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 Effects of Rosiglitazone on Renal Hemodynamics and Proteinuria of Type 2 Diabetic Patients With Renal Insufficiency Due to Overt Diabetic Nephropathy (NCT00324675), a randomized na study. The primary outcome is Proteinuria.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00324675 |
| Phase | NA |
| Condition | Type 2 Diabetes, Overt Diabetic Nephropathy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 28 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Technische Universität Dresden |
| Results posted | Yes |
2. Clinical Question
The trial asks whether rosiglitazone changes proteinuria and renal hemodynamic function in people with type 2 diabetes, renal insufficiency, and overt diabetic nephropathy. The registry record describes this as the study's hypothesis; it does not report results that would show whether the outcomes changed or how the groups compared.
Population
People with type 2 diabetes and renal insufficiency due to overt diabetic nephropathy. The primary outcome population is described as per protocol. Further eligibility criteria are not reported in the registry record.
Intervention
Rosiglitazone. The registry record identifies the drug but does not report the dose, dosing schedule, or other treatment details.
Comparator
Placebo. Details of the placebo and any other care received by participants are not reported in the registry record.
Primary question
How does proteinuria, measured in g/24hr, compare at baseline and after 6 and 12 mo of treatment? The registry record also identifies renal hemodynamics and renal function among the secondary outcomes, but does not report their results.
The central statistical question is about the pattern and precision of the outcome measurements over time, and whether the posted results support a difference between randomized groups. Without the outcome values, estimates of between-group effects, or uncertainty measures, that comparison cannot be assessed from the registry record.
3. Trial Design
The registry record describes a randomized, triple-masked, parallel-group trial, with rosiglitazone and placebo as the interventions. Enrollment was 28. The registry lists 14 participants at risk for serious adverse events in each group. The record marks the study as completed and gives a start of 2006-08 and primary completion of 2008-12. The phase is listed as NA.
Random allocation is intended to make treatment groups comparable on average at the start of a trial. A parallel-group design assigns participants to a group and follows each group separately. Triple masking indicates that the registry labels the study as masked at three levels, but the identities of the masked parties and the practical masking procedures are not reported in the registry record. The allocation sequence and the method used to conceal it are also not reported in the registry record.
The named sponsor is Technische Universität Dresden. The arm descriptions are blank, so details beyond the intervention names are not available in the registry record. The primary outcome is proteinuria, described as a mean in g/24hr and measured at baseline and after 6 and 12 mo of treatment. The primary outcome population is per protocol. The registry lists renal hemodynamic, renal function, adverse event, and HbA1c outcomes as secondary outcomes.
The record does not report how many participants completed follow-up, the number analyzed at each assessment, or the length of follow-up for each participant. It also does not report the planned sample size, eligibility criteria in detail, treatment adherence, or protocol deviations. Consequently, the design features that are recorded can be described, but important operational and analysis details cannot be evaluated.
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: 2 enrolled patients were excluded: one withdrew infromed consent, one developed anaphylactic reaction to sinistrin (used for renal function test)
Overall Study
| Stage | Rosiglitazone | Placebo |
|---|---|---|
| STARTED | 14 | 14 |
| COMPLETED | 13 | 14 |
| NOT COMPLETED | 1 | 0 |
Reasons for not completing this period:
| Reason | Rosiglitazone | Placebo |
|---|---|---|
| Adverse Event | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: per protocol
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 | Rosiglitazone | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 14 | 14 | 28 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 | 5 | 11 |
| Age, Categorical: >=65 years | Participants | 8 | 9 | 17 |
| Age Continuous | years | 65.4 (SD 9.6) | 66.5 (SD 8.5) | 66.1 (SD 9.1) |
| Sex: Female, Male: Female | Participants | 2 | 2 | 4 |
| Sex: Female, Male: Male | Participants | 12 | 12 | 24 |
| Region of Enrollment: Germany | participants | 14 | 14 | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Proteinuria, measured over at baseline and after 6 and 12 mo of treatment.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | g/24hr |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is proteinuria, measured in g/24hr. The registry describes the outcome as a mean and gives standard error as the measure of dispersion. Measurements were scheduled at baseline and after 6 and 12 mo of treatment, and the stated analysis population is per protocol.
Proteinuria refers to protein measured in urine. In a study of overt diabetic nephropathy, it is relevant because the registry frames proteinuria as one of the features of the condition and identifies changes in it as a central research question. A quantitative measure allows investigators to describe the amount measured and compare outcome patterns between treatment groups.
