Gastrointestinal and Health-related Quality of Life Outcomes in Patients With Simultaneous Pancreas-Kidney Transplants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Gastrointestinal and Health-related Quality of Life Outcomes in Patients With Simultaneous Pancreas-Kidney Transplants (NCT00267150), a non-randomized phase 3 study. The primary outcome is Changes in Gastrointestinal Symptom Severity and/or Health-related Quality of Life After Conversion From MMF to Enteric Coated Mycophenolate Sodium.

2. Clinical Question

The clinical question arises from the possibility of gastrointestinal complications during MMF-based immunosuppressive treatment. The registry describes two related aims: assessing whether conversion to EC-MPS is followed by changes in gastrointestinal symptoms or health-related quality of life, and determining the proportion of pancreas-kidney transplant recipients who experience gastrointestinal complaints while receiving MMF-based treatment.

These aims are not equivalent. A before-and-after assessment can describe how symptom scores change following conversion in the participants observed. It cannot, by itself, separate a change associated with conversion from changes that could occur over time for other reasons. The gastrointestinal complaint aim concerns symptoms during MMF-based treatment, while the primary outcome concerns change after conversion. The registry lists gastrointestinal symptoms under MMF-based immunosuppressive therapy as a secondary outcome, but does not report numerical outcome results for either aim.

Health-related quality of life appears in the primary outcome title and study summary, but the recorded unit and detailed scoring description concern the GSRS. The specific instrument, scoring method, and result for a separate quality-of-life measure are not reported in the registry record. Accordingly, the record supports a description of the intended clinical questions, not an estimate of symptom improvement or quality-of-life change.

3. Trial Design

The registry classifies the study as phase 3, completed, non-randomized, unmasked, and single-group. The listed enrollment is 31. The sponsor is Novartis Pharmaceuticals. The recorded study start is 2005-11 and primary completion is 2008-01. The listed intervention is enteric-coated mycophenolate sodium (EC-MPS), and the study concerns pancreas and kidney transplantation.

The study summary describes assessing gastrointestinal and health-related quality-of-life outcomes after a switch from MMF to EC-MPS, alongside the proportion of recipients experiencing gastrointestinal complaints under MMF-based immunosuppressive treatment. The primary outcome description specifies a baseline assessment at Visit 1 and a follow-up assessment at Visit 2, weeks 6-8. The study is single-group, so the registry record does not describe a concurrent control group. Random assignment and masking are also not part of the listed design.

This design can describe within-participant score changes over the interval between assessments, if those results are available. It does not create the like-for-like treatment comparison that random allocation to intervention and control groups would support. In particular, there is no listed group that remained on MMF for comparison over the same period. The record does not report a detailed protocol, the intended statistical analysis plan, the rationale for enrollment, or further information about participant eligibility and follow-up. Such design details should not be inferred from the phase or completion status.

The record lists two outcome measures and no analysis entries. It describes the primary measure and names a secondary outcome concerning gastrointestinal symptoms under MMF-based therapy, but does not give numeric outcome findings. Completion status indicates that the study is recorded as completed; it does not establish that all planned measurements were obtained or that every planned analysis was performed.

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

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Changes in Gastrointestinal Symptom Severity and/or Health-related Quality of Life After Conversion From MMF to Enteric Coated Mycophenolate Sodium, measured over weeks 6-8.

The primary outcome is titled as change in gastrointestinal symptom severity and/or health-related quality of life after conversion from MMF to EC-MPS. Its recorded unit is change in GSRS score. The scale is a 15-item instrument designed to assess symptoms associated with common gastrointestinal disorders. It has five subscales: reflux, diarrhea, constipation, abdominal pain, and indigestion. Each subscale has a mean score ranging from 1, indicating no discomfort, to 7, indicating very severe discomfort. The total score is computed as the mean of the subscale scores.

