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 Immune Response to the Human Papillomavirus Vaccine in Young Women With Inflammatory Bowel Disease (NCT01034358), a na phase 4 study. The primary outcome is Twelve Month Antibody Response to the Human Papillomavirus (HPV) Vaccine (Geometric Mean Titers [GMT]).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01034358 |
| Phase | Phase 4 |
| Condition | Inflammatory Bowel Disease, Uterine Cervical Dysplasia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 15 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
Young women with inflammatory bowel disease (IBD), as described in the study title and summary. The registry record does not report further eligibility details or the characteristics of participants in the enrolled group.
Intervention
The Human Papillomavirus Vaccine, identified in the study description as Gardasil. It was administered in 3 doses at baseline, 2 months, and 6 months.
Comparator
No concurrent comparator group is described in the registry record. Although the official title refers to young women with and without IBD, the recorded model is single group and allocation is listed as NA. A comparison with women without IBD is therefore not available in the recorded design.
Primary question
What antibody response to the HPV vaccine was measured at one year in young women with IBD? The primary outcome is the geometric mean titer (GMT) of anti-HPV levels, expressed in mMU/mL. The registry record does not report a GMT estimate or its confidence interval.
The study rationale raises the possibility that IBD or immunosuppressants used to control IBD could be associated with a weaker vaccine response. That is the question motivating the study, not a result established by the posted data. With no recorded comparison group and no posted antibody analysis, the registry record cannot establish whether responses differ between women with and without IBD, or whether any response is associated with immunosuppressant use. It records a vaccine administration schedule and a planned one-year antibody endpoint, but not an estimate that answers those comparative questions.
3. Trial Design
The registry record identifies this as a Phase 4, single-group study with enrollment of 15. Allocation is listed as NA, and masking is listed as none. The intervention is the Human Papillomavirus Vaccine, described as Gardasil, administered in 3 doses: at baseline, 2 months, and 6 months. The study status is completed. Its recorded primary outcome is antibody response at one year.
The official title refers to a comparison of young women with and without IBD, but the registry’s recorded model is single group and the record does not describe a control arm. The absence of a concurrent group matters: the recorded design can describe outcomes among participants receiving the vaccine, but it does not provide a like-for-like comparison with women without IBD. The record also does not describe randomization or a matching procedure.
Masking is listed as none. The registry record does not report a more detailed protocol for outcome assessment, a statistical analysis plan, or a sample-size justification. It gives the study start as 2010-02 and primary completion as 2011-06. Completion status indicates the study is marked completed in the registry; it does not itself establish that results were posted or that the primary outcome was analyzed. The record lists one outcome measure and no analyses. Consequently, the design and measurement target can be described, but the registry does not provide an inferential result for the primary question.
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 | Human Papillomavirus Vaccine |
|---|---|
| STARTED | 15 |
| COMPLETED | 13 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | Human Papillomavirus Vaccine |
|---|---|
| Withdrawal by Subject | 1 |
| Protocol Violation | 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 | Human Papillomavirus Vaccine |
|---|---|---|
| Participants analysed | 15 | |
| Age, Categorical: <=18 years | Participants | 7 |
| Age, Categorical: Between 18 and 65 years | Participants | 8 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age Continuous | years | 19.3 (SD 3.68) |
| Sex: Female, Male: Female | Participants | 15 |
| Sex: Female, Male: Male | Participants | 0 |
| Region of Enrollment: United States | participants | 15 |
| Disease Activity at First HPV vaccine dose: Quiescent | participants | 9 |
| Disease Activity at First HPV vaccine dose: Active | participants | 6 |
6. Primary Endpoint
The registry lists the primary outcome as Twelve Month Antibody Response to the Human Papillomavirus (HPV) Vaccine (Geometric Mean Titers [GMT]), measured over One year.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | mMU/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Twelve Month Antibody Response to the Human Papillomavirus (HPV) Vaccine,” measured as geometric mean titers (GMT) at one year. Anti-HPV levels were determined by an assay conducted by Merck & Co, Inc. and expressed in milliMerck units per milliliter (mMU/mL). The registry lists a 95% confidence interval as the measure of dispersion.
