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 Gene Regulation by Thiazolidinediones (NCT00567593), a na phase 4 study. The primary outcome is PDK4 mRNA.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00567593 |
| Phase | Phase 4 |
| Condition | Inflammatory Bowel Disease |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | James Lewis |
| Results posted | Yes |
2. Clinical Question
Population
Participants with inflammatory bowel disease were the condition of interest. The record lists enrollment of 12 participants, but does not describe the characteristics of the participants or specify the population included in the primary outcome analysis.
Intervention
The intervention was rosiglitazone, described as an 8mg tablet once a day for 14 days. The study purpose was to determine the effect of rosiglitazone on genes of the colon.
Comparator
The study is recorded as a single-group study, with allocation listed as NA and no masking. The registry record does not report a separate control or comparison group. It therefore does not support a like-for-like treatment comparison.
Primary question
The listed primary outcome is PDK4 mRNA, measured in copies/nL at 14 days. The central question is whether this gene-expression measure changed following rosiglitazone exposure. The registry record does not report the measured value or a change from baseline, so the size or direction of any change cannot be described.
This question concerns a molecular measure in colon tissue rather than a reported clinical outcome. The registry identifies inflammatory bowel disease as the condition and gene regulation as the study purpose, but does not provide further detail about the disease population, tissue collection, or how the primary outcome was obtained. Those details are not reported in the registry record.
3. Trial Design
The registry describes a completed phase 4 study with a single-group model and no masking. Allocation is listed as NA. Enrollment was 12. The record lists a start of 2007-10 and primary completion of 2008-03, and gives the study status as completed.
All participants in the listed group received rosiglitazone, described as an 8mg tablet once a day for 14 days. The registry does not list a concurrent placebo group, untreated group, or active comparator. Since there is no reported comparison group, changes over time, if any, could not be contrasted in this record with changes under another assigned condition. The study should not be read as a randomized comparison.
The primary outcome is PDK4 mRNA in copies/nL, with a 14-day timeframe. Its summary parameter is the median and its dispersion is described as the full range. The registry lists one outcome measure and one analysis, but does not provide the outcome value, the analysis method, or the number of participants with outcome data. It is also not reported whether the listed timeframe reflects a post-treatment measurement alone or a comparison with a baseline measurement.
The protocol details needed to understand implementation are limited in the registry record. The method of participant selection, eligibility criteria, tissue collection procedures, adherence assessment, and any planned sample-size justification are not reported in the registry record. A sample-size calculation or justification should not be inferred from the enrollment figure.
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 | Rosiglitazone |
|---|---|
| STARTED | 12 |
| COMPLETED | 10 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | Rosiglitazone |
|---|---|
| Adverse Event | 1 |
| Physician Decision | 1 |
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 | Rosaglitazone |
|---|---|---|
| Participants analysed | 12 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 12 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 7 |
| Sex: Female, Male: Male | Participants | 5 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 3 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 7 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 2 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 |
| Race (NIH/OMB): White | Participants | 8 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 12 |
6. Primary Endpoint
The registry lists the primary outcome as PDK4 mRNA, measured over 14 days.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | copies/nL |
| Endpoint classification | not reduced to a single comparison |
PDK4 mRNA is the primary endpoint listed in the registry. It is a measure of the amount of messenger RNA associated with the PDK4 gene, expressed in copies/nL. In general, gene-expression measurements are used to describe molecular activity in a sampled tissue. They can address whether an intervention is associated with a change in a biological process, but they do not by themselves establish a change in symptoms, disease course, or other clinical outcomes.
The registry specifies a median as the summary measure and the full range as the measure of dispersion. In general, the median identifies the middle value after observations are ordered. The full range describes the span from the smallest to the largest observation, and can be sensitive to extreme values. These summaries can be useful when a distribution is skewed or when the sample is small, but the record does not explain why these summaries were selected.
The outcome timeframe is 14 days. The registry does not report the PDK4 mRNA median or range, nor does it state whether the endpoint represents a post-treatment value, a change from baseline, or another contrast. The endpoint's result and its precision therefore cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a focused molecular question: the effect of rosiglitazone on colon genes, with PDK4 mRNA named as the primary outcome at 14 days. It also records enrollment of 12 participants in a single-group study. However, it does not report the primary outcome result. No median, full range, estimate of change, confidence interval, or significance test result is available in the record. The direction, magnitude, and precision of the PDK4 mRNA finding therefore cannot be described.
