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 IMPENDIA- PEN VS Dianeal Only Improved Metabolic Control In Diabetic CAPD and APD Patients (NCT00567398), a randomized phase 3 study. The primary outcome is Change From the Baseline Value in HbA1c at Month 3 and 6.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00567398 |
| Phase | Phase 3 |
| Condition | ESRD, Diabetes |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 43 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Vantive Health LLC |
| Results posted | Yes |
2. Clinical Question
Population
Adults with ESRD and diabetes receiving Continuous Ambulatory Peritoneal Dialysis (CAPD) or Automated Peritoneal Dialysis (APD) were the intended population. The trial description includes people with Type 1 and Type 2 diabetes. The primary efficacy population was defined as randomized participants with a baseline HbA1c value and at least one PD exchange using study solution. This is narrower than simply all randomized participants.
Intervention
The glucose-sparing prescription used Physioneal, Extraneal, and Nutrineal. The study question concerns this combination of solutions as a prescription strategy, rather than an isolated comparison of any one product.
Comparator
The comparator was a non-glucose-sparing prescription using Dianeal only. The registry identifies the interventions and arm descriptions, but does not give further treatment-use details in the record.
Primary question
The primary question was whether the glucose-sparing prescription changed HbA1c differently from Dianeal alone at Month 3 and Month 6. HbA1c was assessed from baseline, with Month 6 identified as the end of study. The registry describes a pooled analysis including this trial and two other studies, so the primary outcome description is not limited to participants in NCT00567398. Numerical estimates and p-values for this comparison are not reported in the registry record.
3. Trial Design
NCT00567398 is a Phase 3 randomized, parallel-group trial with no masking reported. The registry lists enrollment as 43 and identifies ESRD and diabetes as the conditions under study. The record gives a start date of 2008-04, primary completion of 2011-07, and a completed status. These details describe the registered trial, but do not by themselves establish how many participants contributed to each reported analysis.
The study compared a glucose-sparing prescription—Physioneal, Extraneal, and Nutrineal—with Dianeal only. This is a comparison of prescription strategies rather than a single-drug comparison. The primary objective was to assess change from baseline in HbA1c, with measurements described at Month 3 and Month 6. The registry also lists secondary aims involving glycemic-control medication use, severe hypoglycemic events requiring medical intervention, metabolic measures, nutritional status, quality of life, and, in a subgroup, abdominal fat and left ventricular structure and function.
Important design details are not reported in the registry record, including the allocation ratio, the method used to generate or conceal random assignments, and any sample-size justification. The record says the trial was open label, but does not describe how that affected outcome assessment or other trial procedures. The primary outcome description identifies a pooled analysis of three studies, including NCT00567398. Consequently, the trial enrollment figure and the pooled outcome analysis describe different scopes, and should not be treated as interchangeable.
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.
Overall Study
| Stage | Non-Glucose Sparing Prescriptions | Glucose Sparing Prescriptions |
|---|---|---|
| STARTED | 127 | 124 |
| COMPLETED | 120 | 101 |
| NOT COMPLETED | 7 | 23 |
Reasons for not completing this period:
| Reason | Non-Glucose Sparing Prescriptions | Glucose Sparing Prescriptions |
|---|---|---|
| Adverse Event | 6 | 14 |
| Physician Decision | 0 | 4 |
| Withdrawal by Subject | 0 | 2 |
| Renal Transplantation | 0 | 3 |
| Other | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Primary Efficacy Intent-to-Treat (ITT) population included all subjects randomized with a minimum of a baseline HbA1c value determined and one PD exchange using study solution performed. The data in this outcome measure is a pooled analysis of the following 3 studies: NCT00567489, NCT00567398, NCT01219959.