In general, a geometric mean is useful for measurements that are positive and can vary across a wide range: it summarizes values on a logarithmic scale and then returns the summary to the original measurement scale. This can make it a more representative measure of a group’s typical level than an arithmetic mean when values are skewed. A confidence interval conveys uncertainty around an estimated group value; a narrower interval indicates greater precision, while a wider interval indicates less precision.
The registry record identifies the endpoint and its intended summary but does not report the GMT, confidence interval limits, or participant-level antibody values. It also does not state whether the endpoint was calculated from all participants, from those with an available assay, or from another analysis population. The endpoint definition alone therefore does not reveal the observed antibody response or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted record describes a one-group vaccine study in young women with IBD and identifies a one-year anti-HPV GMT as its primary outcome. It reports enrollment of 15 and a vaccine schedule of 3 doses at baseline, 2 months, and 6 months. However, it does not report the primary endpoint estimate, its 95% confidence interval, or an analysis. The antibody response itself is therefore not quantifiable from the registry record.
This absence is important for interpretation. Without a GMT estimate, the magnitude of the measured antibody level is unknown. Without confidence interval limits, its statistical precision cannot be assessed. The record also contains no analysis comparing the response with a group without IBD. Thus, the title’s comparative framing should not be read as evidence that a comparative analysis was conducted or that a difference was found.
The study summary gives a rationale: IBD or immunosuppressants used to control IBD might affect vaccine response. The registry outcome and design do not, by themselves, answer whether either factor is associated with antibody levels. No results are reported by IBD characteristics or immunosuppressant use. Such associations should not be inferred from the study rationale.
The safety record lists 0 serious adverse events among 15 at risk and 13 other adverse events among 15 at risk. These are the recorded counts for the vaccine group. The record does not list serious adverse event terms, and the death count is not reported as a numerical value. The safety counts should be read as registry entries, not as proof that every event was caused by vaccination or that unlisted events did not occur.
Overall, the registry record supports a description of what the study set out to measure and records selected safety counts. It does not support a conclusion about the size or precision of the antibody response, a comparison with women without IBD, or a relationship between response and immunosuppressant use. The completed status does not fill those gaps: the primary result and analysis remain not reported in the registry record.
9. Statistical Methods Explained
The statistical information recorded for this study is limited. The registry describes a single-group model, one primary outcome, a geometric mean titer with a 95% confidence interval, and no posted analyses. General statistical concepts can help explain what those measures would mean, but they cannot substitute for the absent result.
What does a geometric mean represent?
In general, a geometric mean summarizes positive measurements by taking their logarithms, averaging those transformed values, and converting the summary back to the original scale. This approach is often useful when measurements are right-skewed or span a broad range. It gives a group-level summary that is less dominated by very high observations than an arithmetic mean can be. The recorded anti-HPV measurement is expressed in mMU/mL, and the registry identifies GMT as the primary summary. The actual GMT is not reported in the registry record, so the observed level cannot be described.
How should a confidence interval be read?
In general, a confidence interval expresses uncertainty in an estimated parameter under the assumptions of the analysis. Its endpoints indicate a range of values compatible with the data and method at the stated confidence level. It is not a range containing a specified share of individual participants’ measurements, and it does not mean that the true value has a probability equal to the confidence level of lying within the particular interval after it has been calculated. The registry specifies a 95% confidence interval for the GMT, but reports neither endpoint. The degree of precision is therefore unknown.
What does the design allow?
A single-group design describes an outcome in the group that received the intervention. Without a concurrent comparison group, it cannot separate the group’s observed outcome from differences that might have occurred under another condition. In general, a comparison requires outcome data from both groups and a defined approach to estimating the contrast. The registry’s official title mentions women with and without IBD, but its recorded model is single group and no comparator group or comparative analysis is reported. The record therefore does not support a between-group estimate.
The record lists allocation as NA and masking as none. These entries describe aspects of the recorded design; they do not supply details about the outcome analysis. The registry does not report whether the antibody endpoint was adjusted for baseline measurements or other characteristics, how missing assay measurements were handled, or which participants were included in the primary analysis. Those details are not reported in the registry record.
Why can over-dispersion matter?
In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. If a model understates variability, its uncertainty estimates can be too small and its confidence intervals too narrow. The registry does not report an analysis model for the antibody outcome, its variability, or an assessment of over-dispersion. There is no basis to say that over-dispersion was present or how it was handled in this study. This concept is relevant as a general consideration, not as a finding about the trial.
