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 Healthy Volunteer Short Chain Fatty Acid Study (NCT05254340), a na na study. The primary outcome is Fecal Inulin.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05254340 |
| Phase | NA |
| Condition | Healthy |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 29 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Indiana University |
| Results posted | Yes |
2. Clinical Question
Population
Healthy adult volunteers. The eligibility description specifies adults ages 18-75 years with no prior history of gastrointestinal diseases or symptoms.
Intervention
A one-time ingestion of a 10-gram dose of inulin, recorded as a dietary supplement.
Comparator
There is no separate comparator group. The registry record lists a single-group model and no allocation to study groups.
Primary question
The study aimed to evaluate fecal inulin content after inulin ingestion, as part of a proof-of-concept approach to measuring intestinal production of short chain fatty acids.
The central question is whether fecal inulin can be measured after the one-time ingestion in this healthy-volunteer study. The registry describes measurement of fecal inulin as a way to evaluate the study’s proposed approach; it does not report a comparison of different doses, treatments, or measurement strategies.
The primary outcome is fecal inulin content, measured in ug/1 mL extract over a timeframe of 4 days. The registry describes short acid hydrolysis and high-performance liquid chromatography as the measurement method. Bowel frequency, dietary intake, and bowel symptoms are listed as secondary outcomes, but numerical results for these outcomes are not reported in the registry record.
This is a measurement-focused research question, not a randomized treatment comparison. With no control group, the study cannot establish how fecal inulin measurements would differ in the absence of ingestion, or distinguish changes due to inulin from changes over time or other influences. The record also does not report a numerical estimate of fecal inulin or an analysis relating it to short chain fatty acid production. The study’s stated aim and the results available in the registry therefore need to be kept distinct: the former describes what the investigators sought to evaluate, while the latter do not include a reported primary-outcome summary.
3. Trial Design
The study is titled “Healthy Volunteer Short Chain Fatty Acid Study” and is described as a proof-of-concept healthy-volunteer study. Indiana University is listed as the sponsor. The registry lists the study as terminated, with a start date of 2021-08-01 and a primary completion date of 2023-07-31. Enrollment is listed as 29.
The registry describes one group of healthy volunteers and a single-group model. The eligibility description identifies adults ages 18-75 years with no prior history of gastrointestinal diseases or symptoms. Participants were to ingest a one-time 10-gram dose of inulin. There is no allocation to a separate control group, and masking is listed as none. The record therefore does not describe a randomized comparison or a like-for-like control group.
The primary outcome is fecal inulin content, with a 4-day timeframe. The registry describes the measurement procedure as short acid hydrolysis followed by high-performance liquid chromatography. Bowel frequency, dietary intake, and bowel symptoms are listed as secondary outcomes. Six outcome measures are listed overall, but the registry record does not provide numerical outcome summaries for them.
Some details that would clarify the design are not reported in the registry record. These include a reason for termination, further details of the study schedule and sample collection, the number of participants who completed each assessment, and a statistical analysis plan. The record does not state how the target enrollment was chosen or provide a sample-size justification. The fact that enrollment is listed does not, by itself, explain the planned analysis or establish how many participants contributed data to each outcome.
Because the study has one group, it is best interpreted as a small proof-of-concept measurement study rather than an efficacy trial. The design can describe observations made after inulin ingestion, but it cannot make a direct between-group comparison. The registry record also does not report an analysis that would support causal conclusions about inulin or measured short chain fatty acids.