The primary analysis is described as comparing Visit 1 baseline with Visit 2 at weeks 6-8 by calculating the difference in total GSRS score. A score-based endpoint retains information about symptom severity rather than reducing the assessment to whether a participant did or did not report a complaint. The scale’s direction gives the score clinical meaning: higher values correspond to more severe discomfort. However, the registry does not state the subtraction order used to define the change, so the sign of a hypothetical change cannot be interpreted from the record alone.

The registry record does not report the baseline or follow-up means, the mean change, its standard deviation, a confidence interval, or a statistical test. It also does not report a numerical result for a distinct health-related quality-of-life instrument. Therefore, the endpoint description clarifies what was intended to be measured, but does not establish the size, direction, or precision of any observed change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a within-group change estimate?

A continuous outcome such as the GSRS total score can be described by a mean at baseline, a mean at follow-up, and a mean change. The mean summarizes the average score in the analyzed observations, while the standard deviation describes variation among individual scores around that mean. A mean change focuses directly on the paired before-and-after difference for participants with the required measurements. The registry says the primary analysis used the difference between baseline and the weeks 6-8 assessment, but does not report the resulting mean or standard deviation.

The exact change definition matters. A difference can be calculated in either order. Since the record does not specify whether baseline was subtracted from follow-up or follow-up from baseline, a positive or negative estimate cannot be assigned a direction of symptom improvement without further documentation. The underlying GSRS scale does indicate that higher scores correspond to more severe discomfort, but that fact alone does not define the sign convention for change.

What does a confidence interval contribute?

A confidence interval communicates uncertainty around an estimated effect. It is useful because a point estimate alone can make a result look more definite than the data warrant. A relatively narrow interval indicates greater precision under the model and assumptions used; a wide interval indicates that a broader range of effects remains compatible with the data. The interval also helps readers assess whether estimates consistent with small or clinically important changes are plausible. No confidence interval for the primary outcome is reported in the registry record.

A confidence interval does not repair limitations of the design. In a single-group before-and-after study, an interval can quantify sampling uncertainty in the measured change while leaving other sources of uncertainty, including time-related changes and uncontrolled influences, unresolved. Precision about a within-group change is not the same as precision about a causal treatment effect.

Why distinguish statistical significance from magnitude?

A statistical test addresses compatibility between observed data and a specified statistical model under a null hypothesis. A p-value, when available, is not the probability that the null hypothesis is true, nor is it a measure of the size or importance of a difference. Interpretation should consider the effect estimate, uncertainty, measurement scale, and study design together. The registry record does not report a primary outcome test or p-value, so no statement about statistical significance is possible.

For a symptom scale, the numerical size of a change would need to be interpreted in relation to the scale and a meaningful threshold, if one were defined. The registry describes the GSRS range and subscales but does not report a threshold for clinically important change. Such a threshold should not be inferred from the scale’s endpoints alone.

Why can over-dispersion matter?

For outcomes that count events, a simple model may assume that the variability is determined by the average count. Real clinical event counts can vary more than that assumption allows, a condition often called over-dispersion. If over-dispersion is ignored, uncertainty can be understated and inferential results may appear more precise than warranted. Analysts can use methods that allow extra variability when the outcome and data support them. This is a general statistical consideration; the primary outcome in this record is a continuous GSRS score, and the registry does not report an analysis method addressing over-dispersion.

How should planning illustrations be read?

Sample-size calculations can illustrate the number of participants per arm that might be required to detect an assumed effect under stated modeling choices. They are planning illustrations, not observed power and not evidence that a study had a particular probability of detecting an effect after it was completed. The assumptions listed for the illustration are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect.

Those assumptions describe a hypothetical two-arm planning exercise, while the registered study is single-group and non-randomized. The illustration therefore does not represent the study’s actual allocation or provide a direct evaluation of its design. The registry does not report the study’s own sample-size justification or planning assumptions. In addition, the primary outcome estimate needed to understand an effect-based illustration is not reported in the registry record. The planning output should not be treated as observed evidence, a post-hoc probability of success, or a substitute for the missing outcome estimate.

