagnosed, treatment-naive people with type 2 diabetes whose glycemic control was inadequate on diet and exercise. The brief summary says efficacy and safety were to be evaluated after 24 weeks of treatment.
The record lists three regimens: sitagliptin 100 mg once daily, sitagliptin 100 mg once daily with metformin, and standard care. The outcome entries list 12 participants for sitagliptin alone, 16 for sitagliptin with metformin, and 1 for standard care. The record gives total enrollment as 29, but does not explain the relationship between that figure and the outcome-specific group counts.
The study began on 2007-02-14, and primary completion was recorded as 2008-07-11. The sponsor is Merck Sharp & Dohme LLC. The allocation is identified as randomized, but the randomization procedure, sequence generation, concealment, and any stratification are not reported in the registry record. Masking is listed as none; the record does not describe whether any outcome assessment procedures differed across groups.
The listed endpoint is continuous: mean change in A1C from baseline to week 24, with a 95% confidence interval. The registry record does not report a statistical analysis plan, an analysis population, or a direct comparison between regimens. The posted results therefore describe group-level outcomes rather than a documented treatment-effect estimate.
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: Treatment naïve patients (30 to 78 years of age) with inadequate glycemic control on diet/exercise were assigned to treatment with sitagliptin alone (A1C 6.5 to \<8%), sitagliptin + metformin as initial combination therapy (A1C 8-12%), or standard care.
Overall Study
| Stage | Sitagliptin 100 mg q.d. (Once Daily) | Sitagliptin 100 mg q.d. (Once Daily) and Metformin | Standard Care Regimen |
|---|---|---|---|
| STARTED | 12 | 16 | 1 |
| COMPLETED | 12 | 16 | 1 |
| NOT COMPLETED | 0 | 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 | Sitagliptin 100 mg q.d. (Once Daily) | Sitagliptin 100 mg q.d. (Once Daily) and Metformin | Standard Care Regimen | Total |
|---|---|---|---|---|---|
| Participants analysed | 12 | 16 | 1 | 29 | |
| Age, Continuous | years | 57.6 (SD 14.1) | 52.5 (SD 9.3) | 51.0 (SD 0.0) | 54.62 (SD 11.43) |
| Sex: Female, Male: Female | Participants | 6 | 13 | 1 | 20 |
| Sex: Female, Male: Male | Participants | 6 | 3 | 0 | 9 |
| Body Mass Index (BMI) | kg/m2 | 27.4 (SD 10.0) | 28.9 (SD 5.2) | 26.0 (SD 0.0) | 28.14 (SD 7.41) |
| Glycosylated Hemoglobin A1C (A1C) | Percent | 7.1 (SD 0.6) | 8.6 (SD 1.4) | 6.9 (SD 0.0) | 7.96 (SD 1.33) |
| Time Since Diagnosis of Diabetes | Years | 5.3 (SD 7.0) | 6.2 (SD 6.0) | 5.2 (SD 0.0) | 5.82 (SD 6.25) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in A1C at Week 24, measured over Baseline and 24 Weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Percent Difference |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in A1C at week 24, defined as the week 24 A1C value minus the baseline, or week 0, value. A1C is recorded as a percent; the change is a difference between percent values. The record reports the mean change and a 95% confidence interval for each listed regimen.
A1C is used as a measure of glycemic control over time. As a continuous endpoint, it can describe the average direction and size of change within a group while retaining more information than a simple category such as improved or not improved. That general advantage does not itself establish that a difference between groups is reliable or attributable to a regimen. Such a claim requires an appropriate comparative analysis and information about its uncertainty.
The primary endpoint’s timeframe is baseline and 24 weeks. The registry record does not report further details about how A1C was measured, how missing measurements were handled, or which participants were included in the endpoint analysis. Those omissions limit interpretation of the posted arm-level summaries.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For sitagliptin 100 mg once daily, the posted mean change in A1C was -0.2, with a 95% confidence interval from -0.9 to 0.5. For sitagliptin 100 mg once daily with metformin, the mean change was -1.0, with a 95% confidence interval from -2.1 to -0.1. For standard care, the mean change was 0.0, with a 95% confidence interval from 0.0 to 0.0. The record lists 12 participants, 16 participants, and 1 participant, respectively, for these outcome entries.