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 | Healthy Volunteers |
|---|---|
| STARTED | 29 |
| COMPLETED | 22 |
| NOT COMPLETED | 7 |
Analysis population for the primary outcome, as defined in the registry: Fecal inulin was missing for 7 subjects who completed the study
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 | Healthy Volunteers |
|---|---|---|
| Participants analysed | 29 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 28 |
| Age, Categorical: >=65 years | Participants | 1 |
| Age, Continuous | years | 39.6 (SD 15.5) |
| Sex: Female, Male: Female | Participants | 13 |
| Sex: Female, Male: Male | Participants | 13 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 26 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 9 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 4 |
| Race (NIH/OMB): White | Participants | 13 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Fecal Inulin, measured over 4 days.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | ug/1 mL extract |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is fecal inulin content, reported in the unit ug/1 mL extract. The registry specifies a median and inter-quartile range as the summary format and gives a timeframe of 4 days. Fecal inulin was to be measured using short acid hydrolysis and high-performance liquid chromatography.
The endpoint is relevant to the study’s stated proof-of-concept aim: the investigators sought to evaluate intestinal production of short chain fatty acids through measurement of fecal inulin after a one-time ingestion of inulin. The endpoint recorded in the registry is fecal inulin content; it should not be mistaken for a direct numerical result for short chain fatty acid production. The record does not report a numerical primary-outcome summary or a relationship between fecal inulin and a separate measure of short chain fatty acids.
As general statistical context, the median describes the central point of a distribution when observations are ordered. The inter-quartile range describes the spread of the middle portion of those observations. These summaries are often useful when measurements are skewed or contain values far from the center, because the median and inter-quartile range are less influenced by extreme values than the mean and standard deviation. This general rationale does not establish the shape of this study’s data; the distribution is not reported in the registry record.
The primary outcome is missing for 7 subjects who completed the study. The registry record does not report the values that were observed among participants with available measurements, nor does it explain how missing primary-outcome data were handled in an analysis.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a single-group study of healthy adult volunteers who ingested a one-time 10-gram dose of inulin. Its primary outcome was fecal inulin content measured over 4 days. This describes the intended measurement and study question, but it is not a numerical finding about the amount of fecal inulin observed.
The registry record does not report a numerical summary for the primary outcome, such as a median or inter-quartile range. It also does not report an effect estimate, confidence interval, p-value, or analysis result for the primary outcome. As a result, the size and precision of any observed fecal inulin values cannot be evaluated from the registry record. No conclusion about the distribution of those measurements can be drawn from a summary that is not reported.
The record lists 29 participants enrolled, and states that fecal inulin was missing for 7 subjects who completed the study. It does not report the number with an available primary measurement, the reasons for missingness, or whether the missing observations were concentrated among participants with particular characteristics or experiences. These omissions matter because the observed measurements, if summarized only among participants with available data, may not describe all participants equally well when the reasons for missingness are related to the measurement or to other participant factors.
The single-group design also sets a limit on interpretation. Without a separate comparator, the registry record cannot support a direct estimate of how the endpoint would differ under another condition or in the absence of inulin ingestion. A measurement after ingestion can be described within the study group, but a before-and-after or causal interpretation would require the corresponding measurements and analysis. Those details are not reported in the registry record.
The study’s stated goal links fecal inulin measurement to a proposed approach for evaluating intestinal production of short chain fatty acids. However, the registry does not report a numerical primary-outcome result or an analysis validating that relationship. The aim should therefore be read as the purpose of the study, not as evidence that the measurement approach was established or that any particular level of short chain fatty acid production was observed.
The registry lists six outcome measures and no analyses. It names bowel frequency, dietary intake, and bowel symptoms as secondary outcomes, but does not report their numerical results or how they were analyzed. The available safety record lists no serious adverse events, other adverse events, or deaths among 22 participants at risk. Those entries describe the recorded safety counts, not a guarantee that no risk exists.
Overall, the registry record provides useful design information and identifies missing primary-outcome data, but does not contain the numerical outcome reporting needed to judge the observed endpoint values or their precision. This is a limitation of what can be interpreted from the record, rather than evidence for or against the study’s proposed measurement approach.
9. Statistical Methods Explained
The registry describes a single-group study and reports fecal inulin as the primary outcome. It specifies a median and inter-quartile range, a unit of ug/1 mL extract, and a 4-day timeframe. Numerical results and analyses are not reported in the registry record, so the statistical concepts below explain how these methods are generally interpreted rather than describing calculated findings from this study.