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: The data represented in this module is a pooled analysis of the following 3 studies: NCT00567489 (protocol ID 31998), NCT00567398 (protocol ID 34202), NCT01219959 (protocol ID51067). Given that the glucose content of the PD solutions is similar, the pooling of the results were considered a valid method to answer the underlying research questions.
| Characteristic | Unit | Non-Glucose Sparing Prescriptions | Glucose Sparing Prescriptions | Total |
|---|---|---|---|---|
| Participants analysed | 127 | 124 | 251 | |
| Age, Continuous | years | 58 (SD 12.8) | 57.3 (SD 12) | 57.65 (SD 12.4) |
| Sex: Female, Male: Female | Participants | 59 | 64 | 123 |
| Sex: Female, Male: Male | Participants | 68 | 60 | 128 |
| Race/Ethnicity, Customized: Baseline – Asian | Participants | 41 | 42 | 83 |
| Race/Ethnicity, Customized: Baseline – Black | Participants | 1 | 0 | 1 |
| Race/Ethnicity, Customized: Baseline – Caucasian | Participants | 41 | 41 | 82 |
| Race/Ethnicity, Customized: Baseline – Hispanic | Participants | 32 | 31 | 63 |
| Race/Ethnicity, Customized: Baseline – Other | Participants | 12 | 10 | 22 |
6. Primary Endpoint
The registry lists the primary outcome as Change From the Baseline Value in HbA1c at Month 3 and 6, measured over Baseline, Month 3, Month 6 (End of Study).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Percent Change |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in HbA1c at Month 3 and Month 6, with Month 6 designated as the end of study. The registry describes the result as a mean with standard deviation and gives the unit as Percent Change. It describes HbA1c as glycohemoglobin and names a Tina-quant immunological assay suitable for samples from people with ESRD and with icodextrin metabolites, or an equivalent method.
HbA1c is used as a measure of glycemic control over time, making it relevant to the trial’s stated question about metabolic control. In general, a change-from-baseline endpoint compares a participant’s follow-up measurement with that participant’s starting value; a between-group contrast then asks whether the average change differs between treatment strategies. That general interpretation depends on the exact calculation used. The registry does not clarify how the stated Percent Change was derived from HbA1c values.
The endpoint description says adjusted least-squares comparisons between groups were estimated by visit, with p-values from an analysis of covariance testing whether the difference was zero. However, numerical means, standard deviations, adjusted differences, confidence intervals, and p-values are not reported in the registry record. The endpoint’s intended meaning can therefore be described, but the size and precision of the observed treatment contrast cannot be assessed from the record details available.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registered primary question concerns whether mean HbA1c change differed between the glucose-sparing prescription and Dianeal alone at the specified follow-up visits. The registry describes an analysis of covariance with least-squares comparisons by visit. This describes an analysis plan or method; it is not itself evidence about the direction, size, or statistical strength of the observed difference.
Numerical primary outcome results are not reported in the registry record. In particular, there are no group means or standard deviations, adjusted between-group estimates, confidence intervals, or p-values in the trial details. Without these values, it is not possible to describe whether the observed difference favored either prescription, how large it was, or how precisely it was estimated. A conclusion about statistical significance would also be unsupported.
The primary outcome description states that its data are pooled across three studies, including NCT00567398. This matters for interpretation: the pooled result, if considered, would not be attributable to this trial alone. The record does not give the contribution of each study or explain how the pooled analysis accounts for study-level differences. The trial’s enrollment figure is therefore not a substitute for the pooled analysis population.
In general, an adjusted least-squares difference expresses a model-based contrast between treatment groups, while a confidence interval would indicate the range of values compatible with the data under the analysis assumptions. Neither an estimate nor its interval is reported in the registry record. A p-value, even if available, would address compatibility with a null hypothesis under a statistical model; it would not by itself establish the clinical importance of a difference.
The registry lists secondary outcome topics, but does not report their numerical results in the registry record for this analysis. The posted information therefore supports a description of the research question, design, and planned statistical comparison, not a verdict on the effect of the prescriptions. Any interpretation should retain that distinction and account for the pooled primary analysis and the absence of reported estimates.
9. Statistical Methods Explained
The following explains the statistical concepts in general and relates them to the methods described in the registry record. The record says the primary analysis estimated least-squares differences between treatment groups by visit and used analysis of covariance (ANCOVA), with a p-value testing whether the difference was zero. It does not report the full model specification, covariates, or diagnostic checks.
What does change from baseline mean?
In general, a change-from-baseline outcome compares a follow-up measurement with a participant’s starting measurement. The study names baseline, Month 3, and Month 6 assessments of HbA1c. Comparing changes between groups asks whether the average movement from baseline differs between the prescription strategies. The registry gives the endpoint unit as Percent Change, but does not explain its calculation. That missing definition limits how precisely the reported scale can be interpreted.
