PMS of Trazenta on the Long-term Use as Add-on Therapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PMS of Trazenta on the Long-term Use as Add-on Therapy (NCT01904383), a registered phase not stated study. The primary outcome is Percentage of Participants With Drug Related Adverse Events.

2. Clinical Question

3. Trial Design

This record describes a completed post-marketing surveillance study of Trazenta tablets as add-on therapy in patients with type 2 diabetes mellitus. The listed study title is “PMS of Trazenta on the Long-term Use as Add-on Therapy.” Its stated purpose was to investigate the safety and efficacy of long-term daily use. Boehringer Ingelheim is listed as the sponsor. The recorded study start date is 2013-07-01, and the primary completion date is 2018-10-04. The study status is completed.

The registry lists an enrollment of 4057 and one drug intervention, Trazenta. It does not describe a comparator or specify allocation. In particular, there is no basis in the record for interpreting this as a randomized controlled comparison. The record explicitly cautions that the arms are not a like-for-like control comparison. The listed safety set includes patients dispensed Trazenta as add-on therapy who had at least one observation after treatment; patients treated with Trazenta as monotherapy were excluded from that set.

The primary outcome is the percentage of participants with drug-related adverse events over a treatment period extending from first to last drug administration, up to approximately 156 weeks. A secondary outcome is the mean change from baseline to the last observation of the treatment period in haemoglobin A1c (HbA1c). Although the record lists two outcome measures, it does not provide numerical results for the primary endpoint or the HbA1c outcome in the information reported. It also lists no statistical analyses. The duration and observational nature of the record are important context: the posted findings describe events observed among treated patients, not an estimate from a stated randomized contrast.

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: This non-randomized, post marketing surveillance (PMS) was a prospective study using a continuous investigation system. No specific criteria (e.g., demographics, baseline characteristics, concomitant drugs in use) were defined for participant enrolment. Participants were enrolled from July 2013 to September 2015.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety set: This patient set included all patients who were dispensed Trazenta® Tablets as add-on therapy, and had at least 1 observation after treatment. The patients treated with Trazenta® Tablets as monotherapy were not included.

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: Safety set: This patient set included all patients who were dispensed Trazenta® Tablets as add-on therapy, and had at least 1 observation after treatment. The patients treated with Trazenta® Tablets as monotherapy were not included.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With Drug Related Adverse Events, measured over From first drug administration until last drug administration, up to approximately 156 weeks..

The primary endpoint is the percentage of participants with drug-related adverse events. Its stated observation window runs from first drug administration until last drug administration, up to approximately 156 weeks. The specified population is the safety set: patients dispensed Trazenta as add-on therapy who had at least one observation after treatment. Patients treated with Trazenta as monotherapy were not included in this population.

Expressing an event outcome as a percentage is a way to describe how often participants in a defined population experienced the event during a specified period. It does not, by itself, describe how severe each event was, how long it lasted, or whether it occurred once or repeatedly. Nor does it establish that treatment caused an event; the registry's endpoint specifically refers to events judged to be drug-related, but the numerical result and the details of that assessment are not reported in the registry record.

This endpoint is relevant to a post-marketing safety investigation because it focuses on adverse events during ongoing use in the stated treatment setting. However, the record does not report the endpoint's percentage, the event count used to derive it, or a confidence interval. The serious and other adverse-event figures reported separately should not be substituted for this primary measure: the registry does not state that those figures represent the drug-related adverse events used for the primary endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary measure as a participant percentage and gives its observation period and safety population. These definitions matter because an event percentage has meaning only in relation to who was counted and over what period. In general, a percentage describes the proportion of a defined population meeting an event criterion. It is not a rate per unit of time unless the measure is explicitly defined that way. Here, the stated endpoint is a percentage of participants, not a person-time rate.

What does the endpoint’s time window mean?

The stated window begins with first drug administration and ends with last drug administration, up to approximately 156 weeks. This describes when the endpoint events were to be observed; it does not imply that every participant was followed for the same length of time. The actual participant-level treatment durations and follow-up completeness are not reported in the registry record. In general, when observation durations differ, a simple percentage may not convey the same information as a time-to-event analysis or an incidence rate. The record does not report either type of adjusted time-based analysis for this endpoint.

How should the safety population be understood?

The safety set is defined as patients dispensed Trazenta as add-on therapy with at least one observation after treatment. Patients who received Trazenta as monotherapy were excluded. This is a population definition, not a description of random allocation. Since the criteria require an observation after treatment, the set may differ from the enrolled population, but the record does not explain how each patient entered or left the analysis population. The enrollment figure of 4057 and the adverse-event at-risk count of 3372 should therefore be read as separately reported figures, not reconciled by assuming an unreported participant flow.

What can counts and percentages tell us?