What does a median describe?
As a general statistical concept, the median is the central observation after measurements are ordered. It gives a measure of location that is less sensitive than a mean to a small number of unusually high or low observations. For a biological measurement, this can be helpful if the distribution is skewed. A median alone, however, does not show how variable the measurements are, how many observations were available, or how precisely the central value has been estimated. Those details require a reported spread measure and, where appropriate, an uncertainty interval.
What does an inter-quartile range add?
In general, the inter-quartile range describes the spread of the central portion of a distribution, from the lower quartile to the upper quartile. It is commonly paired with a median because both summarize a distribution without requiring it to be symmetric. It does not show the full range of values, and it does not by itself provide a confidence interval for the median. The actual median and inter-quartile range for fecal inulin are not reported in the registry record.
What does a confidence interval mean?
As general statistical context, a confidence interval expresses uncertainty around an estimate under a specified statistical procedure and its assumptions. A narrower interval indicates greater precision than a wider interval for the same estimand and method. An interval does not guarantee that the true value lies within its endpoints, and its interpretation depends on how the estimate and interval were calculated. The registry record does not report a confidence interval for the primary outcome, so its precision cannot be assessed through an interval estimate.
Why does the single-group design matter?
A single-group study records outcomes in one group rather than estimating a contrast between a study group and a comparator. A within-group summary can describe observed measurements, but it cannot directly answer what would have happened to the same population under an alternative condition. If a study has no comparator, observed values may reflect the intervention, natural variation, measurement conditions, or other influences. This is a general limitation of single-group designs, not a finding about the actual measurements in this study.
The registry lists no allocation to groups and describes no masking. It also lists a single-group model. The record therefore does not describe a randomized comparison or a blinded assessment. Whether other safeguards were used is not reported in the registry record. These design details are relevant to how measurement and selection could influence results, but they do not establish that any particular bias occurred.
How should planning illustrations be understood?
General sample-size illustrations can show how a hypothetical study’s size might depend on assumptions about a target effect, variability, statistical significance, and allocation. The planning assumptions associated with this record specify a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of an observed effect. These are planning assumptions, not evidence that this trial had two arms: the registry describes a single group. Such calculations are not observed power and do not replace a trial’s own sample-size justification. The sample-size justification and analysis plan are not reported in the registry record.
Over-dispersion is a general statistical issue in count data. It occurs when observed variation is greater than a model expects, and can make standard errors too small if the model does not accommodate that extra variation. The registry lists bowel frequency as a secondary outcome, but it does not report the form of that outcome data or a model used to analyze it. It is therefore not possible to determine whether over-dispersion was relevant to any analysis in this study.
For continuous measurements, skewness and unusual observations can affect summary measures and model assumptions. A median and inter-quartile range can describe a skewed distribution, but they do not tell a reader whether an inferential model was appropriate. The distribution of fecal inulin measurements, data diagnostics, and any model choices are not reported in the registry record.
Finally, a reported p-value would address compatibility of data with a specified null hypothesis under a statistical model; it would not, by itself, quantify the size or practical importance of a measurement. No p-values or inferential analyses are reported in the registry record. The record lists 6 outcome measures and 0 analyses, so interpretation should remain descriptive and limited to the design and safety counts that are explicitly recorded.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 6 outcome measures, including fecal inulin as the primary outcome and bowel frequency, dietary intake, and bowel symptoms as secondary outcomes. It lists 0 analyses. Numerical results for the secondary outcomes are not reported in the registry record, and a statistical analysis plan is not reported.
