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 Special Investigation in Patients With Ankylosing Spondylitis (All Patients Investigation) (NCT01329380), a registered phase not stated study. The primary outcome is Number of Participants With Adverse Drug Reactions.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01329380 |
| Phase | Phase not stated |
| Condition | Ankylosing Spondylitis |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 403 |
| Arms in the primary outcome | n/a |
| Lead sponsor | AbbVie |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes participants with ankylosing spondylitis. Enrollment was 403, while the primary safety outcome specifies a safety analysis set. The reported safety group lists 396 participants at risk. How the enrolled population came to differ from the safety set is not reported in the registry record, so the two figures should not be treated as interchangeable or as evidence of a particular reason for exclusion.
Intervention
Participants received adalimumab (Humira) for ankylosing spondylitis as prescribed by their physician. The investigation sought information about adverse drug reactions that were not previously known, the incidence and circumstances of reactions in clinical practice, and factors that might affect safety and effectiveness. The registry describes treatment receipt; a specific dose or schedule is not reported in the registry record.
Comparator
No comparator group is described. Allocation is not stated, and the registry record explicitly cautions that the arms do not constitute a like-for-like control comparison. The registry entries therefore do not describe a randomized contrast or a controlled estimate of differences between treatments. They support a description of the recorded experience in the adalimumab group, not a comparative treatment effect.
Primary question
The primary endpoint is the number of participants in the safety analysis set with adverse drug reactions during 24 weeks. The registry defines an adverse drug reaction as an injury caused by taking a medication for which a causal relationship can be shown. The endpoint addresses whether such reactions were recorded, rather than estimating a difference from an untreated or alternative-treatment group. The numerical result for this primary endpoint is not reported in the registry record.
3. Trial Design
The registry describes a special investigation in participants with ankylosing spondylitis who received adalimumab as prescribed by their physician. Its stated purpose was to clarify adverse drug reactions in clinical practice, including reactions not previously known, the incidence and circumstances of reactions, and factors that might affect safety and effectiveness. The listed study status is completed. The listed start date is 2010-10-27, and the primary completion date is 2017-12-28.
Enrollment is reported as 403. The primary safety outcome refers to a safety analysis set, and the adverse event summary lists 396 participants at risk. The record does not explain the difference between enrollment and this safety group. It would be inappropriate to infer from these figures why particular participants were not included in the safety set, or whether the groups were defined at different stages.
The treatment group is described as participants with ankylosing spondylitis receiving adalimumab. The registry does not state allocation, and explicitly notes that the arms are not a like-for-like control comparison. A randomized design, a control regimen, and a protocol-defined allocation process are not reported in the registry record. Thus, the design information supports interpreting the results as a treatment-group safety description, not as a randomized comparison.
Secondary outcomes include the number of participants with a markedly improved or improved rating, the percentage with those ratings at the last visit by baseline factors, and change from baseline in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The record lists 7 outcome measures and 30 analyses. Details about visit schedules beyond the primary endpoint timeframe, the measurement procedures, and the analytic plan are not reported in 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
| Stage | Adalimumab |
|---|---|
| STARTED | 403 |
| Safety Population | 396 |
| COMPLETED | 374 |
| NOT COMPLETED | 29 |
Analysis population for the primary outcome, as defined in the registry: Safety analysis set
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.
Population: Safety analysis set
| Characteristic | Unit | Adalimumab |
|---|---|---|
| Participants analysed | 396 | |
| Age, Continuous | years | 46.3 (SD 15.6) |
| Age, Customized: 15 to < 65 years | Participants | 344 |
| Age, Customized: ≥ 65 years | Participants | 52 |
| Sex: Female, Male: Female | Participants | 130 |
| Sex: Female, Male: Male | Participants | 266 |
| Race/Ethnicity, Customized: Japanese | Participants | 396 |
| Region of Enrollment: Japan | participants | 396 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Adverse Drug Reactions, measured over 24 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with adverse drug reactions in the safety analysis set over 24 weeks. The registry defines an adverse drug reaction as an injury caused by taking a medication when a causal relationship can be shown. This definition distinguishes a reaction attributed to the medication from an untoward event for which such attribution has not been established. The endpoint is a participant count, not a count of all reaction episodes.