As a general statistical explanation, a mean describes the central value of a set of measurements. A standard error describes the precision of an estimated mean; it is not the same quantity as the spread of individual participants' measurements. Interpretation of a treatment comparison would normally depend on the group estimates, their uncertainty, and the analysis used to account for repeated assessments. The registry record does not report the proteinuria values, standard errors, treatment comparisons, or inferential results. The endpoint's definition is therefore available, but its observed pattern and precision cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically focused question: whether rosiglitazone is associated with changes in proteinuria and renal hemodynamic function in people with type 2 diabetes and overt diabetic nephropathy. It gives the primary outcome definition and its assessment schedule, but does not report the primary outcome values or an inferential comparison. No conclusion about the direction, size, or precision of a treatment-group difference can be drawn from the reported information.
The primary outcome is a continuous measure summarized as a mean with standard error. To interpret a comparison, readers would need the outcome estimates for each group at the relevant assessments, together with an effect estimate and its uncertainty, or another clearly described analysis. Those results are not reported in the registry record. There are no reported confidence intervals or p-values for the primary outcome, and no analysis entries are listed. This means the statistical evidence for a difference cannot be evaluated from this record; it does not establish that the groups were the same.
As a general statistical point, uncertainty matters alongside the estimated effect. A confidence interval, when reported, indicates a range of values compatible with the data and model at a stated confidence level. A narrow interval indicates greater precision than a wide interval, but neither can be interpreted without its estimate and analysis context. No such interval is reported for the primary endpoint in the registry record.
The endpoint is assessed at baseline and after 6 and 12 mo of treatment. Those repeated assessments could describe how proteinuria changes over time, but the registry record does not report the observed trajectory or the method used to compare groups across visits. It does not report whether the main comparison was based on change from baseline, follow-up values, or a model incorporating multiple visits. These approaches can answer related but distinct statistical questions.
The registry labels the primary analysis population as per protocol. That label does not, by itself, identify who was included or how participants with missing measurements or protocol deviations were handled. Those details are not reported in the registry record. The completed status and enrollment count describe the trial record, not the completeness or adequacy of its outcome data.
The safety entries report serious adverse events affecting 1 participant in the rosiglitazone group and 2 in the placebo group, with 14 participants at risk in each group. Other adverse events affected 12 and 9 participants, respectively. These are descriptive counts. Without further detail about event definitions, observation periods, participant-level overlap, and statistical comparisons, they do not establish a comparative safety effect.
Overall, the record documents the trial question, design labels, outcome schedule, and some adverse event counts. It does not provide the outcome results needed to estimate or interpret the primary treatment effect. Statistical conclusions about benefit, lack of effect, or equivalence are therefore not supported by the information reported in the registry record.
9. Statistical Methods Explained
The registry identifies randomization, masking, a parallel-group model, a continuous primary outcome, and a per-protocol primary outcome population. These labels describe aspects of the intended design and outcome summary. They do not provide the complete statistical analysis plan or the numerical results needed to evaluate the treatment comparison.
What randomization contributes
In general, randomization assigns participants to study groups using a chance-based process. Its purpose is to reduce systematic differences between groups at the point of assignment, including differences that may not be measured. It does not guarantee that the groups will be identical, particularly in a small study, and it cannot prevent differences that arise after allocation. The registry does not report the sequence-generation procedure, allocation concealment method, or baseline characteristics by group. Those details are not reported in the registry record.
What masking means
The study is labelled triple-masked. In general, masking is used to limit the influence that knowledge of treatment assignment may have on participants, clinical care, outcome assessment, or analysis. The registry does not identify which parties were masked or describe how masking was maintained. The label alone does not establish whether masking was successful.
How to read the continuous outcome
Proteinuria is reported as a mean with standard error. In general, the mean summarizes the central level of a continuous measure, while the standard error describes the precision of that estimated mean. Standard error should not be interpreted as the range of individual participant values. Individual measurements may vary more widely than the uncertainty around the mean.
A group mean at each assessment can describe the outcome, but a treatment effect requires a comparison between groups. Analysts may compare follow-up values, changes from baseline, or trajectories across repeated visits. These approaches have different assumptions and interpretations. The registry states that assessments occur at baseline and after 6 and 12 mo of treatment, but does not report which comparison was planned or performed.
Why repeated measurements matter
As a general statistical concept, measurements from the same participant over time are related rather than independent. An analysis that uses multiple visits should account for that within-participant relationship. The choice of model can affect the estimate and its uncertainty. The registry record does not report a repeated-measures model, a covariance structure, or another method for handling measurements across visits.
Standard errors, confidence intervals, and p-values are different ways of communicating uncertainty or evidence under an analysis model. A confidence interval describes uncertainty around an estimate; a p-value summarizes how compatible the observed data are with a specified null model. Neither is reported for the primary outcome in the registry record. Since the outcome estimates and analysis are also absent, there is no basis for reconstructing a treatment effect from the record.
Over-dispersion and model choice
As a general explanation, over-dispersion occurs when data vary more than a statistical model expects. If present, it can make standard errors from a model too small and results appear more precise than warranted. The appropriate response depends on the outcome and model, and might involve a different variance assumption or model. The primary endpoint is described as a continuous mean, and the registry does not report a fitted model or evidence of over-dispersion. It would therefore be inappropriate to assert that over-dispersion occurred or that a particular correction was used.
