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 A Study To Describe The Use Of Tofacitinib After Use Of Rituximab In Patients With Rheumatoid Arthritis In A Real-World Setting (NCT05487703), a registered phase not stated study. The primary outcome is Number of Participants According to Type of Health Insurance Plan.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05487703 |
| Phase | Phase not stated |
| Condition | Arthritis, Rheumatoid |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 318 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Adults with rheumatoid arthritis initiating tofacitinib after use of rituximab, in a real-world setting. The analysis population is described as eligible participants whose medical records were retrieved and observed. The registry reports enrollment of 318, but does not report how many participants contributed data to each outcome.
Intervention
Initiation of tofacitinib, defined in the primary-outcome description as first-ever use of tofacitinib. The study characterizes use after rituximab; it is not described as assigning treatment.
Comparator
No comparative control group is specified for the primary outcome. The record does not state an allocation method, and the study is not described as a randomized comparison.
Primary question
How many participants were recorded in each health insurance plan category at the index date? Categories were private, Medicare, Medicaid, and no insurance. The index date was the date of tofacitinib initiation at or after registry enrollment. The record notes that a participant might have more than one type of insurance.
The study is framed as a description of tofacitinib use after rituximab among people with rheumatoid arthritis, rather than as a test of a treatment against a comparator. Its primary outcome is descriptive: it counts participants according to insurance plan, not clinical improvement or a treatment effect. That distinction matters when interpreting the record. Insurance categories describe the population and its recorded coverage; by themselves, they do not establish why treatment was initiated or what happened after initiation.
The registry also lists secondary outcomes concerning minimum clinically important difference (MCID), change in Health Assessment Questionnaire (HAQ), pain visual analogue scale (VAS), and fatigue VAS at 6-month follow-up. Outcome values for these measures are not reported in the registry record. Thus, the stated clinical question includes follow-up measures, but the posted results do not allow their direction, magnitude, or precision to be described.
3. Trial Design
This is a real-world, retrospective study intended to characterize tofacitinib use in rheumatoid arthritis after rituximab. The record describes an analysis of medical records retrieved for eligible participants. Enrollment is reported as 318, while the analysis population is defined as eligible participants whose records were retrieved and observed. The number contributing to each reported outcome is not reported in the registry record.
The record identifies a clinical-characteristics group for adult patients with rheumatoid arthritis initiating tofacitinib. It does not describe random assignment, and allocation is not stated. No like-for-like control comparison is specified. Accordingly, the study design supports a descriptive account of recorded characteristics and outcomes, rather than a direct randomized estimate comparing treatment strategies.
The primary outcome is the number of participants according to health insurance plan at the index date. The index date was defined as tofacitinib initiation at or after enrollment in the registry, with initiation defined as first-ever use. The index date could fall during the observation period from 06-Nov-2012 to 31-Oct-2022, described as approximately 9 years. The record says the data were observed retrospectively from 14-Nov-2022 to 23-Dec-2022, for approximately 1 month. These are different time windows: the broad period in which index dates could occur and the shorter period of retrospective study observation.
The record lists 32 outcome measures and identifies secondary measures at 6-month follow-up. It does not report the statistical analysis methods, a prespecified statistical analysis plan, or analyses for those outcomes. The registry status is COMPLETED. Completion describes the study’s recorded status, not whether every planned measure has a posted result or whether the available information answers a causal 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.
Before assignment: Total 3190 participants were screened, out of which 2872 participants did not met the inclusion criteria and only 318 participants were included in the study.
Overall Study
| Stage | Tofacitinib |
|---|---|
| STARTED | 318 |
| Subset With 6 Month Visit | 232 |
| COMPLETED | 209 |
| NOT COMPLETED | 109 |
Reasons for not completing this period:
| Reason | Tofacitinib |
|---|---|
| Other | 19 |
| Participant not well | 5 |
| Insurance Reasons | 6 |
| Physician Decision | 19 |
| Lack of Efficacy | 60 |
Analysis population for the primary outcome, as defined in the registry: Analysis population included all eligible participants whose medical records were retrieved and observed in this 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.
Population: Analysis population included all eligible participants whose data were observed in this study.
| Characteristic | Unit | Tofacitinib |
|---|---|---|
| Participants analysed | 318 | |
| Age, Continuous | Years | 59.9 (SD 11.8) |
| Sex: Female, Male: Female | Participants | 262 |
| Sex: Female, Male: Male | Participants | 56 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 277 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 37 |
| Body Weight | Kilograms | 86.0 (SD 22.3) |
| Body Mass Index (BMI) Categorical: BMI (kg/m^2) <25 | Participants | 71 |
| Body Mass Index (BMI) Categorical: BMI (kg/m^2) 25.0 to <30 | Participants | 74 |
| Body Mass Index (BMI) Categorical: BMI (kg/m^2) >=30 | Participants | 169 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants According to Type of Health Insurance Plan, measured over At index date, index date could be anytime during observation period from 06-Nov-2012 to 31-Oct-2022, approximately 9 years (data was observed retrospectively in this study from 14-Nov-2022 to 23-Dec-2022, for approximately 1 month).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants according to health insurance plan at the index date. The listed categories are private, Medicare, Medicaid, and no insurance. The index date is tied to tofacitinib initiation at or after registry enrollment, with initiation defined as first-ever use. The registry notes that an individual may have more than one insurance type, so the categories should not automatically be interpreted as mutually exclusive.