Counting affected participants is useful for describing how many people in the specified safety group had a recorded reaction during the stated timeframe. It gives a direct summary of the observed safety experience in that group. By itself, however, a count does not describe the range or severity of reactions, how often an individual participant experienced an event, or how the count compares with what would have occurred under another treatment. Those questions require additional outcome definitions or a comparison that the available record does not provide.
The primary endpoint’s numerical result is not reported in the registry record. The safety summary separately reports 17 participants in the serious adverse reaction grouping and 113 in the other adverse reaction grouping, among 396 participants at risk. Those subgroup summaries should not be substituted for the missing primary endpoint result: the primary outcome is defined as participants with adverse drug reactions, while the summary distinguishes serious and other groupings.
The registry also defines serious adverse drug reactions by listed clinical consequences, including death, life-threatening events, inpatient hospitalization or its prolongation, and persistent or significant disability or incapacity. This seriousness classification describes severity criteria; it does not on its own establish the frequency of every type of event or the causal certainty of any individual case.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record describes a safety investigation of adalimumab use in ankylosing spondylitis, with treatment taken as prescribed by the participant’s physician. It does not describe a randomized comparison or a like-for-like control group. The results therefore address recorded events in the treated group and cannot be read as an estimate of how the event frequency differs from another treatment or from no treatment.
The primary endpoint is the number of participants with adverse drug reactions over 24 weeks in the safety analysis set. Its numerical result is not reported in the registry record. The safety summary does report 17 participants in the serious adverse reaction grouping and 113 participants in the other adverse reaction grouping, with 396 participants at risk. These figures give information about the reported safety groupings, but they do not supply the missing primary endpoint count. Nor should the two group counts be combined: the record does not state that they are mutually exclusive or provide a rule for combining them.
The summary reports 0 deaths. The serious-term list includes bronchitis at 0.5%, and impetigo, infection, tonsillitis, dermatofibrosarcoma protuberans, and anaphylactic shock each at 0.3%. These values describe the listed terms as recorded; they do not establish that the terms account for all serious reactions. The registry’s definition of a serious reaction refers to clinical consequences, while listed event terms identify types of reported events. A term’s appearance in the serious list should not be taken as a complete clinical account of cases or as evidence about causation beyond the registry’s adverse drug reaction classification.
Precision cannot be judged from a confidence interval or other uncertainty estimate because such an estimate is not reported in the registry record. General statistical interpretation: a participant count is an observed summary for the specified group and timeframe. An interval estimate, when available, helps convey the range of values compatible with sampling uncertainty under the analysis assumptions. Without an estimate of uncertainty, the record does not quantify how precisely an underlying event frequency has been estimated.
The enrollment figure is 403, whereas the safety outcome lists 396 participants at risk. This difference is a reason to keep the analysis populations distinct, not a basis for guessing why they differ. The record does not report the primary endpoint count, a comparison group result, adjusted estimates, or the handling of incomplete outcome data. Consequently, the information supports a limited descriptive reading of the safety summaries, while key details needed for fuller interpretation remain unavailable.
9. Statistical Methods Explained
Statistical interpretation depends on what was counted, in whom, and over what timeframe. For the primary endpoint, the registry specifies a count of participants with adverse drug reactions, a safety analysis set, and a 24-week timeframe. That makes the target a participant-level event indicator: a participant either contributes to the count or does not, according to the endpoint definition. It is not a count of every episode, and it is not a rate per unit of follow-up time.
What does a participant count communicate?
A count is an easily interpretable summary of observed events in a defined group. It does not automatically express the probability of an event in a broader population, because the count depends on the size and composition of the group and on how events were collected and classified. A proportion can sometimes make counts easier to compare across groups of different sizes, but no primary endpoint proportion is reported in the registry record. No new proportion can be inferred from the reported count groupings without the matching event definition and analysis details.
The safety summary lists 396 participants at risk, 17 participants in the serious adverse reaction grouping, 113 in the other adverse reaction grouping, and 0 deaths. The primary outcome itself is described more broadly as participants with adverse drug reactions, and its result is not reported in the registry record. The serious and other group summaries therefore need to be read as the distinct classifications recorded, rather than as replacements for the primary endpoint. The record does not explain whether a participant could appear in more than one grouping.
