Gut Organoid and Microbiome Interactions in Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Gut Organoid and Microbiome Interactions in Hypertension (NCT04497727), a registered phase not stated study. The primary outcome is Differential Gene Expression in Gut Epithelium.

2. Clinical Question

3. Trial Design

This was a completed, non-randomized study of gut epithelial gene expression in people with hypertension and normotensive reference participants. It concerned adults undergoing routine screening colonoscopy who met eligibility criteria and gave written informed consent. Participants were categorized into groups according to blood-pressure status. The record does not describe an assigned therapeutic treatment or a randomized allocation process; it explicitly notes that the arms are not a like-for-like control comparison.

The registry enrollment is 35. The study description says that investigators compared basic properties of gut epithelia and examined whether there were fundamental differences between hypertension and normotension. Its specific focus was gene expression profiles of gut organoids derived from biopsy samples. The primary outcome description reports RNA sequencing of colonic epithelial tissue obtained during colonoscopy, comparing HBP participants with normotensive reference participants.

The registry lists Gene Expression as an intervention of type Other. That label describes the study’s measurement focus rather than a clinical treatment. The primary outcome was assessed at the time of colonoscopy, at a single visit. The record lists two outcome measures and zero analyses. Details of the eligibility criteria, blood-pressure classification procedure, laboratory workflow, and any prespecified statistical analysis plan are not reported in the registry record.

The study began on 2021-03-05, reached primary completion on 2022-04-08, and has status COMPLETED. The sponsor is the University of Florida. The record’s description of the normotensive and hypertensive group assignment is incomplete, so further details about recruitment, group composition, or matching cannot be established from the registry record.

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

Analysis population for the primary outcome, as defined in the registry: Colonic biopsies from HBP participants revealed 35 differentially expressed genes (29 upregulated, 6 downregulated) compared to normotensive subjects (reference group).

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 Differential Gene Expression in Gut Epithelium, measured over At time of colonoscopy (single visit).

The primary endpoint is the number of differentially expressed genes identified by RNA sequencing of colonic epithelial tissue obtained during colonoscopy. The comparison is between HBP participants and normotensive reference participants, and the timeframe is the colonoscopy visit. The registry reports 35 differentially expressed genes: 29 were upregulated and 6 were downregulated in the HBP group relative to the reference group.

A gene was classified as differentially expressed if it met both a statistical threshold—an FDR-adjusted p-value < 0.05—and a magnitude threshold—an absolute fold change ≥ 1.5. The endpoint therefore counts genes that pass the stated criteria; it is not a measure of the average size of a biological difference, the proportion of participants with a finding, or a clinical outcome.

Counting genes that meet defined criteria provides a way to summarize a broad molecular comparison. The count depends on the criteria used, the tissue and samples analyzed, and the underlying measurement and analysis procedures. The registry does not report gene-level estimates, uncertainty intervals, the identity of the genes, or details about how organoid measurements relate to the tissue-based endpoint. Those omissions limit interpretation of the count beyond the stated comparison.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a count derived from gene-expression testing. RNA sequencing measures patterns of RNA in a tissue sample, and a statistical comparison can assess whether measured expression differs between groups. In this study, the reported comparison was between colonic epithelial tissue from HBP participants and tissue from normotensive reference participants. The registry describes gut organoids derived from biopsy samples as part of the study’s focus, while the primary outcome specifically refers to RNA sequencing of colonic epithelial tissue. The relationship between these sample descriptions and the analysis is not reported in the registry record.

What does the gene count represent?

The reported count includes genes that met both the specified statistical and magnitude criteria. The registry states that genes were considered differentially expressed when the FDR-adjusted p-value was < 0.05 and the absolute fold change was ≥ 1.5. The resulting count is 35, with 29 upregulated and 6 downregulated in the HBP group relative to the reference group.

A count is a threshold-dependent summary. Changing the statistical threshold, fold-change requirement, sample set, or analysis method could alter how many genes qualify. A count also gives equal weight to each gene that passes, even though gene-specific estimates may differ in magnitude and precision. The registry does not report the gene-level results needed to examine those differences.

Why adjust for multiple testing?

General statistical explanation: when many hypotheses are tested, some may appear statistically significant by chance even if there is no underlying difference. A multiple-testing adjustment is intended to account for the collection of tests rather than treating each test as if it were the only one. False discovery rate (FDR) methods control the expected proportion of false discoveries among results declared significant, under the method’s assumptions. This differs from controlling the chance of any false positive across the full set of tests.