The study design also limits what an observed before-and-after pattern could establish. With a single group and no reported control condition, changes during the study could not be separated from changes that might have occurred over time for other reasons. General factors such as natural fluctuation, measurement variability, concurrent care, and regression toward typical values can complicate interpretation of within-group change. This is a general limitation of uncontrolled designs, not evidence that any particular factor affected this study.
The registry lists the primary measure as a median with full range. In general, a median and range describe the distribution of observations in a different way from a mean and standard deviation. The median is relatively resistant to extreme observations, while the range displays the endpoints but does not show how observations are distributed between them. Without the actual summary values or participant-level data, neither the distribution nor the influence of individual observations can be evaluated.
The posted enrollment is not necessarily the number included in the outcome analysis. The analysis population and the number with available PDK4 mRNA measurements are not reported in the registry record. Missing outcome data could affect both the summary and its interpretation, but the record does not describe whether any measurements were missing or how missingness was handled.
Although the registry lists one outcome measure and one analysis, it does not describe the full set of outcomes, measurements, or statistical tests considered. The statistical plan, any adjustment for multiple testing, and any interim analyses are not reported in the registry record. A single listed outcome and analysis should not be taken as proof that no other analyses were performed.
The adverse-event information is separate from the molecular endpoint. The registry records no serious adverse events among 12 participants at risk and records other adverse events among 5 of 12 participants at risk. It does not provide the affected-event terms or a reported death count. These safety entries do not supply evidence about the PDK4 mRNA result. Overall, the registry record establishes the study question and basic design, but does not give the outcome data needed to judge the observed molecular pattern or its precision.
9. Statistical Methods Explained
The registry identifies the primary outcome's summary format, but does not name the statistical test or provide a statistical analysis plan. The method actually used to analyze PDK4 mRNA is therefore not reported in the registry record. The explanations below describe general statistical concepts relevant to the recorded outcome and design; they should not be mistaken for a description of analyses confirmed to have been performed in this study.
What does a median summarize?
In general, the median is the central observation after measurements are ordered. It is less affected by very high or low values than the arithmetic mean. For a small study, that can make the median a useful description when the distribution is asymmetric or contains extreme observations. But it does not show the full shape of the distribution or how many observations lie near the center. The registry specifies the median for PDK4 mRNA, but does not report its value.
What does the full range add?
In general, the full range gives the lowest and highest observed values. It makes the span of the data visible, but depends entirely on the two endpoint observations and may be strongly affected by unusual measurements. It does not indicate the density of observations within that span. The registry names full range as the dispersion summary, but gives no endpoints, so the observed spread cannot be assessed.
What would a confidence interval mean?
In general, a confidence interval expresses uncertainty around an estimate under specified assumptions and a specified analysis. A narrow interval indicates greater precision than a wide interval, but neither width nor interval location alone determines whether a result is clinically important. The registry record does not report a confidence interval for the primary outcome. It is therefore not possible to assess the precision of an estimated PDK4 mRNA value or change.
Why does the single-group design matter?
In general, a comparison group helps distinguish changes associated with an intervention from changes that could occur without it. In a single-group design, a measured value after exposure can describe the participants at that measurement time. If baseline measurements are also available, a within-group change can be calculated, but the change remains vulnerable to time trends and other explanations. The record does not specify whether a baseline PDK4 mRNA measurement was collected or analyzed. It reports no comparator, so a treatment contrast is not available in the registry record.
Allocation is recorded as NA and the model as single group. These design descriptors are consistent with the absence of a randomized arm comparison, but the registry does not provide additional allocation procedures. Masking is listed as none. The record does not say whether outcome assessors or laboratory personnel were masked separately, so no further masking detail should be inferred.
What can be inferred from the analysis count?
The registry lists one analysis and one outcome measure. Those counts describe what is listed in this record; they do not explain the model, test, covariates, handling of repeated measurements, or decision rule. In general, statistical methods should be interpreted alongside the estimand, the sampling process, and the assumptions of the selected method. These details are not reported in the registry record. The result cannot be reconstructed from the design description alone.
How should sample-size illustrations be read?