Why does the comparison structure matter?
A treatment comparison estimates a contrast between groups, such as a difference in event frequency. Such an estimate requires comparable groups and a clearly defined comparator. The registry does not state allocation and warns that the arms are not a like-for-like control comparison. A descriptive count in the adalimumab group cannot isolate the effect of treatment from other influences, including participant characteristics, prescribing decisions, follow-up, or event recording. These are general considerations in interpreting non-comparative data; the registry does not report how each was addressed.
The record lists 30 analyses across 7 outcome measures. When many outcomes or analyses are examined, the chance of finding apparently notable results can increase if each is tested separately without accounting for multiplicity. General statistical practice may address this through prespecified priorities, adjustment procedures, or emphasis on estimation rather than isolated significance tests. The registry record does not report whether any such approach was used. A count of analyses alone does not show whether tests were conducted, whether results were selected, or whether multiplicity adjustment was needed.
What do uncertainty estimates add?
General explanation: a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the statistical method. A narrow interval indicates greater precision than a wide interval, while neither width nor location establishes causality. For a binary outcome, uncertainty depends in part on the number of observed events and the group size. The registry entries do not report a confidence interval for the primary endpoint, so its precision cannot be described numerically. A p-value, interval, or adjusted estimate for the primary endpoint is also not reported in the registry record.
How should planning calculations be read?
Any sample-size illustrations associated with the results are planning calculations based on an observed effect, not evidence that the study was designed prospectively to detect that effect. The stated assumptions for such illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These are assumptions for a planning exercise, not reported design features. They do not establish that this investigation had two randomized arms, and they are not observed power. Sample-size figures from a planning exercise are hypothetical participant requirements under assumptions, not counts of participants observed in the investigation.
For binary outcomes, the general meaning of a planning calculation is to relate a chosen event-frequency contrast, a target probability of detecting that contrast, and a significance threshold to the number of participants needed under the chosen model. Its relevance depends on whether the assumptions resemble the actual design and population. Here, the record does not report a randomized allocation or a like-for-like comparator, so a two-arm planning illustration should not be confused with the investigation’s actual structure.
Why can over-dispersion matter?
General explanation: some event-count models assume that variability follows a specified relationship to the mean. Over-dispersion occurs when the observed variability is greater than that assumption allows. If ignored, uncertainty estimates may be too small and statistical tests may appear more decisive than warranted. The primary endpoint is a participant count, and the registry entries do not report that an over-dispersion model was used. No conclusion about over-dispersion or model fit can therefore be drawn from the record.
In general, transparent reporting of outcome definitions, analysis populations, missing-data handling, and uncertainty estimates allows readers to assess how a result was obtained. For this investigation, the safety analysis set and timeframe are named, but detailed model choices, confidence intervals, missing-data methods, and the primary outcome count are not reported in the registry record. Interpretation should remain bounded by those reporting limits.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 7 outcome measures and 30 analyses. Multiple outcomes and analyses can create multiplicity concerns when many statistical tests are conducted: even if each test is interpreted using the same threshold, the chance of at least one apparently notable result may increase. This is a general statistical issue, not evidence that any particular result in this investigation is false. Whether the analyses were confirmatory, exploratory, or adjusted for multiplicity is not reported in the registry record.
The record identifies the primary outcome as the number of participants with adverse drug reactions in the safety analysis set over 24 weeks. It also lists secondary outcomes involving improvement ratings and BASDAI change. The hierarchy among secondary outcomes, the prespecified testing sequence, and any multiplicity procedure are not reported in the registry record. Without those details, the listed number of analyses alone cannot establish how statistical claims should be prioritized.
The difference between enrollment of 403 and the 396 participants at risk in the safety summary should be noted, but the reason is not reported in the registry record. The primary analysis population is identified as a safety analysis set. Rules for inclusion in that set, exclusions, withdrawals, missing visits, and missing endpoint data are not reported in the registry record. The handling of missing data—such as whether participants with incomplete follow-up were excluded, imputed, or assessed using another method—is also not reported.