The registry states that an FDR-adjusted p-value threshold was used. It does not report the specific adjustment procedure, the number of genes tested, or the exact gene-level p-values. Thus, readers can identify the stated decision rule but cannot reconstruct or independently assess the adjustment from the registry record alone.

Why use a fold-change threshold as well?

General statistical explanation: statistical significance and magnitude answer different questions. A p-value is related to compatibility between observed data and a statistical model; a fold change describes a relative expression difference. Requiring both a statistical threshold and a minimum magnitude can screen out results that meet a statistical criterion but have small estimated changes. However, applying a magnitude cutoff does not itself establish biological importance or clinical relevance. The registry gives the absolute fold-change threshold but does not report gene-specific fold changes or confidence intervals.

What does over-dispersion mean in count data?

General statistical explanation: sequencing outcomes are often analyzed as count data, and over-dispersion occurs when observed variability is greater than expected under a simpler count model. Methods that account for over-dispersion can avoid treating the data as more precise than they are. The registry record does not identify the statistical model used, state whether over-dispersion was assessed, or describe how it was handled. No claim about the method used for this study can therefore be made.

The record reports zero analyses. It does not describe a model, covariate adjustment, handling of repeated or correlated measurements, missing-data approach, or analysis population. The reported gene count is therefore interpretable as the registry’s stated outcome, but the available method description is insufficient to reproduce the analysis or assess all modeling choices.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome uses an FDR-adjusted p-value threshold of < 0.05, indicating that the gene-expression comparison included a multiple-testing adjustment. FDR adjustment is generally used when testing many hypotheses, because interpreting each test in isolation can lead to an accumulation of false-positive findings. The registry does not report the adjustment procedure, the number of genes tested, the full set of results, or whether any other outcomes were included in a broader multiplicity strategy.

The record lists two outcome measures and zero analyses. It does not report whether the primary endpoint was prespecified in a protocol or statistical analysis plan, whether additional analyses were planned, or whether any interim analyses occurred. These details are not reported in the registry record, so it is not possible to assess whether the posted result reflects the complete planned analysis set or how outcome multiplicity was addressed beyond the stated FDR criterion.

Missing-data methods and analysis populations are not described. The registry does not state whether any participants or samples were excluded from the gene-expression analysis, how unusable or incomplete samples were handled, or whether all enrolled participants contributed to the primary result. The enrollment is 35, but the number of samples included in the primary analysis is not separately reported in the registry record.

These omissions matter because a gene-expression result can depend on which samples and tests enter the analysis. Without the analysis population, missing-data approach, full gene-level results, and planned analysis details, readers cannot fully evaluate selection, reproducibility, or the scope of multiplicity control. The stated threshold and reported count remain interpretable as posted, but the record does not support reconstruction of the underlying analysis.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event summary lists a hypertensive group with 16 participants at risk and a normotensive group with 19 participants at risk. For each group, the registry reports zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths. No serious adverse-event terms are listed.

These figures describe what was recorded for the groups in the adverse-event section. They do not establish that no adverse events could occur, nor do they provide detailed event definitions, collection procedures, or information about how completely events were monitored. The registry record does not report those details.

This was a study of participants undergoing colonoscopy and tissue sampling, not a randomized treatment comparison. The adverse-event counts should therefore not be interpreted as evidence comparing treatment safety between groups. The groups were classified by blood-pressure status, and the registry cautions that they are not a like-for-like control comparison. The figures are a descriptive record of the reported events, not a basis for attributing risk to an intervention.

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

The posted result documents a difference in gene-expression classification between the study’s hypertensive and normotensive reference groups: 35 genes met the stated criteria, with 29 upregulated and 6 downregulated in the HBP group. This is evidence of a molecular pattern in the tissue comparison as reported in the registry. It is not, by itself, evidence that hypertension caused those expression differences.

The result does not establish that the identified genes cause hypertension, explain its development, or predict future health outcomes. It does not show whether the expression patterns are specific to hypertension rather than other differences between participants. The record does not report gene identities, gene-specific estimates, confidence intervals, or adjustment for potential confounders, all of which would add context for interpreting the biological pattern.