These figures are arm-level summaries. They describe the posted average changes and their reported intervals; they are not a direct estimate of the difference between any two regimens. The registry record does not post a comparative analysis or a p-value for the primary endpoint. It also does not describe the method used to form the confidence intervals, so their calculation cannot be assessed from the record alone.
In general, a confidence interval expresses uncertainty around an estimated quantity under the method used to calculate it. It should not be read as a range containing the outcomes of all individuals, nor as a guarantee about the result of a future study. A confidence interval for a group mean also does not, by itself, answer whether the group’s result differs from another group’s result. A direct contrast and its uncertainty are needed for that question.
The standard-care result is reported with a confidence interval from 0.0 to 0.0 and an outcome count of 1. The registry record does not explain how that interval was generated. It should therefore be reported as recorded, without treating its displayed width as evidence of precision or drawing conclusions about comparative uncertainty from it.
The endpoint entries alone do not establish why the group means differ. The record does not give baseline A1C summaries, adjustment methods, or details about adherence and co-interventions. It also does not describe the analysis population or missing-data handling. These omissions matter because arm-level changes can be affected by the characteristics of the participants included and by the way incomplete observations are treated.
The posted estimates are descriptive evidence about the recorded outcomes. They do not support a claim that one regimen is superior, equivalent, or different from another. In particular, the small standard-care outcome group and the absence of a posted two-arm analysis make a formal comparative interpretation unavailable from this registry record.
9. Statistical Methods Explained
The primary outcome is continuous, and the record reports a mean for each regimen. A mean describes the arithmetic average of the observed endpoint values in the analysis group. In this case, the outcome is the change in A1C between baseline and week 24. A negative mean represents a negative average change as defined by the endpoint; it does not describe every participant’s change.
The reported uncertainty measure is a 95% confidence interval. In general, a confidence interval is calculated using an estimate and an assumed sampling model. It communicates how compatible a range of values is with the observed data under that model and procedure. It is not a statement that a specified share of individual participants had results inside the interval. The registry record does not identify the calculation method, assumptions, or whether any adjustment was applied, so the displayed intervals cannot be independently evaluated from the record.
For sitagliptin alone, the recorded mean is -0.2 and the confidence interval is -0.9 to 0.5. For sitagliptin with metformin, the mean is -1.0 and the interval is -2.1 to -0.1. For standard care, the mean is 0.0 and the interval is 0.0 to 0.0. These are separate summaries for the listed regimens. They are not contrasts, and one should not infer a treatment comparison merely by inspecting whether intervals overlap or exclude a particular value. A comparative analysis would need to estimate a difference between groups, with uncertainty calculated for that difference.
The registry record identifies the allocation as randomized and the design as parallel, but does not report the allocation sequence, concealment, or analysis procedures. Random allocation is generally intended to reduce systematic differences between groups at the start of a trial. Whether that goal was achieved cannot be judged from the allocation label alone; assessment would require procedural and baseline information not reported in the registry record. The record also lists no masking, which means the design is unmasked, but it does not describe who knew the assigned regimen or how that knowledge was managed during measurement and analysis.
The record gives an outcome count for each regimen, including 1 for standard care. The enrollment field reports 29. These entries should not be treated as interchangeable: the record does not explain which participants contributed to the endpoint or why the outcome counts take the displayed values. The analysis populations, participant flow, withdrawals, and numbers with missing endpoint measurements are not reported in the registry record.
A separate planning illustration is described in the record as based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration is described as considering an effect that is a stated fraction of the observed effect. The registry record does not report an actual sample-size justification for this trial. Any planning values are illustrations for future planning, not evidence about the probability that this completed trial detected an effect. They are not observed power.
Over-dispersion is a general concern when observed variability is greater than assumed by a statistical model. For a continuous outcome, an incorrect variability assumption can make standard errors and confidence intervals too small or too large. The registry record does not report a dispersion estimate or a model-based analysis, so it does not establish whether over-dispersion was assessed or relevant to the posted summaries.