In general, the usefulness of a sample-size illustration depends on whether its target effect is meaningful and whether its assumptions fit the planned design and analysis. Changing the assumed effect or modeling assumptions can change the planning result. The registry’s description does not provide enough information to assess how the illustrative assumptions relate to the study’s original protocol.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Enteric Coated Mycophenolate-sodium")
n   <- c(30)
m   <- c(-0.46)
sp  <- c(0.71)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Enteric Coated Mycophenolate-sodium  30  -0.460  0.710  -0.725  -0.195

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: the primary change in gastrointestinal symptom severity and/or health-related quality of life, and a secondary outcome concerning gastrointestinal symptoms under MMF-based immunosuppressive therapy. It does not report how these outcomes were handled together statistically, whether there were additional planned comparisons, or whether any adjustment for multiple testing was planned or used. The multiplicity strategy is not reported in the registry record.

Multiplicity matters when several outcomes or analyses are tested because the chance of at least one apparently noteworthy result can increase as the number of tests grows. A prespecified hierarchy or other adjustment can help control this issue, but no approach should be assumed for this study. The registry describes the primary outcome but does not report a detailed statistical analysis plan or the results needed to assess consistency across outcomes.

The record also does not report how missing outcome measurements were handled, whether participants with incomplete follow-up were included in the primary analysis, or how the analysis population was defined. The listed enrollment is 31, but this does not establish how many participants contributed data to each outcome or assessment. Missingness can affect both the amount of information available and the interpretation of a before-and-after estimate, particularly if participants with missing measurements differ from those with observed measurements.

The registry lists no analysis entries, and numerical results for the primary and secondary outcomes are not reported in the registry record. The reason analyses are absent is not reported in the registry record. It is therefore not possible to evaluate adherence to a prespecified analysis plan, determine whether outcome reporting was complete, or assess the influence of missing data and multiplicity on the findings.

12. Safety Results

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

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The adverse-event record lists 31 patients at risk for serious adverse events and 0 affected. In the separate other-adverse-event category, it lists 31 at risk and 2 affected. These are the recorded counts for the listed categories; they are not results for the GSRS endpoint and do not describe the severity or change in gastrointestinal symptom scores.

No serious adverse-event terms are listed. Deaths are not reported in the registry record. The record does not provide event descriptions for the 2 patients in the other category, the timing of events, their duration, or an assessment of relationship to treatment. It also does not report whether any events led to treatment discontinuation.

Safety counts require context. The at-risk count identifies the group represented in the event category, but does not by itself show the amount of observation time or establish that all participants were followed for the same duration. The registry’s event figures should therefore be read as recorded counts, not as a complete account of individual clinical courses or comparative safety. Because the study is single-group, these figures do not provide a randomized safety comparison with continued MMF.

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

The record establishes that a completed, single-group study was registered to examine gastrointestinal symptoms and health-related quality of life following conversion from MMF to EC-MPS in pancreas-kidney transplant recipients. It specifies a primary measure based on change in GSRS total score between baseline and weeks 6-8, and describes the scale’s symptom domains and scoring range. It also records enrollment of 31 and a secondary outcome concerning gastrointestinal complaints under MMF-based treatment.

Those details explain the intended measurement, but the primary outcome result is not reported in the registry record. Without baseline and follow-up scores, a mean change, and its uncertainty, the data documented in the record cannot establish whether symptoms changed, in which direction, or by how much. The record also does not report a numerical result for health-related quality of life or for the secondary gastrointestinal complaint outcome.

The absence of a reported result is not evidence that no change occurred. It also does not establish that a change occurred. The registry entry does not permit either conclusion. Completion status does not resolve this uncertainty because completion is a study status, not an outcome estimate.

The design further constrains what a result could show. A within-group change can describe how measured scores differ over time among observed participants, but without a concurrent comparison group it cannot isolate the effect of conversion from other influences. The study is non-randomized and unmasked, so treatment allocation and knowledge of treatment may also matter when interpreting any available findings. The registry does not report detailed analysis methods that would clarify how these issues were addressed.