The comparison was not randomized, and the registry explicitly cautions that the arms are not a like-for-like control comparison. Categorization by blood-pressure status supports a descriptive comparison, but it does not remove the possibility that other group differences contributed to the observed result. As the outcome was measured at the colonoscopy visit, the result also does not establish the timing or direction of any relationship between expression and hypertension.

The registry does not report a clinical endpoint, a treatment effect, or a follow-up outcome. The gene count should not be read as a measure of clinical benefit or harm. It is a threshold-based summary from a molecular analysis. The result may help characterize a research question about gut epithelium and hypertension, but confirmation, causal interpretation, and assessment of clinical importance require information and evidence beyond what is reported in this registry record.

13. Why This Trial Matters Statistically

This study illustrates a common challenge in molecular research: a single biological comparison can involve testing many genes, while the reported outcome condenses those tests into a count that depends on statistical and magnitude thresholds. The FDR-adjusted p-value criterion addresses multiplicity, and the fold-change cutoff adds a requirement for a minimum relative difference. Both rules shape which findings enter the reported count.

Reading the result statistically requires separating the number of genes passing a threshold from the size, precision, and biological meaning of each gene-specific result. A count of 35 is informative about how many genes met the stated criteria, but it cannot replace the full estimates and uncertainty measures. Those results, along with the testing and adjustment details, are not reported in the registry record.

The study also demonstrates why design matters when interpreting biological comparisons. Participants were classified by blood-pressure status rather than randomized, and the registry cautions against treating the groups as like-for-like controls. The molecular findings are therefore descriptive of the comparison and cannot isolate the effect of hypertension from other group differences on the information recorded.

Finally, a clear registry account of the analyzed samples, statistical model, missing-data handling, and gene-level results would help readers assess reproducibility and evaluate the scope of the findings. The record states the endpoint criteria and headline count, but leaves those details unreported. This distinction between a posted result and the supporting analytical detail is important when interpreting exploratory or hypothesis-generating molecular evidence.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry provides a concise description of the study but leaves important design and analysis details unreported. It does not give the full eligibility criteria, participant characteristics, blood-pressure classification method, or the number of samples included in the primary analysis. Although enrollment is 35, the analyzed sample count is not separately stated.

The group description is incomplete, ending before the full description of the hypertensive group. The record also warns that allocation is not stated and that the arms are not a like-for-like control comparison. Since the groups were defined by blood-pressure status, differences in other participant characteristics may contribute to the expression comparison; covariate adjustment or matching details are not reported.

For the primary endpoint, the registry gives the criteria and total counts but not the identities of the genes, gene-specific fold changes, confidence intervals, or individual adjusted p-values. It does not state how many genes were tested or identify the FDR procedure. The statistical model, laboratory quality-control procedures, and handling of over-dispersion are not reported in the registry record.

The record also does not describe missing-data handling, exclusions, the analysis population, or a statistical analysis plan. It does not report whether interim analyses occurred. The relationship between gut organoids derived from biopsies and the tissue-based RNA sequencing endpoint is not fully detailed. These limitations do not negate the posted count, but they restrict independent appraisal, reproduction, and assessment of the finding’s precision and generalizability.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Gut Organoid and Microbiome Interactions in Hypertension — NCT04497727.
• Registry record last updated 2025-09-29; status last verified 2025-08.
• Results first posted 2025-09-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT04497727, titled “Gut Organoid and Microbiome Interactions in Hypertension,” is a completed study sponsored by the University of Florida. The official title is “Gut Inflammation and Gut-Gut Microbiome Interactions in the Pathogenesis of Hypertension.” The registry lists enrollment of 35 and dates of 2021-03-05 for study start and 2022-04-08 for primary completion.

The study compared gene expression in colonic epithelial tissue from HBP participants and normotensive reference participants undergoing colonoscopy. The primary outcome was the number of genes meeting an FDR-adjusted p-value threshold of < 0.05 and an absolute fold-change threshold of ≥ 1.5. The registry reports 35 differentially expressed genes: 29 upregulated and 6 downregulated in the HBP group.

The study was not a randomized comparison, and the record cautions that its arms are not like-for-like controls. It lists two outcome measures and zero analyses. Serious adverse events, other adverse events, and deaths are each reported as zero in both groups. Details of the full analysis, gene-level findings, missing-data handling, and analysis populations are not reported in the registry record.