This endpoint is used to describe the recorded population and its coverage context. A count by insurance category can help readers understand who is represented in the study records, but it is not a clinical outcome and does not measure symptom change, disease activity, or treatment response. It also does not establish that insurance status caused or influenced treatment decisions. Those questions would require relevant variables and analyses that are not reported in the registry record.
No category counts, percentages, or uncertainty estimates for this endpoint are reported in the registry record. Consequently, the distribution of insurance types cannot be described from the posted results. The outcome title specifies what was to be measured, while the absence of numerical results prevents an assessment of the observed distribution or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a descriptive primary outcome: counts of participants across health insurance plan categories at the index date. However, it does not report the counts for private insurance, Medicare, Medicaid, or no insurance. No estimate of the distribution, and no measure of its statistical precision, is therefore available from the posted results. The endpoint can be described conceptually, but its observed values cannot be interpreted.
The registry lists 318 participants as the enrollment figure. That figure should not be treated as the denominator for every outcome: the analysis population is described as eligible participants whose records were retrieved and observed, and the number contributing to each outcome is not reported in the registry record. Because a participant may have more than one type of insurance, category counts also need not represent mutually exclusive groups. Without the outcome counts and denominators, the extent of overlap or missing information cannot be assessed.
Four secondary outcome types are named: the percentage achieving MCID at 6-month follow-up and changes from baseline in HAQ, pain VAS, and fatigue VAS at 6 months. Their numerical results, analysis populations, and uncertainty measures are not reported in the registry record. The record therefore does not support conclusions about the amount or direction of change, the proportion achieving MCID, or how precisely any such quantity was estimated.
The registry reports 32 outcome measures and 0 analyses. The absence of posted analyses means that statistical tests, model-based estimates, confidence intervals, and adjusted comparisons are not available for interpretation. The fact that the study is marked COMPLETED does not fill that gap. Completion status is not itself evidence of a particular outcome or of a sufficiently precise estimate.
As a general statistical point, descriptive counts answer questions about what was recorded in a particular study population. They do not, without a suitable comparison and analysis, estimate what would have happened under another treatment or establish a causal effect. This distinction is especially important in a real-world record without a stated randomized allocation or specified control comparison. Here, the posted information gives the study purpose and endpoint definitions, but not numerical endpoint results from which to judge the observed patterns.
9. Statistical Methods Explained
The registry record does not report the statistical analysis methods used for the outcomes. The explanations below are general descriptions of the statistical ideas relevant to the stated measures; they should not be read as claims about methods used in this study.
What does a descriptive count tell the reader?
A count states how many recorded observations fall into a category. For this study, the primary measure is the number of participants according to health insurance plan. Counts are useful for describing the composition of the records, but interpretation depends on knowing the analysis denominator and how categories were assigned. The registry says that a participant might have more than one insurance type. If categories overlap, adding their counts would not necessarily produce the number of participants. No such addition is needed to interpret the endpoint, and the category counts themselves are not reported.
Counts can be accompanied by percentages to express category frequency relative to a clearly defined denominator. A percentage is interpretable only when its numerator, denominator, and handling of missing or overlapping categories are clear. The registry record does not report category percentages, outcome-specific denominators, or how missing insurance information was handled. As a result, neither the count distribution nor a percentage distribution can be reconstructed.
What would an estimate of change require?
The secondary outcomes include changes from baseline in HAQ, pain VAS, and fatigue VAS at 6-month follow-up. In general, a change estimate compares a participant’s follow-up measurement with a baseline measurement, then summarizes those changes across the analysis population. The estimate’s meaning depends on the scale, the definition of baseline, which follow-up observations are included, and how incomplete pairs are treated. The registry record names the measures and follow-up timing, but does not report the numerical changes, their variability, or the analysis details needed to interpret them.
MCID is a threshold concept: it identifies a change considered minimally important under a specified definition. A reported percentage achieving MCID would depend on the threshold, the direction and calculation of change, and the denominator used. Those details and the observed percentage are not reported in the registry record. Naming MCID as an outcome does not by itself establish which threshold was applied or how many participants met it.
How should precision be assessed?