Counts show how many participants were recorded as affected within the reported group. A percentage can make an event frequency easier to interpret relative to its stated denominator. Neither alone describes the precision of an estimate. In general, a confidence interval expresses the range of values compatible with the observed data under a specified statistical model and sampling assumptions. No confidence interval is reported for the primary endpoint or for the adverse-event counts in the registry information available. Statistical significance cannot be assessed without a stated analysis and its results; moreover, significance is not a substitute for judging the size and uncertainty of an effect.

The adverse-event entries separate serious events from other events, and list participants at risk and affected for each category. Those categories are not interchangeable with the primary endpoint, which concerns drug-related adverse events. The record does not say that the serious and other event counts are restricted to events judged drug-related. Nor does it provide a cross-tabulation showing overlap between categories. It would therefore be inappropriate to combine the counts, infer a unique number of affected participants, or treat them as the numerator for the primary endpoint.

Why is a comparator important?

In general, a controlled comparison can help distinguish an intervention effect from differences in patient characteristics, background care, observation, or the underlying course of a condition. Here, the registry does not state allocation and cautions that the arms are not a like-for-like control comparison. The listed findings are consequently best read descriptively. They do not estimate a randomized treatment contrast, and the record does not report an adjusted comparative analysis that could address differences between groups.

What do the planning assumptions mean?

The record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that the target effect is a stated fraction of the observed effect. In general, such calculations illustrate how a hypothetical future study might be planned under assumed conditions; they are not observed results, and they are not the power achieved by this surveillance study. The record does not report a trial-specific design justification or a sample-size rationale. No planning quantity should be interpreted as a result of the surveillance study.

More generally, a normal approximation is a modeling choice that can be useful for some planning calculations, but its suitability depends on the outcome and assumptions. Event counts may be sparse for particular event types, and repeated or clustered events can require methods that account for more than a simple participant-level proportion. Over-dispersion, in general, means that variability exceeds what a chosen model expects; accounting for it can widen uncertainty or change standard errors. The registry does not report that such a model was used, nor does it describe a model for recurrent events, adjustment variables, or subgroup estimation.

The record lists two outcome measures and zero analyses. It does not provide analysis methods for the primary endpoint, the HbA1c outcome, or adverse events. Consequently, the statistical interpretation is constrained to the definitions and descriptive counts that are actually stated. Details such as confidence intervals, missing-data handling, and any adjustment for multiple outcomes are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: the primary percentage of participants with drug-related adverse events and a secondary measure of mean change in HbA1c from baseline to the last observation of the treatment period. It also lists zero analyses. No statistical analysis plan, testing hierarchy, or adjustment for multiple outcomes is reported in the registry record. In general, assessing several outcomes can increase the chance of a misleading positive finding if each is tested separately without an appropriate plan. That general concern cannot be resolved for this study because the record does not report inferential results or a multiplicity strategy.

The primary endpoint result and the HbA1c result are not reported numerically. The record does not state how missing outcome observations were handled, whether participants with incomplete follow-up were excluded from a particular analysis, or whether any imputation method was used. It defines the safety set as patients dispensed Trazenta as add-on therapy with at least one observation after treatment, but that definition alone does not describe missing-data procedures or the analysis population for every outcome.

The enrollment figure is 4057, while the serious- and other-event entries each list 3372 participants at risk. The record does not provide a participant-flow account or explain the difference between these figures. They should not be used to infer missingness or attrition mechanisms. In general, missing data can affect an estimate when the probability of having an observed outcome is related to the outcome itself or to participant characteristics. Whether that occurred is not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumonia bacterial (0.4%), cardiac failure (0.4%), diabetic nephropathy (0.3%), gastric cancer (0.2%), hypoglycaemia (0.2%).

The adverse-event information lists 3372 participants at risk for serious adverse events, of whom 304 were affected. It separately lists 3372 at risk for other adverse events, with 184 affected. These are descriptive counts, not estimates of a comparison between Trazenta and a control treatment. The record also lists 74 deaths. It does not report that these deaths were attributed to treatment, or explain their relationship to the serious-event count.

The serious-event terms with the largest listed percentages include Pneumonia bacterial at 0.4%, Cardiac failure at 0.4%, Diabetic nephropathy at 0.3%, Gastric cancer at 0.2%, Hypoglycaemia at 0.2%, and Cerebral infarction at 0.2%. These are registry-listed event terms and percentages; they do not establish causation. The record does not say whether participants could contribute more than one event term, so the percentages should not be added or treated as mutually exclusive categories.

Serious events, other events, deaths, and drug-related adverse events are distinct descriptions in the record. The primary endpoint concerns drug-related events, but the serious and other event counts are not identified as its components. Because no primary endpoint percentage or uncertainty interval is reported, the event counts cannot replace that missing result or show how precisely the primary safety outcome was estimated.