The record indicates that a two-arm comparison for the continuous endpoint could not be estimated. No recalculated comparative estimate is available, and the registry record lists no posted analyses. Consequently, the posted means and intervals should be interpreted as descriptive arm-level results. They do not replace a sponsor analysis or an explicitly reported comparative model, neither of which is presented for this endpoint in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one primary outcome measure and no posted secondary outcome results. It does not report a multiplicity-control plan, such as a prespecified approach to interpreting several outcomes or comparisons together. Without that information, it is not possible to determine whether multiplicity was considered in the trial’s statistical plan. No p-values or direct comparisons for the primary outcome are posted.
Missing-data methods are not reported in the registry record. The record does not state how many participants had an A1C measurement at baseline or week 24, whether any endpoint values were missing, or how incomplete observations were handled. It also does not describe withdrawals, exclusions, imputation, or sensitivity analyses. The outcome counts are reported by regimen, but the record does not explain how those counts relate to enrollment or to the analysis population.
The analysis population is not reported in the registry record. It is therefore unclear whether the outcome summaries include everyone assigned to a regimen, only those who completed treatment, or another defined group. The record does not describe whether participants were analyzed according to their randomized assignment or whether any participants were excluded after randomization.
These are not minor technical details: the choice of population and missing-data approach can affect the meaning of a mean change and the uncertainty around it. The posted results can be described as recorded, but the registry record does not supply enough information to assess the effect of missing observations, departures from assignment, or multiple testing on the interpretation.
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 100 mg q.d. (Once Daily) | 0 | 12 | 0.0% |
| Sitagliptin 100 mg q.d. (Once Daily) and Metformin | 0 | 16 | 0.0% |
| Standard Care Regimen | 0 | 1 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Sitagliptin 100 mg q.d. (Once Daily) | 1 of 12 |
| Sitagliptin 100 mg q.d. (Once Daily) and Metformin | 0 of 16 |
| Standard Care Regimen | 0 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Sitagliptin 100 mg q.d. (Once Daily) | Sitagliptin 100 mg q.d. (Once Daily) and Metformin | Standard Care Regimen |
|---|---|---|---|---|
| Hypertension | Vascular disorders | 1 of 12 | 0 of 16 | 0 of 1 |
The posted serious-adverse-event entries report 0 events among 12 participants at risk for sitagliptin 100 mg once daily, 0 among 16 at risk for sitagliptin 100 mg once daily with metformin, and 0 among 1 at risk for standard care. These are the recorded counts; the registry record does not provide further detail about the events monitored or the period of safety follow-up.
The absence of reported serious adverse events in these entries is not evidence that serious events could not occur. Safety findings depend on the participants observed, the length and completeness of follow-up, and how events were collected and classified. The record does not give enough information to assess those features or to compare safety between regimens.
For other adverse events, the registry record lists 1 event among 12 participants at risk in the sitagliptin-alone group, 0 among 16 in the sitagliptin-with-metformin group, and 0 among 1 in the standard-care group. Death counts are not reported in the registry record. These counts should be read separately from the serious-adverse-event entries and should not be interpreted as a complete account of safety without further definitions and follow-up information.
12. What the Result Does, and Does Not, Mean
The registry record documents mean A1C changes at week 24 for sitagliptin alone, sitagliptin with metformin, and standard care. The posted values are -0.2, -1.0, and 0.0, respectively, each accompanied by a 95% confidence interval. They offer a description of the recorded group-level outcomes, not a direct estimate of how much one regimen differs from another.
The outcome counts are 12 for sitagliptin alone, 16 for sitagliptin with metformin, and 1 for standard care. The comparator count is particularly limited for interpreting an across-group contrast. The registry record does not post a two-arm comparison analysis, a p-value, or a comparative confidence interval. Accordingly, the arm-level summaries should not be used to claim superiority, equivalence, or absence of a difference.
Nor do the entries establish that the regimens caused the reported changes. The allocation is listed as randomized, but the record does not provide details about the randomization process, baseline characteristics, analysis population, missing data, or adjustment methods. Those details are relevant to evaluating whether a comparative conclusion is supported.