These omissions affect how fully a reader can assess the potential for bias and the precision of the reported safety summaries. They do not justify assuming that missingness occurred in a particular pattern, or that a particular adjustment was or was not applied. No analysis population beyond the named safety analysis set can be reconstructed from the registry information.
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 |
|---|---|---|---|
| Adalimumab | 17 | 396 | 4.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Adalimumab | 0 of 396 |
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 |
|---|---|
| Adalimumab | 113 of 396 |
Most frequent serious adverse event terms
| Event term | Organ system | Adalimumab |
|---|---|---|
| Bronchitis | Infections and infestations | 2 of 396 |
| Impetigo | Infections and infestations | 1 of 396 |
| Infection | Infections and infestations | 1 of 396 |
| Tonsillitis | Infections and infestations | 1 of 396 |
| Dermatofibrosarcoma protuberans | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 396 |
| Anaphylactic shock | Immune system disorders | 1 of 396 |
| Myelopathy | Nervous system disorders | 1 of 396 |
| Upper respiratory tract inflammation | Respiratory, thoracic and mediastinal disorders | 1 of 396 |
| Colitis ulcerative | Gastrointestinal disorders | 1 of 396 |
| Gastric ulcer perforation | Gastrointestinal disorders | 1 of 396 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Adalimumab |
|---|---|---|
| Hepatic function abnormal | Hepatobiliary disorders | 12 of 396 |
| Nasopharyngitis | Infections and infestations | 12 of 396 |
| Rash | Skin and subcutaneous tissue disorders | 9 of 396 |
| Upper respiratory tract inflammation | Respiratory, thoracic and mediastinal disorders | 5 of 396 |
| C-reactive protein increased | Investigations | 5 of 396 |
| Gastroenteritis | Infections and infestations | 4 of 396 |
| Pruritus | Skin and subcutaneous tissue disorders | 4 of 396 |
| Injection site erythema | General disorders | 4 of 396 |
| Injection site reaction | General disorders | 4 of 396 |
| Alanine aminotransferase increased | Investigations | 4 of 396 |
Serious events with the highest arm-level rate: bronchitis (0.5%), impetigo (0.3%), infection (0.3%), tonsillitis (0.3%), dermatofibrosarcoma protuberans (0.3%).
The adverse event summary lists 396 participants at risk in the adalimumab group. It records 17 participants in the serious adverse reaction grouping, 113 in the other adverse reaction grouping, and 0 deaths. These are participant counts as reported, not counts of all event episodes. The registry record does not state whether participants could be included in both serious and other groupings, so those counts should not be added together.
The serious-event term list reports bronchitis at 0.5%; impetigo, infection, tonsillitis, dermatofibrosarcoma protuberans, and anaphylactic shock each at 0.3%. These are percentages attached to the listed terms. The registry record does not provide case-level detail, the number of events for each term, or enough information to infer the clinical course of individual participants. The listed terms also do not necessarily represent every serious reaction recorded.
Seriousness is defined by consequences such as death, a life-threatening event, inpatient hospitalization or its prolongation, and persistent or significant disability or incapacity. This classification is distinct from how common a term is. The absence of reported deaths in the summary does not erase other serious-event classifications, and the serious-reaction count should not be mistaken for the primary adverse drug reaction count, which is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The posted results give a descriptive account of safety outcomes in participants receiving adalimumab as prescribed by their physician. They report a safety group of 396 participants at risk, 17 participants in the serious adverse reaction grouping, 113 in the other adverse reaction grouping, and 0 deaths. They also identify several serious adverse reaction terms and their reported percentages. These figures help characterize what the registry recorded for the treatment group.
The results do not provide the numerical result for the primary endpoint, which is the number of participants with adverse drug reactions over 24 weeks. The serious and other reaction groupings are not interchangeable with that broader endpoint. Nor does the registry record establish that the two groupings are mutually exclusive. A complete estimate of the primary endpoint’s frequency or precision cannot be read from the reported safety figures.
The record does not describe a like-for-like control comparison. It therefore cannot establish how the observed event experience differs from that under another treatment or no treatment. In general, an event recorded after treatment does not by itself show that treatment caused the event; the registry’s definition of adverse drug reaction requires a causal relationship to be shown, but the available summary does not provide case-level assessment details.