In general, a confidence interval describes the uncertainty around an estimate under the statistical model used to calculate it. A narrow interval indicates greater precision than a wide interval, while the interval’s location describes values compatible with the data and model. A confidence interval is not a guarantee that the true value lies within its limits, and it does not correct problems such as selection bias, missing data, or an unsuitable comparison. No confidence intervals are reported for the primary or secondary outcomes, so the precision of those outcomes cannot be assessed.
Variation among observations also matters. For a count or proportion, precision depends on the number of observations and the relevant denominator. For a change measure, it depends on the distribution of individual changes and the number with usable baseline and follow-up data. The overall enrollment figure of 318 does not establish the denominator for any particular outcome. Outcome-specific sample sizes are not reported in the registry record.
What is the role of a comparison?
In general, a comparison can help distinguish an outcome pattern associated with one group from the pattern in another, but the groups must be interpretable for the question being asked. Random assignment is one design feature that can support a causal comparison by reducing systematic differences between groups, though it does not guarantee that all other design and analysis concerns are resolved. This record does not describe a randomized comparison, allocation is not stated, and no like-for-like control comparison is specified. The primary endpoint is descriptive, so a treatment contrast is not available for it.
Statistical adjustment can sometimes account for measured differences between groups, but it cannot necessarily address unmeasured differences. The registry record does not report adjusted models, covariates, or comparative effect estimates. It would therefore be inappropriate to infer that adjustment was performed or to interpret this study as establishing a causal treatment effect.
What can planning calculations show?
In general, sample-size planning calculations describe the amount of information a future study might need to detect a chosen effect under stated assumptions. They are planning illustrations, not observed power and not evidence that an effect occurred. The record describes planning assumptions involving 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. It also distinguishes planning for events in time-to-event settings from planning participants per arm for other settings. Those assumptions do not establish that this observational study used such an allocation or analysis. Numerical planning outputs are not reported in the registry record, and no observed effect is available in the registry entries from which to characterize the illustrations.
Over-dispersion is a general issue when count variability exceeds what a simple model assumes. If present, a model that ignores it may understate uncertainty and produce intervals that are too narrow. The registry does not report a count model, a dispersion estimate, or evidence of over-dispersion for this endpoint. This concept is relevant as a general modeling consideration, but it cannot be attributed to the analysis in this study.
Finally, the number of listed outcomes can make interpretation more complex if many statistical tests are performed. A multiplicity strategy may be used in some studies to manage the risk of chance findings across multiple tests. The registry record does not report tests, a multiplicity approach, or an analysis plan. Therefore, no claim can be made about whether such a strategy was used.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 32 outcome measures, including the primary insurance-plan count and secondary measures related to MCID, HAQ, pain VAS, and fatigue VAS at 6-month follow-up. It reports 0 analyses. The statistical analysis plan, any prespecified hierarchy among outcomes, and any method for addressing multiple comparisons are not reported in the registry record. Because no statistical tests or numerical results are posted, it is not possible to assess how multiplicity affected the interpretation of findings.
Missing data are also important for outcomes requiring records at more than one time point. In general, a change from baseline requires usable baseline and follow-up information, while a percentage achieving MCID requires both a defined threshold and an appropriate denominator. The registry record does not report the number with observed follow-up, the amount or pattern of missingness, or the method used to handle missing measurements. It therefore does not show whether the follow-up results represent all eligible participants, only those with available measurements, or another analysis population.
The primary-outcome population is described as eligible participants whose medical records were retrieved and observed. The registry does not report outcome-specific population counts or explain whether records could be excluded for incomplete insurance information. Enrollment of 318 is not, by itself, an outcome denominator. Since participants might have more than one insurance type, category overlap and missingness would also need to be clarified to interpret category frequencies.
These omissions limit assessment of both representativeness and precision. They do not prove that data were missing or that an analysis was biased; the amount and handling of missing data are simply not reported in the registry record. Likewise, no conclusion can be drawn about whether multiplicity adjustments were necessary or applied.
11. What the Result Does, and Does Not, Mean
The record establishes that the study was intended to characterize tofacitinib use after rituximab among people with rheumatoid arthritis in a real-world setting. It specifies a primary descriptive measure based on insurance plan at the index date and names several clinical follow-up outcomes. These definitions clarify what the investigators intended to describe, but they do not provide the numerical results needed to characterize what was observed.
The registry reports enrollment of 318 and marks the study COMPLETED. Neither item supplies outcome values. The analysis population is described as eligible participants with medical records retrieved and observed, but outcome-specific denominators are not reported. The 6-month follow-up measures are listed without their estimates, and the primary insurance-category counts are also absent. Thus, the posted information cannot show the distribution of insurance types, the proportion achieving MCID, or the amount of change in HAQ, pain VAS, or fatigue VAS.