The posted safety counts are also limited: no serious adverse events are listed in any regimen, while other adverse events are recorded in the sitagliptin-alone group. The record does not provide enough information about ascertainment, follow-up, or event definitions to treat these entries as a complete characterization of safety.
The appropriate conclusion is narrow. The record reports arm-level endpoint and adverse-event summaries for a completed, randomized, unmasked phase 4 study. It does not provide the statistical and clinical detail needed for a firm comparative assessment, and it does not establish how the findings apply beyond the recorded study population.
13. Why This Trial Matters Statistically
This trial illustrates the distinction between reporting outcomes within groups and estimating a treatment contrast. A mean change for each regimen can describe the observed endpoint, but a question about whether regimens differ calls for an explicit comparison. The registry record does not post such an analysis for the primary outcome, so the arm-level means cannot substitute for one.
The standard-care outcome count is 1. That makes the comparator summary difficult to use as a basis for a stable comparison, regardless of how the displayed mean and interval appear. The record’s confidence interval for standard care is 0.0 to 0.0, but does not describe how that interval was calculated. This is a reminder that statistical output should be interpreted alongside the method and the amount of information behind it.
The record also shows why trial registration and outcome reporting need to be read together with design and analysis details. The study is identified as randomized and parallel, but the record does not document the randomization procedure, analysis population, missing-data approach, or multiplicity plan. Without those details, readers can describe the posted figures but cannot fully evaluate the analysis that produced them.
Finally, the safety entries are counts rather than a complete account of safety evidence. The absence of recorded serious adverse events in the listed groups does not answer questions about the thoroughness or duration of surveillance. The statistical lesson is to distinguish a reported count from a comparative risk estimate and to avoid conclusions that exceed the information documented in the registry record.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record does not report a direct comparison for the primary endpoint. The available outcomes are group-level means and confidence intervals, and the record identifies the continuous-endpoint two-arm comparison as unavailable. Therefore, the results do not establish a comparative effect between any pair of regimens.
The standard-care outcome entry includes 1 participant, while the other listed outcome entries include 12 and 16. This imbalance, especially the very small comparator group, limits interpretation of the standard-care summary as a basis for comparison. The record does not explain why these outcome counts differ from the total enrollment entry or whether all randomized participants contributed endpoint data.
The population field for the primary outcome is blank. Although the study title describes recently diagnosed, treatment-naive people with type 2 diabetes and inadequate control on diet and exercise, the registry record does not report detailed eligibility criteria or characteristics of the participants included in the analysis. Baseline A1C values and other baseline summaries are not reported.
The record does not describe how the confidence intervals were calculated, how missing endpoint values were handled, or which analysis population was used. It also does not report the randomization procedure, a multiplicity plan, or a statistical analysis plan. The safety entries lack further detail on event definitions and follow-up, and death counts are not reported in the registry record.
These gaps limit independent assessment of precision, bias, and applicability. They do not justify filling in unreported methods or treating the posted arm-level results as a complete comparative analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study to Assess the Efficacy and Safety of Sitagliptin in Recently Diagnosed, Naive Type 2 Diabetics With Inadequate Glycemic Control on Diet and Exercise (0431-158) — NCT00832390.
- Registry record last updated 2017-05-30; status last verified 2017-04.
- Results first posted 2009-07-31.
- 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
This completed phase 4 study is listed as randomized, parallel, and unmasked. Its title concerns sitagliptin in recently diagnosed, treatment-naive people with type 2 diabetes and inadequate glycemic control on diet and exercise. The study began on 2007-02-14, and primary completion was recorded as 2008-07-11.
The primary endpoint is mean change in A1C from baseline to week 24, reported with 95% confidence intervals. The registry record posts outcome summaries for sitagliptin alone, sitagliptin with metformin, and standard care, but no direct two-arm comparison analysis. Its safety entries report no serious adverse events in the listed groups; death counts are not reported.
Key analysis details—including missing-data handling, analysis populations, and the confidence-interval method—are not reported in the registry record. The posted results therefore support a descriptive reading of the recorded outcomes, not a firm comparative conclusion.