12. What the Result Does, and Does Not, Mean

The posted information establishes that this was a completed post-marketing surveillance study of Trazenta as add-on therapy in patients with type 2 diabetes mellitus. It documents the stated safety population, an observation period extending from first to last drug administration up to approximately 156 weeks, and adverse-event counts for the Trazenta group. The record also identifies HbA1c change as a secondary outcome. These details describe the study’s scope and the findings that are available in the registry.

The record does not provide the numerical result for the primary endpoint, which is the percentage of participants with drug-related adverse events. It also does not report the HbA1c outcome result, confidence intervals, or analyses. Thus, the posted data do not quantify the primary endpoint's frequency or precision. The serious and other adverse-event counts are not a substitute for that endpoint because their relationship to drug-related events is not specified.

In general, observing an event during treatment does not by itself show that treatment caused it. A causal conclusion requires a design and analysis that support comparison with an appropriate counterfactual, together with adequate control of bias and uncertainty. Here, allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. The reported counts therefore should not be interpreted as evidence that Trazenta caused or prevented the listed events.

Nor does the record support a conclusion about efficacy: although the study summary says it investigated efficacy and the secondary outcome concerns HbA1c, no numerical result is reported. The appropriate reading is limited to the registry’s descriptive information. Absence of a reported endpoint or analysis is not evidence of no effect, no risk, or no events; it means that the corresponding statistical conclusion cannot be drawn from the record.

13. Why This Trial Matters Statistically

This study illustrates a central issue in post-marketing safety interpretation: a long observation window and a defined treated population can produce useful descriptive information, but event counts alone do not establish a treatment effect. The registry describes long-term daily use as the subject of surveillance and specifies a period from first to last administration, up to approximately 156 weeks. This makes clear that the safety question concerns events recorded during treatment rather than a short, fixed assessment point.

The record also shows why endpoint definitions and analysis populations must be kept distinct. Its primary endpoint is the percentage of participants with drug-related adverse events in a defined safety set. Separately reported serious and other adverse-event counts describe categories that are not explicitly identified as the primary endpoint’s events. Treating these measures as equivalent would change the question being answered.

Statistically, the absence of a stated comparator is consequential. A descriptive frequency can characterize events among treated participants, but without a suitable comparison it cannot isolate treatment-associated risk from other explanations. The registry explicitly warns that the arms are not a like-for-like control comparison and does not state allocation. The missing primary result and lack of listed analyses further limit assessment of precision and inference.

The record is therefore useful as an example of why surveillance findings should be read alongside their population, time window, event definitions, comparator structure, and reporting completeness. It also demonstrates that an enrollment figure does not automatically identify the denominator for every endpoint. A transparent participant flow and endpoint-specific results would be needed to interpret how the reported counts relate to the primary question; those details are not reported 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 the numerical result for the primary endpoint or the secondary HbA1c outcome. It lists no analyses, so statistical methods, effect estimates, and uncertainty intervals cannot be evaluated from the record. This leaves the central safety question unquantified and prevents assessment of the precision of any endpoint estimate.

The study has no stated comparator or allocation method. The record cautions that arms are not a like-for-like control comparison. Consequently, the reported adverse-event counts are descriptive and cannot support a direct causal comparison. The record also does not describe treatment dose, background therapies, eligibility criteria beyond the stated safety-set definition, or participant characteristics that might help assess how applicable the findings are to other populations.

The enrollment figure is 4057, whereas the adverse-event entries report 3372 participants at risk. The registry does not explain this difference through participant flow or endpoint-specific exclusions. It also does not report follow-up completeness, missing-data procedures, event adjudication details, or how drug relationship was determined. The serious and other event categories are not explicitly linked to the drug-related primary endpoint, and overlap among event categories is not described.

Finally, the registry does not report a multiplicity strategy, subgroup analyses, or a rationale for the study’s sample size. Its planning assumptions are illustrations, not evidence of the study’s observed precision or power. These reporting gaps constrain interpretation; they should not be filled by assumptions about the protocol or analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: PMS of Trazenta on the Long-term Use as Add-on Therapy — NCT01904383.
• Registry record last updated 2019-10-02; status last verified 2019-09.
• Results first posted 2019-10-02.
• 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.

18. Record Summary

NCT01904383 is a completed post-marketing surveillance study sponsored by Boehringer Ingelheim. It examined long-term Trazenta tablets as add-on therapy in patients with type 2 diabetes mellitus. The recorded start date is 2013-07-01, primary completion date is 2018-10-04, and enrollment is 4057.

The primary outcome is the percentage of participants with drug-related adverse events in a defined safety set, over the period from first to last drug administration, up to approximately 156 weeks. The registry lists HbA1c change as a secondary outcome. It reports serious and other adverse-event counts, along with selected serious-event terms, but does not report numerical results for either listed outcome or any statistical analyses. Allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. The available findings are therefore descriptive and do not establish a comparative treatment effect or causation.