What does ANCOVA do?
In general, ANCOVA models a follow-up outcome or change while accounting for one or more covariates. In a randomized trial, an appropriately specified model can improve precision by accounting for baseline outcome values or other prespecified factors. The registry identifies ANCOVA and least-squares group comparisons, but does not identify the covariates or say whether baseline HbA1c was included as a model covariate. Those details are not reported in the registry record and should not be inferred.
A least-squares estimate is a model-based mean or contrast, adjusted according to the variables included in the model. It is not necessarily the same as a raw difference between the observed group averages. The method can be useful, but its interpretation depends on the model terms, assumptions, and analysis population. The registry does not provide enough detail to reproduce the model or evaluate those choices.
What does the test of a zero difference mean?
In general, a test of whether a between-group difference equals zero assesses compatibility of the observed data with a null hypothesis of no difference, given the model assumptions. A p-value does not quantify the probability that the null hypothesis is true and does not measure the size or importance of an effect. A confidence interval, if reported, would communicate the estimate’s precision and the range of values compatible with the data under the chosen method. The registry describes p-values but does not report them or give confidence intervals for the primary comparison.
Why does the pooled analysis matter?
The primary outcome description says the data are pooled across three studies, including NCT00567398. General statistical interpretation of pooled data depends on whether study differences are represented appropriately and whether the studies address sufficiently similar questions. The record does not describe the pooling method, study-level terms, or each study’s contribution. It therefore does not support a detailed assessment of the pooled model. A pooled estimate should not be casually described as the estimate from this trial alone.
What can over-dispersion mean for event outcomes?
In general, over-dispersion occurs when event-count variability is greater than a simple statistical model expects. If present, it can make standard errors too small and uncertainty appear overstated. This concept can matter for count outcomes such as event frequencies, but the registry entries do not identify an over-dispersion analysis or provide enough event-outcome results to assess it for this trial. It should not be assumed to have occurred.
The registry also lists planning illustrations based on an observed effect, with stated assumptions of a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such calculations are general planning scenarios, not observed power and not evidence that the original trial was designed around those assumptions. The original sample-size justification is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint assessed at Month 3 and Month 6, alongside a range of secondary outcomes. It also reports 22 outcome measures and 73 analyses. When several outcomes, visits, or analyses are tested, the chance of obtaining at least one apparently unusual result by chance can increase. This is the general multiplicity concern; whether and how it applies depends on the testing strategy.
The registry record does not report whether the primary visits were treated as co-primary endpoints, whether a testing hierarchy was used, or whether any adjustment for multiple comparisons was applied. It also does not describe multiplicity control across the secondary measures. These details are not reported in the registry record, so p-values across outcomes should not be assumed to have a common interpretation or to be adjusted for multiple testing.
The primary efficacy population is defined as randomized participants with a baseline HbA1c value and at least one PD exchange using study solution. Although the population is called intent-to-treat, that eligibility rule excludes randomized participants who do not meet those criteria. The record does not give the number excluded or explain the treatment of participants with missing baseline or follow-up data.
Missing-data methods, including any imputation, model-based handling, sensitivity analyses, or reasons for missing assessments, are not reported in the registry record. The record also does not state whether the analysis followed assigned treatment regardless of subsequent treatment use. Those omissions prevent a complete assessment of how missing observations or departures from treatment assignment could affect the estimates.
The primary analysis is described as pooled across three studies, but the registry does not report how the pooled population was formed or how study membership was handled statistically. These details are relevant to both the population being analyzed and the interpretation of uncertainty.