What can planning calculations tell readers?
In general, sample-size calculations describe how many participants a future design might require under specified assumptions about the effect to detect, variability, significance level, allocation, and analysis method. They are planning illustrations, not observed evidence and not a measure of the probability that this completed study found a real effect. The registry’s stated illustration assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as stated fractions of an observed effect. The record does not report the trial’s own sample-size justification. Nor does it report an observed primary effect from which readers could evaluate the illustration’s empirical basis. Any hypothetical planning value should therefore not be treated as a result of this study or as evidence of observed power.
The registry records no analyses. It also does not state a testing procedure, an adjustment strategy, or a prespecified model for the primary endpoint. A confidence interval is named, but the method used to calculate it is not reported in the registry record. These gaps prevent an independent assessment of the analysis choices or their assumptions. The endpoint definition and design can be explained, but a statistical estimate cannot be reconstructed from the posted record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no analyses. It does not report a multiplicity plan, including whether any additional outcomes or subgroup questions were tested, or how multiple comparisons would be handled. A count of one registered outcome measure is not enough to determine whether the study protocol or analysis considered other endpoints. The handling of multiplicity is not reported in the registry record.
The record does not describe missing antibody measurements, withdrawals, protocol deviations, or the number of participants with an evaluable one-year assay. It also does not state how missing endpoint values were handled. The analysis population for the primary outcome is not specified. In general, missing outcome data can affect both the estimate and its uncertainty, particularly if availability is related to participant characteristics or outcomes. Without the extent and handling of missingness, readers cannot assess that possibility for this study.
No statistical analysis plan, interim analysis procedure, or sample-size justification is reported in the registry record. No interim analysis should be assumed. The completed status and enrollment figure do not establish which participants contributed to the endpoint analysis, whether all planned assessments were obtained, or why the registry does not contain an analysis. These details remain unknown.
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 |
|---|---|---|---|
| Human Papillomavirus Vaccine | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Human Papillomavirus Vaccine | 13 of 15 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Human Papillomavirus Vaccine |
|---|---|---|
| Site reaction | Skin and subcutaneous tissue disorders | 11 of 15 |
| Headache | General disorders | 6 of 15 |
| Malaise | General disorders | 5 of 15 |
| Nausea | Gastrointestinal disorders | 4 of 15 |
| Myalgia | Musculoskeletal and connective tissue disorders | 3 of 15 |
| Abdominal Pain | Gastrointestinal disorders | 1 of 15 |
| Lightheadedness | General disorders | 1 of 15 |
| Sore Throat | Gastrointestinal disorders | 1 of 15 |
The registry records 0 serious adverse events among 15 participants at risk in the Human Papillomavirus Vaccine group. It records 13 other adverse events among 15 participants at risk. These are counts in separate registry categories and should be read as recorded, not added together. The record does not list terms for serious adverse events. Its deaths entry is not a numerical count, so deaths are not reported as a numerical value in the registry record.
These entries do not identify whether an event was considered related to the vaccine, how events were defined or collected, or how long participants were monitored for safety. A count of 0 recorded serious events is not proof that no serious event could occur; it describes the registry entry for this group and record. Likewise, the count of other adverse events does not establish that the vaccine caused those events. The registry does not provide event descriptions or further context that would support a more detailed interpretation.
12. What the Result Does, and Does Not, Mean
This study’s registry record is informative about its general design and the outcome it intended to assess. It identifies young women with IBD, a Human Papillomavirus Vaccine intervention, a 3-dose schedule, and a one-year antibody endpoint summarized as a GMT with a 95% confidence interval. It also records selected adverse-event counts. These details define the question and give some context for reading the safety entries.
The record does not provide the primary GMT or confidence interval. It therefore does not show the measured antibody level or how precisely it was estimated. It does not report an analysis, and it does not describe a concurrent group of women without IBD. The study title’s comparison wording does not establish that the registry contains comparative data. No conclusion about a difference between women with and without IBD can be drawn from these entries.
The study rationale mentions IBD and immunosuppressants as possible reasons for a different response. The registry does not report results according to immunosuppressant use or other IBD characteristics. That proposed explanation remains a rationale rather than a demonstrated association in the posted data.