Multiplicity is a general issue that arises when several outcomes or hypotheses are examined. If multiple statistical tests are conducted, the chance of obtaining at least one apparently notable result can increase, depending on the testing strategy. Researchers may address this through a prespecified primary outcome, adjustment procedures, or a clearly defined hierarchy of analyses. Which, if any, of these approaches was planned or used is not reported in the registry record. The presence of multiple outcomes alone does not show that a multiplicity problem occurred; interpretation depends on the analyses actually conducted and reported.
Missing primary-outcome data are explicitly noted: fecal inulin was missing for 7 subjects who completed the study. The record does not give reasons for missingness, describe the characteristics of participants with missing values, or state whether any imputation or other missing-data method was used. It also does not report an analysis population definition, such as whether all enrolled participants or only participants with available measurements were intended for the primary analysis.
As general context, missing data can affect interpretation when the chance of a measurement being unavailable is related to the measurement itself or to participant factors. A complete-case summary may be informative, but its relevance to the full enrolled group depends on assumptions about why data are missing. Without the analysis method and information about missingness, the possible influence on the endpoint cannot be quantified. The registry record does not report a sensitivity analysis or other assessment of this 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 |
|---|---|---|---|
| Healthy Volunteers | 0 | 22 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Healthy Volunteers | 0 of 22 |
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 |
|---|---|
| Healthy Volunteers | 0 of 22 |
The registry’s safety record lists 22 participants at risk. It records 0 serious adverse events, 0 other adverse events, and 0 deaths. No serious adverse-event terms are listed.
These figures describe what is recorded for the safety group in the registry. They are counts, not estimates of the chance of an adverse event in other settings or populations. A count of zero means that no events in that category were recorded among the participants at risk in this record; it does not establish that the risk is absent. The record does not provide additional detail on the safety-monitoring procedures, event-collection period, or how events were defined.
The safety denominator is the listed group of 22 participants at risk, while enrollment is listed as 29. The registry record does not explain the relationship between those counts. It is therefore important not to treat the safety figures as if they necessarily describe every enrolled participant. The record also does not provide details of individual events because none are listed in the serious-event terms field.
These safety counts should be read separately from the primary endpoint. They do not provide information about the distribution or precision of fecal inulin measurements, and they do not resolve the missing primary-outcome data.
12. What the Result Does, and Does Not, Mean
The record establishes that this was a proof-of-concept, single-group study of healthy adults ages 18-75 years, with a one-time 10-gram ingestion of inulin and a primary outcome of fecal inulin content over 4 days. It identifies the laboratory measurement approach and reports that the primary outcome was missing for 7 subjects who completed the study. It also gives safety counts for 22 participants at risk.
The record does not report the numerical primary outcome, its median, or its inter-quartile range. It therefore does not allow a reader to quantify the observed fecal inulin measurements or their variability. Nor does it report a confidence interval or an analysis that would indicate the precision of an estimate. The absence of numerical results in the registry record is not a zero measurement, and it should not be interpreted as evidence that fecal inulin was absent.
The study’s stated purpose is to evaluate intestinal production of short chain fatty acids through measurement of fecal inulin. That purpose does not establish that fecal inulin is a validated measure of short chain fatty acid production. The registry record does not report a numerical relationship between fecal inulin and a separate measure of short chain fatty acids, nor does it give results that could demonstrate how well the proposed approach performed.
Because the study has no separate comparator group, it cannot directly estimate a contrast between inulin ingestion and another condition. The record also does not report a statistical analysis plan, an analysis population, or a reason for the terminated status. These omissions limit conclusions about how the study was analyzed and why it ended.
The zero adverse-event counts are limited to the recorded safety group and do not prove that the intervention has no risk. In the same way, the study’s design and stated aim do not establish a clinical benefit or support medical advice. The appropriate interpretation is narrow: the registry documents a measurement-focused study and some design and safety information, but does not provide the numerical outcome evidence needed to assess the primary measurement result.