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 |
|---|---|---|---|
| Non-Glucose Sparing Prescriptions | 41 | 127 | 32.3% |
| Glucose Sparing Prescriptions | 58 | 124 | 46.8% |
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 |
|---|---|
| Non-Glucose Sparing Prescriptions | 101 of 127 |
| Glucose Sparing Prescriptions | 98 of 124 |
Most frequent serious adverse event terms
| Event term | Organ system | Non-Glucose Sparing Prescriptions | Glucose Sparing Prescriptions |
|---|---|---|---|
| Peritonitis Bacterial | Infections and infestations | 5 of 127 | 8 of 124 |
| Fluid Overload | Metabolism and nutrition disorders | 3 of 127 | 5 of 124 |
| Peritonitis | Gastrointestinal disorders | 2 of 127 | 3 of 124 |
| Anaemia | Blood and lymphatic system disorders | 2 of 127 | 2 of 124 |
| Cellulitis | Infections and infestations | 1 of 127 | 3 of 124 |
| Gastroenteritis | Infections and infestations | 2 of 127 | 2 of 124 |
| Pneumonia | Infections and infestations | 2 of 127 | 2 of 124 |
| Hypertensive Crisis | Vascular disorders | 1 of 127 | 3 of 124 |
| Cardiac Failure Acute | Cardiac disorders | 1 of 127 | 2 of 124 |
| Catheter Related Complication | General disorders | 2 of 127 | 1 of 124 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Non-Glucose Sparing Prescriptions | Glucose Sparing Prescriptions |
|---|---|---|---|
| Peritonitis | Gastrointestinal disorders | 10 of 127 | 10 of 124 |
| Hypertension | Vascular disorders | 10 of 127 | 6 of 124 |
| Peritonitis Bacterial | Infections and infestations | 7 of 127 | 8 of 124 |
| Fluid Overload | Metabolism and nutrition disorders | 6 of 127 | 8 of 124 |
| Anaemia | Blood and lymphatic system disorders | 6 of 127 | 7 of 124 |
| Vomiting | Gastrointestinal disorders | 4 of 127 | 9 of 124 |
| Constipation | Gastrointestinal disorders | 4 of 127 | 8 of 124 |
| Oedema Peripheral | General disorders | 10 of 127 | 2 of 124 |
| Hypoglycaemia | Metabolism and nutrition disorders | 1 of 127 | 10 of 124 |
| Nausea | Gastrointestinal disorders | 6 of 127 | 4 of 124 |
Serious events with the highest arm-level rate: peritonitis bacterial (6.5%), fluid overload (4.0%), peritonitis (2.4%), cellulitis (2.4%), hypertensive crisis (2.4%).
The registry reports serious adverse event counts for Non-Glucose Sparing Prescriptions and Glucose Sparing Prescriptions. It lists 127 at risk and 41 affected in the non-glucose-sparing group, and 124 at risk and 58 affected in the glucose-sparing group. It also lists other adverse event counts of 101 and 98 affected, respectively, with the same at-risk counts. These are registry counts, not a complete description of event timing, duration, severity beyond the serious-event classification, or causal attribution.
Deaths are not reported in the registry record. The serious adverse terms listed with percentages are Peritonitis Bacterial (6.5%), Fluid Overload (4.0%), Peritonitis (2.4%), Cellulitis (2.4%), Hypertensive Crisis (2.4%), and Urinary Tract Infection (2.4%). The record does not provide enough detail to interpret these percentages’ denominators or establish comparative rates for each term.
The safety counts need particular caution because the primary outcome is described as pooled across three studies, while the trial record lists enrollment as 43. The registry does not explain how the safety groups relate to that enrollment or whether they use a broader pooled population. These figures should not be treated as a direct trial-only comparison without clarification. They also do not establish that an event was caused by a prescription.
12. What the Result Does, and Does Not, Mean
The registry record establishes the question that IMPENDIA was designed to address: whether a glucose-sparing PD prescription, using Physioneal, Extraneal, and Nutrineal, changed HbA1c differently from Dianeal alone in diabetic CAPD and APD patients. It also describes a randomized, open-label, parallel-group design and identifies the intended primary outcome and analysis approach.
It does not report numerical primary outcome estimates. As a result, the record does not establish the direction or size of an HbA1c difference, the precision of that difference, or whether it was statistically distinguishable from zero. It also does not permit an assessment of clinical importance. Those conclusions require results that are not reported in the registry record.
The pooled nature of the primary outcome analysis is another important boundary. The registry says the primary data combine three studies, including NCT00567398. A pooled estimate would describe that combined analysis, rather than necessarily describing this trial in isolation. The record does not explain the contribution of each study or how study differences were handled.