The safety entries are also limited in scope. The record lists 0 serious adverse events and 13 other adverse events, each with 15 participants at risk, but does not provide event terms or a numerical death count. The entries do not establish causation or describe the circumstances of the events.
In general, an outcome estimate and its uncertainty are needed to judge the magnitude and precision of a measured response. A comparison additionally requires outcome data from a suitable comparator group and an analysis of the contrast. Those elements are not reported in the registry record. The appropriate reading is therefore descriptive: the record states what was planned and includes selected counts, while the primary efficacy result and comparative evidence are unavailable.
13. Why This Trial Matters Statistically
This study raises a statistically important question about how to interpret an immune-response measure in a population for whom the investigators identified a possible concern: young women with IBD. The registry’s one-year GMT endpoint focuses on antibody levels, a quantitative measure that can be summarized using a geometric mean when values are positive and vary across a broad range. Specifying the measure and timeframe helps define what the study intended to learn.
The design details matter just as much as the endpoint. A single-group study can describe outcomes in the treated group, but it cannot directly estimate a contrast with women without IBD unless relevant comparator data are also collected and analyzed. The official title signals a comparison, while the recorded model and the absence of a comparator group in the registry record limit what can be concluded from the posted information. This illustrates why readers need to distinguish a research question from the design and results actually recorded.
The missing GMT and confidence interval also show why an outcome definition is not a result. Without an estimate, readers cannot assess response magnitude; without an interval, they cannot assess its precision. The record’s completed status and safety counts do not resolve either issue. Reporting the analysis, its population, and how missing measurements were handled would be necessary for a fuller statistical assessment.
For clinical researchers and biostatisticians, the central lesson is to separate study rationale, endpoint specification, design, and observed evidence. Each serves a different role. The registry identifies the intended antibody measure and records some safety information, but the absent primary analysis prevents a statistical conclusion about the measured response. Recognizing that boundary avoids turning a plausible hypothesis into a finding or treating an unreported estimate as evidence of no effect.
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 limitation for interpretation is that the registry record does not report the primary antibody result or its confidence interval, despite listing the endpoint. It also records no analyses. The magnitude and precision of the one-year GMT therefore cannot be assessed from the posted information.
The recorded design is single group, with no comparator group described. This limits the ability to interpret the outcome as a contrast between women with and without IBD, despite the comparative wording of the official title. The registry does not report an analysis by immunosuppressant use, so the rationale concerning these medications cannot be assessed as a study result.
Further participant and protocol details are not reported in the registry record. These include eligibility criteria beyond the description of young women with IBD, IBD subtype or severity, immunosuppressant exposure, and details of the assay beyond the assay attribution and measurement units. The record also does not state how many participants had an available one-year antibody measurement, how missing data were handled, or which analysis population was used.
The safety information is limited to counts in the serious and other adverse-event categories. Serious adverse-event terms are not listed, the death entry is not a numerical count, and event attribution and monitoring details are not reported. Enrollment of 15 also means that the recorded group is small; however, without outcome estimates or a comparison, the statistical consequences for the primary endpoint cannot be quantified. These limitations describe gaps in the registry record, not proof that the underlying study did not collect additional information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Immune Response to the Human Papillomavirus Vaccine in Young Women With Inflammatory Bowel Disease — NCT01034358.
- Registry record last updated 2012-10-23; status last verified 2012-09.
- Results first posted 2012-10-23.
- 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
The registry record identifies NCT01034358 as a completed Phase 4, single-group study sponsored by Mayo Clinic, with enrollment of 15. The study concerns the Human Papillomavirus Vaccine, described as Gardasil, administered in 3 doses at baseline, 2 months, and 6 months. The primary endpoint is the one-year anti-HPV geometric mean titer in mMU/mL, with a 95% confidence interval specified.
The record lists 0 serious adverse events among 15 at risk and 13 other adverse events among 15 at risk. Serious adverse-event terms and a numerical death count are not reported. Although the official title refers to women with and without IBD, the recorded design is single group and no comparator analysis is reported. The registry contains one outcome measure and no analyses; the primary GMT estimate and its confidence interval are not reported in the registry record.