The listed secondary outcomes concern improvement ratings and BASDAI change, but their numerical results are not included in the registry entries. No conclusions about those outcomes can be drawn from their names alone. Likewise, the absence of reported confidence intervals, missing-data methods, and detailed analysis procedures limits assessment of uncertainty and possible bias.
The findings should thus be understood as registry safety reporting with important boundaries. They describe recorded counts and terms in the specified group; they do not establish a comparative treatment effect, a complete causal account, or the precision of the primary endpoint. The registry record also does not report how the enrollment total relates to the safety analysis set.
13. Why This Trial Matters Statistically
This investigation is statistically relevant because it asks safety questions in a clinical-practice setting where treatment was received as prescribed by a physician. Its stated aims include identifying adverse drug reactions not previously known, describing the incidence and circumstances of reactions, and examining factors that may affect safety and effectiveness. These aims differ from estimating a randomized treatment contrast: they emphasize describing what is recorded among treated participants.
The distinction between enrollment and the analysis population matters. Enrollment is 403, while the safety summary lists 396 participants at risk. The primary outcome is assigned to a safety analysis set, but the record does not explain the population rules or the difference between these figures. Clear population definitions are essential because an event count has meaning only in relation to the participants included and the period over which outcomes are assessed.
The registry also illustrates why outcome definitions and reporting completeness matter. The primary endpoint counts participants with adverse drug reactions over 24 weeks, while the safety summary separates serious and other reactions. The primary endpoint’s numerical result is not reported in the registry record. Readers should therefore resist substituting the available subgroup counts for the primary result or treating them as an exhaustive account.
Finally, 7 outcome measures and 30 analyses make transparent reporting of analytic priorities and multiplicity procedures important. Those procedures are not reported in the registry record. The record’s warning that the arms are not a like-for-like control comparison is equally important: descriptive safety results and comparative efficacy claims answer different statistical questions. Recognizing these distinctions helps keep interpretation proportional to the evidence actually described.
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 primary limitation is that the numerical result for the primary endpoint is not reported in the registry record. Although the endpoint is defined as the number of participants with adverse drug reactions over 24 weeks, the safety summary instead gives counts for serious and other reaction groupings. Those summaries do not fill the primary result gap, and the record does not state whether participants could appear in both groupings.
The registry entries do not report a comparator group, and the record cautions that the arms are not a like-for-like control comparison. Allocation is not stated. As a result, there is no basis in the registry record for interpreting these safety counts as a comparative effect. Treatment details beyond physician-prescribed adalimumab, including dose and schedule, are not reported in the registry record.
Enrollment was 403, while 396 participants are listed at risk in the safety summary. The reasons for this difference, the inclusion rules for the safety analysis set, and the handling of incomplete follow-up are not reported in the registry record. This leaves uncertainty about how the analyzed group was formed and how missing observations may have affected the summaries.
Uncertainty estimates for the primary endpoint, including confidence intervals, are not reported in the registry record. Detailed analytic methods, adjustment for multiple analyses, and the handling of potential confounding factors are also not reported. The registry lists 7 outcome measures and 30 analyses, but does not describe the analysis hierarchy or which analyses were prespecified. These limitations restrict assessment of precision, multiplicity, and the robustness of any interpretation beyond the reported descriptive safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Special Investigation in Patients With Ankylosing Spondylitis (All Patients Investigation) — NCT01329380.
- Registry record last updated 2019-04-03; status last verified 2018-12.
- Results first posted 2019-04-03.
- 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 describes a completed special investigation of adalimumab (Humira) in participants with ankylosing spondylitis. Participants received treatment as prescribed by their physician. Enrollment was 403; the primary safety outcome concerns a safety analysis set over 24 weeks. The adverse event summary lists 396 participants at risk, 17 participants in the serious adverse reaction grouping, 113 in the other adverse reaction grouping, and 0 deaths.
The primary endpoint is the number of participants with adverse drug reactions, but its numerical result is not reported in the registry record. The record lists secondary improvement-rating and BASDAI outcomes, 7 outcome measures, and 30 analyses. Allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. Details about missing data, precision estimates, and multiplicity handling are not reported in the registry record.