General planning calculations can illustrate how many participants per arm might be needed under stated assumptions. The listed illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. Such planning figures are hypothetical and are not the observed size or power of this single-group study. They do not establish the study's own design rationale. The sample-size justification for this study is not reported in the registry record, and the record does not give the observed primary effect needed to interpret the illustration as a direct estimate of a target effect.
Over-dispersion is a general issue when count outcomes vary more than an assumed statistical model allows. It can lead to uncertainty estimates that are too small if not handled appropriately. PDK4 mRNA is reported in copies/nL, but the registry does not state that a count model was used or that over-dispersion was assessed. No such method or assessment should be attributed to this analysis.
Likewise, p-values can be used in general to assess how compatible data are with a specified null model, given the assumptions of a test. They do not measure the probability that a hypothesis is true, and a small p-value does not establish clinical importance. No p-value or significance test is reported for the primary outcome. The statistical method, assumptions, uncertainty estimates, and interpretation of any test are therefore not available in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and one analysis, with PDK4 mRNA identified as the primary outcome. It does not report a broader statistical analysis plan, a hierarchy of outcomes, or whether additional gene-expression measures were collected or analyzed. The number of listed outcomes does not establish how many measurements, hypotheses, or exploratory analyses were considered in the full study.
In general, testing multiple outcomes or hypotheses can increase the chance of finding an apparently notable result by chance. Methods such as prespecifying a primary outcome or adjusting for multiple testing can address parts of this problem, but the appropriate approach depends on the analysis plan. Whether multiplicity was considered or addressed is not reported in the registry record. No adjustment method or rationale can be inferred.
The record does not state whether participants had missing PDK4 mRNA measurements, whether any participants withdrew, or how missing data were handled. It also does not identify the analysis population, such as whether all enrolled participants or only participants with complete measurements were included. These details matter because the analyzed group and missingness pattern can affect the estimate and its interpretation. They are not reported in the registry record.
Interim analyses and stopping rules are not reported in the registry record. The completed status does not, on its own, establish whether interim monitoring took place. The record also does not explain whether the single listed analysis was prespecified or conducted after data review. These omissions limit assessment of the analysis process, but do not establish that any particular procedure was or was not used.
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 | 0 | 12 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Rosiglitazone | 5 of 12 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Rosiglitazone |
|---|---|---|
| Nausea | Gastrointestinal disorders | 3 of 12 |
| fatigue | General disorders | 1 of 12 |
| Headache | General disorders | 1 of 12 |
| Diarrhea | Gastrointestinal disorders | 1 of 12 |
| pruritis | Skin and subcutaneous tissue disorders | 1 of 12 |
| Nasal Congestion | Respiratory, thoracic and mediastinal disorders | 1 of 12 |
| Tendonitis in R ring finger | Musculoskeletal and connective tissue disorders | 1 of 12 |
| Slight cold | Respiratory, thoracic and mediastinal disorders | 1 of 12 |
The registry records 0 serious adverse events among 12 participants at risk in the rosiglitazone group. It records other adverse events among 5 of 12 participants at risk. These are the event counts recorded for this group; they are not a comparison with another treatment or with an untreated group.
The record does not list serious adverse-event terms. It gives no details about the types, timing, severity, or relationship to rosiglitazone of the other adverse events. The death count is recorded as null, so deaths are not reported in the registry record. A missing death count should not be read as a reported count of zero.
In general, safety counts describe events observed and recorded in a study, but a small single-group study cannot by itself establish whether an event was caused by an intervention or how event occurrence compares with another condition. The registry entries should be read as descriptive counts, not as a causal or comparative safety estimate. The record does not provide further information to interpret the adverse events.
12. What the Result Does, and Does Not, Mean
The registry establishes that a completed, single-group study examined rosiglitazone in relation to colon gene regulation and listed PDK4 mRNA at 14 days as its primary outcome. It also specifies the planned summary as a median with full range. These details define the topic and outcome of interest, but they are not themselves evidence of an observed effect.
The primary outcome result is not reported in the registry record. Consequently, readers cannot determine whether PDK4 mRNA values were higher, lower, or similar after exposure, or how variable the measurements were. No confidence interval or statistical test result is reported either, so the precision and statistical uncertainty of any finding cannot be assessed.