Planning illustrations are not trial results
Planning illustrations can show how sample size requirements change under chosen assumptions about an effect and statistical design. The stated assumptions for the planning illustrations are a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect set as a stated fraction of the observed effect. Such illustrations are conditional calculations, not evidence that the trial had a given probability of detecting an effect. They are not observed power. The registry record does not report a trial-specific sample-size justification, and the actual numerical planning estimates are not reported in the registry record.
The record lists 0 analysis entries. It also does not report the statistical test, model, covariate adjustment, handling of baseline values, treatment of missing observations, or multiplicity procedure. Without those details and the outcome estimates, readers cannot check the analysis assumptions or reproduce the primary comparison from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is measured at baseline and after 6 and 12 mo of treatment. The registry record also lists secondary outcomes for renal hemodynamic, renal function, adverse event, and HbA1c, and identifies 5 outcome measures. Multiple outcomes and assessment times can create multiplicity: when many statistical questions are examined, the chance of at least one apparently notable result can increase. As a general statistical matter, a prespecified hierarchy or adjustment procedure may be used to address that concern.
The registry record does not report whether analyses were prespecified by visit, whether one follow-up assessment was considered primary for inference, or whether any multiplicity adjustment was planned or applied. The recorded primary outcome is not reduced to one comparison because it has several categories or time points. No analysis entries or inferential results are reported, so the record does not allow readers to determine how the repeated assessments were handled.
Missing-data handling is also not reported in the registry record. It does not give the number of participants with measurements at each visit, reasons for missingness, methods used to address missing values, or sensitivity analyses. Missingness can affect both the estimate and its uncertainty, particularly when the likelihood of missing data is related to a participant's health or outcome. Without the extent and handling of missing data, the completeness of the primary analysis cannot be assessed.
The primary population is described as per protocol. The record does not define the criteria for inclusion in that population or report how it relates to all randomized participants. An intention-to-treat analysis, which in general retains participants in their assigned groups, is not described. It is therefore not possible to assess the consequences of the stated analysis population or the role of exclusions.
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 |
|---|---|---|---|
| Rosiglitazone | 1 | 14 | 7.1% |
| Placebo | 2 | 14 | 14.3% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Rosiglitazone | 12 of 14 |
| Placebo | 9 of 14 |
Most frequent serious adverse event terms
| Event term | Organ system | Rosiglitazone | Placebo |
|---|---|---|---|
| sleep apnoe | Respiratory, thoracic and mediastinal disorders | 1 of 14 | 0 of 14 |
| acute kidney injury | Renal and urinary disorders | 0 of 14 | 1 of 14 |
| atrial fibrillation with congestive heart failure | Cardiac disorders | 0 of 14 | 1 of 14 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Rosiglitazone | Placebo |
|---|---|---|---|
| peripheral edema | Skin and subcutaneous tissue disorders | 8 of 14 | 3 of 14 |
| anemia new or worsening | Blood and lymphatic system disorders | 4 of 14 | 4 of 14 |
| painful calf or foot | Musculoskeletal and connective tissue disorders | 3 of 14 | 1 of 14 |
| hypoglycemia | Endocrine disorders | 2 of 14 | 0 of 14 |
| hypotension | Vascular disorders | 2 of 14 | 0 of 14 |
| common cold | Infections and infestations | 1 of 14 | 1 of 14 |
Serious events with the highest arm-level rate: sleep apnoe (7.1%), acute kidney injury (7.1%), atrial fibrillation with congestive heart failure (7.1%).
The registry lists 14 participants at risk for serious adverse events in each group. Serious adverse events affected 1 participant in the rosiglitazone group and 2 participants in the placebo group. Other adverse events affected 12 participants in the rosiglitazone group and 9 in the placebo group. These are counts of affected participants, not a reported statistical comparison of risk.
The record also lists sleep apnoe, acute kidney injury, and atrial fibrillation with congestive heart failure, each with 7.1%. The denominator for these percentages and their attribution to a treatment group are not reported in the registry record. The death entries are not reported in the registry record.
As a general statistical point, adverse event counts should be interpreted in light of how events were defined and collected, the duration of observation, and whether participants could have more than one event. Those details and a formal comparison between groups are not reported in the registry record. The counts therefore describe the entries in the record but do not, on their own, establish that either intervention caused or prevented an event, or that the groups differed in safety.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, triple-masked, parallel-group trial compared rosiglitazone with placebo in people with type 2 diabetes and overt diabetic nephropathy. It identifies proteinuria as the primary outcome, measured in g/24hr at baseline and after 6 and 12 mo of treatment. It also records some adverse event counts and lists secondary outcome areas.