In general, descriptive findings can help characterize a study population and guide questions for further research. They do not automatically show that a treatment caused an outcome. Here, no randomized comparison or like-for-like control group is specified, and no comparative statistical analysis is reported. The record therefore does not support a causal interpretation or a conclusion about relative treatment effects.
The registry’s adverse-event entries list 0 for the recorded at-risk and affected counts and deaths in each of the two listed groups. These entries should be read narrowly as the values recorded in those fields. They do not provide event descriptions or a statistical analysis, and they cannot establish a broader safety conclusion. The absence of reported serious-event terms likewise does not resolve whether events were assessed, how follow-up was defined, or how complete the records were; those details are not reported in the registry record.
Overall, the record supports an account of the study’s purpose, population definition, index-date framework, and intended outcomes. It does not provide enough numerical or methodological detail to quantify the observed outcomes, assess their precision, or infer a treatment effect.
12. Why This Trial Matters Statistically
This study is statistically informative as an example of the difference between an outcome definition and an outcome result. The registry clearly names a primary measure—participants according to health insurance plan at the index date—and describes the categories and index-date rule. Yet no category counts are reported. Without the values and the relevant denominators, the endpoint cannot answer even its immediate descriptive question about the recorded distribution.
The record also distinguishes a broad period in which index dates could occur, from 06-Nov-2012 to 31-Oct-2022, from the retrospective observation period, 14-Nov-2022 to 23-Dec-2022. Keeping these windows conceptually separate helps readers understand that the index date could be well before the period in which records were retrospectively reviewed. The registry describes the broader interval as approximately 9 years and the retrospective period as approximately 1 month.
For clinical researchers, the listed 6-month measures illustrate why outcome definitions alone are not enough for interpretation. Estimates need analysis populations, follow-up completeness, methods for handling missing measurements, and uncertainty measures. None of these outcome results or analysis details is reported in the registry record. Enrollment of 318 cannot substitute for outcome-specific denominators or precision estimates.
More broadly, a real-world descriptive study can address questions about recorded clinical practice and population characteristics, but its design does not automatically provide a causal comparison. Allocation is not stated, and no like-for-like control comparison is specified. Recognizing that boundary prevents descriptive information from being interpreted as proof of a treatment effect. In this record, the primary value is the specification of the intended characterization; the posted results do not permit quantitative conclusions about that characterization.
13. 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.
A central limitation is that the registry record does not report numerical results for the primary outcome. Although it defines insurance categories and the index date, no category counts, percentages, or precision estimates are available. The possible overlap between insurance categories further means that category totals cannot be assumed to correspond to a participant total.
The registry reports enrollment of 318, but does not report the number of records contributing to the primary endpoint or to each secondary measure. The described analysis population consists of eligible participants whose medical records were retrieved and observed. The relationship between enrollment and each outcome-specific analysis population is therefore unclear. Missingness, exclusions, and follow-up completeness are not reported in the registry record.
The secondary outcomes are named, but their estimates and analysis methods are not reported. This prevents assessment of the 6-month MCID measure and changes in HAQ, pain VAS, and fatigue VAS. The registry also does not report outcome-specific uncertainty, statistical tests, adjusted analyses, or an analysis plan. The record lists 32 outcome measures and 0 analyses, leaving no posted inferential results to evaluate.
The study is described as real-world and retrospective, and no randomized comparison or like-for-like control is specified. Allocation is not stated. These features limit the kinds of comparisons that can be interpreted from the record; in particular, no causal treatment contrast is reported. The timing information also includes a long period during which an index date could occur and a shorter retrospective observation period, but details of data capture and changes in practice across that interval are not reported.
Finally, adverse-event entries show zero in the listed fields, but the record does not provide enough context to determine the completeness or scope of adverse-event ascertainment. These entries should not be taken as a comprehensive safety analysis.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: A Study To Describe The Use Of Tofacitinib After Use Of Rituximab In Patients With Rheumatoid Arthritis In A Real-World Setting — NCT05487703.
- Registry record last updated 2024-10-08; status last verified 2024-07.
- Results first posted 2024-10-08.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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17. Record Summary
The registry record for NCT05487703 describes a completed, retrospective real-world study of tofacitinib use after rituximab in rheumatoid arthritis. Enrollment is reported as 318. The primary outcome is the number of participants by health insurance plan at the index date; a participant may have more than one type of insurance. Index dates could occur from 06-Nov-2012 to 31-Oct-2022, while retrospective observation is described as running from 14-Nov-2022 to 23-Dec-2022.
Secondary outcomes include MCID achievement and changes in HAQ, pain VAS, and fatigue VAS at 6-month follow-up. The registry lists 32 outcome measures and 0 analyses. Numerical outcome results, outcome-specific denominators, missing-data methods, and statistical analysis methods are not reported in the registry record. The posted information defines the study questions but does not permit quantitative interpretation of the primary or secondary outcomes.