Even if a within-group change were reported elsewhere, a single-group design would not provide a randomized comparison against a control condition. General explanations for change over time could not be ruled out on the basis of this design alone. The registry does not report a comparator, and it does not state whether a baseline value was included in the primary analysis.
The outcome is a molecular measure, not a reported clinical outcome. In general, evidence about gene expression can contribute to biological understanding, but it does not by itself establish effects on symptoms or disease outcomes. The registry record gives no clinical outcome result to interpret alongside PDK4 mRNA.
The adverse-event entries describe counts in the rosiglitazone group, without a comparison group or detailed event terms. They do not establish a causal relationship or a comparative risk. The record therefore supports a description of the study question, design, and recorded safety counts, but not a conclusion about the direction, magnitude, or clinical significance of a treatment effect.
13. Why This Trial Matters Statistically
This study is statistically notable for the gap between a clearly named molecular endpoint and the limited outcome information recorded in the registry. PDK4 mRNA is specified with a measurement unit, summary parameter, dispersion measure, and timeframe. Those details indicate what the primary outcome was intended to describe, but without its actual values they do not permit estimation or assessment of uncertainty.
The single-group design also makes the distinction between description and comparison especially important. A single-group study can describe observations in participants exposed to an intervention. It cannot, without a suitable comparator, isolate an intervention-associated change from time-related or other influences. This distinction applies even when the endpoint is measured precisely.
The registry lists one outcome measure and one analysis, but gives no analysis method, missing-data approach, or multiplicity plan. This illustrates why counts of listed outcomes or analyses are not substitutes for a statistical analysis plan. Prespecification and clear reporting help readers understand which results were intended to answer the primary question and how uncertainty was handled.
The safety information similarly shows the value of separating observed counts from comparative interpretation. The record contains counts for serious and other adverse events in one group, but no comparison group or detailed event terms. Descriptive safety entries should not be mistaken for evidence of causation or relative risk.
Overall, the record offers a useful example of how study design, endpoint definition, analysis reporting, and outcome availability jointly determine what can be concluded. Here, the endpoint is defined, but the outcome estimate and much of the analysis context are not reported in the registry record. Statistical interpretation must remain correspondingly limited.
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 interpreting the primary endpoint is that its result is not reported in the registry record. Although PDK4 mRNA, its unit, summary measure, dispersion, and timeframe are listed, no median or full range is available. There is therefore no direct estimate to interpret and no reported measure of precision.
The study is recorded as a single-group design without a reported control group. This prevents a like-for-like comparison and limits causal interpretation of any change that may have been observed. The registry does not specify whether the primary outcome was based on a post-treatment measurement alone or on a change from baseline.
Important details about the participants and measurement procedures are not reported in the registry record. These include participant characteristics, eligibility criteria, tissue collection, and the analysis population. The number enrolled is listed, but the number contributing primary outcome data is not given. Missing-data occurrence and handling are also not reported.
The statistical test, analysis model, uncertainty estimates, multiplicity approach, and any interim analyses are not reported in the registry record. The record lists one outcome measure and one analysis, but does not provide enough information to evaluate the assumptions or implementation of that analysis. A sample-size justification is also not reported.
The safety record has additional limits: serious-event terms are not listed, other event details are absent, and the death count is not reported. These entries cannot support comparative safety interpretation. Together, these limitations mean that the record describes the study question and some design and safety details, but does not establish the primary outcome finding.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Gene Regulation by Thiazolidinediones — NCT00567593.
- Registry record last updated 2016-08-01; status last verified 2016-07.
- Results first posted 2014-05-08.
- 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
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18. Record Summary
The registry lists a completed phase 4, single-group study of rosiglitazone for gene regulation in inflammatory bowel disease. Enrollment was 12; the start was 2007-10 and primary completion was 2008-03. The intervention was described as an 8mg tablet once a day for 14 days. Allocation was listed as NA and masking as none.
PDK4 mRNA in copies/nL at 14 days was the primary outcome, summarized by median and full range. Its result and the statistical analysis method are not reported in the registry record. The record lists no comparator, one outcome measure, and one analysis.
For safety, 0 serious adverse events were recorded among 12 participants at risk, and other adverse events were recorded among 5 of 12 at risk. Serious-event terms are not listed, and the death count is not reported. The record supports description of the study design and outcome definition, but not an assessment of the primary result's direction or precision.