Those details do not answer whether proteinuria changed, whether the groups differed, or how precise any estimated difference was. The primary outcome values, group comparisons, uncertainty estimates, and analysis results are not reported in the registry record. The absence of those results in the record is not evidence that there was no treatment effect, nor is it evidence that the treatments were equivalent.
As a general statistical distinction, a nonsignificant result, if reported, would not by itself demonstrate equivalence. Equivalence requires a prespecified margin and an analysis showing that the uncertainty around the effect lies within that margin. The registry record does not report an equivalence margin or such an analysis. It also does not report a noninferiority framework.
The adverse event counts are descriptive. They do not account in the record for event duration, timing, participant overlap, or a statistical comparison. The percentage attached to each listed serious event term has no reported denominator or arm attribution. These entries should not be treated as a complete comparative safety analysis.
The appropriate conclusion is limited: the record documents the study's question and selected design and safety information, but does not report the primary efficacy results needed for statistical interpretation. No claim that rosiglitazone improved, worsened, or had no effect on the measured outcomes follows from the information recorded.
13. Why This Trial Matters Statistically
This trial raises a useful statistical question because it studies a continuous renal outcome over repeated assessments in a defined clinical population. Proteinuria is measured at baseline and after 6 and 12 mo of treatment, so interpretation depends not only on the numerical values but also on how within-participant measurements and between-group differences are analyzed.
The record also illustrates why a design label is not a substitute for a full analysis plan. Randomization, triple masking, and a parallel-group model convey important design information, but the record does not identify the randomization procedure, masked parties, primary comparison, or missing-data approach. These details determine how readers judge the strengths and limits of the evidence.
Multiplicity is relevant because the record identifies repeated assessment times and several secondary outcome areas. As a general principle, readers need to know which comparisons were planned and how multiple analyses were considered before interpreting isolated findings. The registry does not report a multiplicity strategy or analysis results.
The safety entries also demonstrate a distinction between describing counts and estimating comparative risk. Counts of participants with events can be informative, but their interpretation depends on event definitions, observation, and the analysis. The record does not supply those elements in enough detail for a comparative statistical assessment.
Most importantly, a completed trial record can document the research question and design without reporting the numerical results needed to answer that question. Here, the primary outcome definition is available, but estimates and uncertainty are not. Keeping that distinction clear prevents design information or descriptive safety counts from being mistaken for evidence about the primary treatment effect.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main trial-specific limitation for statistical interpretation is that the registry record does not report primary outcome values, treatment contrasts, uncertainty estimates, or analysis results. It therefore does not allow readers to assess the direction or magnitude of the proteinuria pattern, its precision, or the evidence for a between-group difference.
The primary outcome is assessed at multiple times, but the record does not report the planned or performed method for comparing those assessments. It also does not specify a single inferential comparison, a statistical model, adjustment for baseline values, or a multiplicity procedure. The record does not report handling of missing data, participant numbers at each visit, or sensitivity analyses.
Although the primary analysis population is described as per protocol, the criteria for that population and its relation to all randomized participants are not reported in the registry record. The number completing follow-up and the number included in each outcome analysis are also not reported. These omissions limit assessment of attrition, exclusions, and the potential effect of missing measurements.
Details of eligibility criteria, treatment dose, dosing schedule, allocation procedures, and masking implementation are not reported in the registry record. The arm descriptions are blank. These gaps limit evaluation of reproducibility and of how well the recorded design labels translate into trial procedures.
The safety record includes counts and listed serious event terms, but does not report event timing, definitions, group attribution for the listed percentages, or a comparative analysis. Death entries are not reported in the registry record. Taken together, these limitations mean the trial's recorded design can be described, but its primary efficacy findings and comparative safety cannot be fully evaluated from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Rosiglitazone on Renal Hemodynamics and Proteinuria of Type 2 Diabetic Patients With Renal Insufficiency Due to Overt Diabetic Nephropathy — NCT00324675.
- Registry record last updated 2011-11-02; status last verified 2011-10.
- Results first posted 2011-10-21.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00324675 is a completed, randomized, triple-masked, parallel-group trial sponsored by Technische Universität Dresden. The registry lists enrollment of 28, phase NA, a start of 2006-08, and primary completion of 2008-12. The interventions are rosiglitazone and placebo.
The primary outcome is mean proteinuria in g/24hr at baseline and after 6 and 12 mo of treatment, with standard error as the stated dispersion measure and a per-protocol population. Secondary outcome areas include renal hemodynamic, renal function, adverse event, and HbA1c.
The registry records serious adverse events affecting 1 participant in the rosiglitazone group and 2 in the placebo group, and other adverse events affecting 12 and 9 participants, respectively. It does not report primary outcome results or analysis entries. Details of missing data, statistical methods, and the primary between-group comparison are not reported in the registry record.