General statistical interpretation distinguishes an estimated effect from uncertainty about that estimate. A point estimate alone would not show precision; a confidence interval would help indicate the range of compatible effects. A p-value alone would not establish practical importance. Neither type of numerical result appears in the registry record for the primary endpoint.
Likewise, the listed adverse-event counts and terms describe registry safety reporting but do not establish causation or a direct treatment comparison. The record does not supply enough information to reconcile the safety-group counts with trial enrollment or the pooled outcome population. The appropriate conclusion is therefore limited: the registry describes a trial and its intended comparisons, but the numerical evidence needed to judge the primary outcome is not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically notable because its main question concerns a continuous clinical measure assessed repeatedly over follow-up and compared between randomized groups. Such a design makes the definition of change from baseline, the handling of baseline values, and the interpretation of visit-specific estimates central to understanding the result. The registry identifies ANCOVA and least-squares comparisons, but does not provide enough model detail to independently evaluate the analysis.
The primary endpoint is described as pooled across three studies, including NCT00567398. This raises a general issue of estimand and population: an estimate from a combined analysis may answer a broader question than the result from one registered trial. Clear reporting of the contributing studies, analysis population, and study-level modeling is important for readers to know what a pooled estimate represents. Those details are not reported in the registry record.
The record also shows why outcome reporting and multiplicity information matter. It lists many outcome measures and analyses, while not describing any adjustment or testing hierarchy. In general, readers need to know which comparisons were primary and how repeated testing was handled before interpreting p-values across a collection of endpoints.
Finally, the difference between the registered enrollment and the adverse-event group counts, together with the pooled primary analysis, makes population definitions especially important. The registry does not explain how those analysis populations relate to one another. This is not a basis for drawing conclusions about treatment effects, but it is a reason to read the record with attention to scope, denominators, and analysis methods.
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 central limitation for interpreting efficacy is that the registry entries do not include numerical results for the primary HbA1c endpoint. Group summaries, adjusted contrasts, confidence intervals, and p-values are not reported in the registry record. Consequently, the direction, magnitude, and precision of the primary comparison cannot be evaluated.
The primary outcome description states that it pools data from three studies, but the record does not explain how data were combined, how study membership was handled, or how much each study contributed. The result therefore cannot be attributed to NCT00567398 alone. The trial’s listed enrollment of 43 and the larger safety-group counts are not reconciled in the registry record.
The definition of Percent Change is not explained, and the ANCOVA model’s covariates and diagnostics are not reported. The record identifies a primary efficacy population with baseline HbA1c and at least one study-solution exchange, but does not give exclusions, missing-data methods, or sensitivity analyses. The intent-to-treat label should be read alongside that specific eligibility definition.
The record also does not report the allocation ratio, randomization and concealment procedures, sample-size justification, multiplicity strategy, or detailed treatment exposure. It describes an open-label trial, but does not explain whether outcome assessment was masked. These omissions do not prove that methods were inadequate; they mean that the registry record does not allow those features to be assessed.
Safety reporting is also difficult to interpret as a trial-only comparison because the relationship between the safety counts, enrollment, and pooled efficacy population is not explained. The registry does not report deaths and does not provide event-level timing or causal attribution.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: IMPENDIA- PEN VS Dianeal Only Improved Metabolic Control In Diabetic CAPD and APD Patients — NCT00567398.
- Registry record last updated 2025-07-22; status last verified 2025-07.
- Results first posted 2019-06-03.
- 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
NCT00567398 is a completed Phase 3 randomized, open-label, parallel-group trial in diabetic CAPD and APD patients with ESRD. The registry lists enrollment as 43 and compares glucose-sparing prescriptions using Physioneal, Extraneal, and Nutrineal with Dianeal alone.
The primary endpoint is change from baseline in HbA1c at Month 3 and Month 6. The registry describes ANCOVA and least-squares between-group comparisons by visit, and says the primary outcome data are pooled across three studies, including NCT00567398. Numerical primary outcome results are not reported in the registry record.
The record lists secondary metabolic, medication, hypoglycemia, nutrition, quality-of-life, and subgroup outcomes. It also gives adverse-event counts, but does not explain how their analysis population relates to trial enrollment or the pooled primary outcome population. Key details about missing data, multiplicity, model specification, and sample-size justification are not reported in the registry record.