The safety figures document 0 serious adverse events among 31 at risk and 2 affected in the other event category among 31 at risk. They do not answer the primary symptom question or establish a comparative safety profile. Overall, the record is informative about the study question, outcome definition, and design, while leaving the efficacy, precision, and quality-of-life findings unreported.

14. Why This Trial Matters Statistically

This study raises a statistical question that is common in clinical research: how to interpret a before-and-after change when there is no concurrent control group. A repeated measure can be useful because each participant’s baseline provides context for their follow-up score. But the change still combines any treatment-associated change with other changes that occur over time. Recognizing this distinction prevents a within-group result from being described as if it were a randomized treatment contrast.

The GSRS also illustrates the importance of matching statistical summaries to the measurement. Its total score combines five symptom subscales, each constructed from items about gastrointestinal experiences. Reporting a mean change would communicate average score movement, while variation and an interval would help show how consistently the participants’ scores changed. A scale score and a proportion reporting any complaint answer related but different questions; one should not be substituted for the other.

Another important issue is transparency about analysis. Outcome definitions alone are not enough to evaluate a result. Readers also need the estimate, a measure of its uncertainty, the analysis population, the handling of missing observations, and information about planned testing when multiple outcomes are involved. Those details are not reported in the registry record, so the clinical question can be described more fully than the statistical findings.

The contrast between the single-group study design and the two-arm assumptions used in the planning illustration is also instructive. Planning calculations depend on design and assumptions, and cannot be interpreted as proof of achieved power or as a result from the observed study. In this record, no primary outcome estimate is available to contextualize the effect-based illustration. The statistical value of the entry is therefore primarily in its documented question and measurement framework, alongside clear limits on what can be inferred from the posted results.

15. 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.

A central limitation is that numerical primary endpoint results are not reported in the registry record. There is no reported baseline score, follow-up score, mean change, standard deviation, confidence interval, or p-value. Thus, the magnitude, direction, and precision of the primary outcome cannot be assessed. Numerical findings for the secondary gastrointestinal symptom outcome and a separate health-related quality-of-life measure are also not reported in the registry record.

The design is single-group and non-randomized, with no listed concurrent control group. Any measured before-and-after difference would therefore be difficult to attribute specifically to conversion. The record also lists no masking. It does not report whether participants or outcome assessors were aware of treatment status at assessments, beyond the study-level masking classification, or how subjective reporting was handled.

Important analytical details are not reported in the registry record: the exact subtraction order for the change score, the statistical model or test, the definition of the analysis population, treatment of missing measurements, and the multiplicity approach. The entry does not report a threshold for clinically important change on the GSRS, limiting interpretation of any potential score difference in clinical terms.

The adverse-event entry provides category counts but not event descriptions, timing, follow-up duration, or treatment attribution. Deaths are not reported in the registry record. The enrollment value does not establish the number contributing data to each outcome or whether all planned assessments were completed. Finally, the rationale for the enrollment target and the study’s own sample-size planning are not reported in the registry record. These limits constrain interpretation of both benefit-related outcomes and safety, without implying that unreported outcomes were necessarily absent.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Gastrointestinal and Health-related Quality of Life Outcomes in Patients With Simultaneous Pancreas-Kidney Transplants — NCT00267150.
• Registry record last updated 2011-05-20; status last verified 2011-05.
• Results first posted 2010-12-24.
• 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.

19. Record Summary

The registry record describes a completed phase 3 study of conversion from MMF to EC-MPS in pancreas-kidney transplant recipients. It is listed as non-randomized, unmasked, and single-group, with enrollment of 31. The primary outcome concerns change in GSRS total score from baseline to weeks 6-8. The scale measures gastrointestinal symptoms across reflux, diarrhea, constipation, abdominal pain, and indigestion.

The registry lists two outcome measures and no analysis entries. It does not report numerical results for the primary GSRS outcome, the secondary gastrointestinal complaint outcome, or a separate quality-of-life measure. Serious adverse events are recorded for 0 of 31 at risk; other adverse events are recorded for 2 of 31 at risk. Deaths are not reported in the registry record. The available entry supports interpretation of the study’s question and design, but not an estimate of its primary outcome effect.