13. Why This Trial Matters Statistically
This study matters statistically because it highlights the distinction between a research objective and an interpretable outcome result. The registry sets out a clear measurement aim—evaluating fecal inulin after a one-time ingestion—but the numerical primary-outcome summary is not reported. Without that summary, readers cannot assess the observed values, their spread, or the precision of a central estimate.
The study also illustrates how design determines which questions can be answered. A single-group design can characterize observations in the group studied, but it does not supply a direct contrast with a control condition. That limitation is especially important when a study’s broader motivation concerns a measurement approach: evaluating the measurements themselves is different from demonstrating a causal effect or validating a link to another biological quantity.
Missingness is another important statistical feature. Fecal inulin was missing for 7 subjects who completed the study, while enrollment is listed as 29. The registry does not report why these measurements were missing or how the missing values were handled. Those details affect how readers assess the representativeness and precision of any summary based on available data.
The record lists 6 outcome measures and 0 analyses, while the statistical analysis plan is not reported. This makes it difficult to determine how outcomes were intended to be summarized, whether any inferential comparisons were planned, or how multiple outcomes would be interpreted. The planning assumptions described for sample-size illustrations also use equal allocation between two arms, whereas the registered study is a single-group design. These assumptions should not be mistaken for the trial’s design or a justification of its enrollment.
More broadly, the record shows why complete statistical reporting matters in proof-of-concept research. Design details, outcome summaries, missing-data methods, and uncertainty estimates each answer different questions. Without the numerical results and analysis details, the study’s measurement findings cannot be independently interpreted from the registry record.
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 record does not report numerical results for the primary endpoint. Although the measurement unit, summary format, and timeframe are specified, the median and inter-quartile range are absent. Consequently, the observed level and variability of fecal inulin cannot be assessed.
Missing primary-outcome data are noted for 7 subjects who completed the study. The reasons for missingness and the handling of those values are not reported in the registry record. There is no reported analysis population definition, and no sensitivity analysis is described. These gaps prevent assessment of whether missing measurements could affect interpretation of an available-data summary.
The single-group design has no separate control group. The registry therefore does not describe a randomized comparison that could estimate a difference between inulin ingestion and a comparator condition. The record also does not report a numerical comparison before and after ingestion. Any such measures or analyses should not be presumed.
The study is listed as terminated, but the reason for termination is not reported in the registry record. A statistical analysis plan, sample-size justification, and details of any interim analyses are also not reported. The registry lists 6 outcome measures and 0 analyses, so the planned handling of multiple outcomes and the statistical methods used cannot be evaluated.
The stated aim concerns evaluating a proposed approach to measuring intestinal production of short chain fatty acids through fecal inulin measurement. The registry record does not report a separate numerical measure of short chain fatty acids or an analysis relating such a measure to fecal inulin. Therefore, the record does not provide results that establish the performance or validity of that approach. The safety record lists 22 participants at risk, which does not match the listed enrollment of 29; the registry does not explain the difference.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Healthy Volunteer Short Chain Fatty Acid Study — NCT05254340.
- Registry record last updated 2024-09-25; status last verified 2024-09.
- Results first posted 2024-09-25.
- 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
This terminated, single-group proof-of-concept study enrolled 29 healthy adult volunteers. The eligibility description specifies ages 18-75 years and no prior history of gastrointestinal diseases or symptoms. Participants were to ingest a one-time 10-gram dose of inulin. Indiana University is listed as sponsor.
The primary outcome was fecal inulin content, measured in ug/1 mL extract over 4 days using short acid hydrolysis and high-performance liquid chromatography. The registry specifies a median and inter-quartile range but does not report numerical primary-outcome results. Fecal inulin was missing for 7 subjects who completed the study. Bowel frequency, dietary intake, and bowel symptoms are listed as secondary outcomes.
The record describes no comparator group and lists 0 analyses. It lists 22 participants at risk for safety, with 0 serious adverse events, 0 other adverse events, and 0 deaths. The reason for termination, statistical analysis plan, sample-size justification, and handling of missing data are not reported in the registry record.