Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in China: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in China (NCT02668640), a registered phase not stated study. The primary outcome is Median Change From Baseline in Health Assessment Questionnaire- Disability Index (HAQ-DI) Score at Week 24.

2. Clinical Question

3. Trial Design

The ROCKI Study is a real-world study of adalimumab in participants with rheumatoid arthritis in China. The registry lists the study as completed, with a start date of 2016-05-01 and a primary completion date of 2018-06-12. Enrollment is recorded as 55. The registry describes one treatment group: participants with rheumatoid arthritis receiving adalimumab. The regimen was 40 mg by subcutaneous injection every other week for 24 weeks.

This was not a randomized comparison. Allocation is not stated, and the registry record does not describe a control arm that could serve as a like-for-like comparator. As a result, the design is suited to describing outcomes among participants receiving treatment, but it does not by itself separate changes during follow-up from changes that might have occurred for other reasons. It also does not support a direct comparison with another treatment based on the information reported in the registry.

The primary outcome was median change from baseline in HAQ-DI score at Week 24. The primary analysis population is described as participants who continued adalimumab after the baseline visit and had available data. The registry record does not report the number in this population, the number with a Week 24 measurement, or how participants without available data were handled.

Secondary outcomes include HAQ-DI, SF-36 physical and mental component scores, EQ-5D-3L, work productivity and activity impairment, and clinically meaningful HAQ-DI improvement. The record lists 8 outcome measures and 12 analyses. It does not report a statistical analysis plan, a sample-size justification for the trial, or details of any interim analyses. A sample-size justification is 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.

Before assignment: All participants who received at least one dose of adalimumab during the study

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Observed population: participants continuing adalimumab treatment after the baseline visit; participants with available data

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: All participants who received at least one dose of adalimumab during the study

6. Primary Endpoint

The registry lists the primary outcome as Median Change From Baseline in Health Assessment Questionnaire- Disability Index (HAQ-DI) Score at Week 24, measured over Baseline and Week 24.

The primary endpoint is median change from baseline in the Health Assessment Questionnaire–Disability Index score at Week 24. HAQ-DI is a participant-reported questionnaire specific to rheumatoid arthritis. Its 20 questions cover dressing and grooming, arising, eating, walking, hygiene, reach, grip, and daily activities. Participants report their ability to perform each task over the past week using categories from without difficulty to unable to do.

Task scores are summed and averaged to give an overall score from 0 to 3. A score of zero represents no disability, while three represents very severe, high-dependency disability. The endpoint uses the change from baseline to focus on how participants’ reported functional disability shifted during follow-up, rather than only describing their status at a single visit. The median describes the middle of the observed change values and is less affected than the mean by particularly large or small values. The inter-quartile range describes the spread of the middle half of those values. A negative median change indicates improvement from baseline according to the registry record.

HAQ-DI is relevant to the stated study objective because it captures reported difficulty with everyday activities. However, the numerical median change and inter-quartile range are not reported in the registry record. The endpoint’s direction and measurement are described, but the magnitude and variability of the observed result cannot be assessed from the posted registry information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a median change describe?

The primary measure is the median change in HAQ-DI score between baseline and Week 24. For each participant with the relevant data, change represents the follow-up score in relation to the baseline score. The median is the middle value when observed changes are ordered. It describes a typical position in the distribution without requiring that unusually large changes have the same influence they would have on an arithmetic average. The registry record specifies that a negative median indicates improvement from baseline.

The median alone does not describe every participant’s experience. Participants may have changes that differ substantially from the median, and the median does not show how many improved, remained stable, or worsened. The registry identifies the inter-quartile range as the measure of dispersion for the primary endpoint. In general, an inter-quartile range describes the span between the lower and upper quartiles and conveys the spread of the middle portion of observed values. The numerical median and inter-quartile range are not reported in the registry record.

How is HAQ-DI interpreted?

HAQ-DI is a participant-reported measure specific to rheumatoid arthritis. Its 20 tasks cover eight domains: dressing and grooming, arising, eating, walking, hygiene, reach, grip, and daily activities. Participants rate their ability over the past week using response categories of without any difficulty, with some difficulty, with much difficulty, and unable to do. Scores are summed and averaged into an overall value ranging from 0 to 3. Zero represents no disability and three represents very severe, high-dependency disability.

Because the measure is participant-reported, it captures perceived difficulty with daily tasks rather than an observer’s direct assessment of performance. Its interpretation depends on the score definition, the timing of assessment, and the participants whose responses are available. A change score describes movement relative to baseline; it is not the same as the absolute score at Week 24. The registry record does not report the baseline or Week 24 median scores in the information.

What does uncertainty mean for a result?

In general, an estimate from a sample is subject to uncertainty because another sample of participants might produce a different estimate. A confidence interval is one common way to express that uncertainty around an estimated effect. Its width reflects precision under the assumptions used to calculate it; narrower intervals generally indicate more precise estimates, while wider intervals indicate greater uncertainty. No confidence interval for the primary outcome is reported in the registry record.

A significance test addresses a different question. In general, a p-value describes how compatible the observed data are with a specified null hypothesis, subject to the test’s assumptions. It does not measure the size or practical importance of an effect, and it does not establish causation. The registry record does not report a p-value or the statistical test for the primary outcome. Neither statistical significance nor a lack of statistical significance can therefore be inferred.

Why does the design matter?

The registry describes a single treatment group and states that this was not a randomized comparison. Randomization, when used, is intended to make treatment groups comparable on average with respect to measured and unmeasured factors. There is no randomized comparator. Consequently, a change from baseline in the treatment group is descriptive: it records what happened among the observed participants over follow-up, but does not show what would have happened to those same participants under a different treatment or without treatment.

This distinction applies even if a change is numerically large or appears consistent with improvement. A before-and-after contrast can be influenced by factors other than the intervention, and the registry record does not provide a comparison that would separate those influences. The treatment regimen is described as 40 mg by subcutaneous injection every other week for 24 weeks, but the record does not report adherence or exposure details beyond that regimen.

How should planning illustrations be read?

In general, a sample-size calculation is a planning exercise based on assumptions about a target effect, variability, significance level, allocation, and analysis method. The registry record’s described illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it considers fractions of an observed effect. These are planning assumptions, not evidence that the study was designed with those assumptions. The illustration is not the trial’s own design justification, and any sample sizes calculated under it are not observed power. The trial’s own sample-size justification is not reported in the registry record.

Over-dispersion, in general, means that observed variability is greater than a statistical model expects. When it is present, standard errors based on an under-dispersed model can be too small, making uncertainty appear less than it is. The registry information does not identify a count-model analysis or report an over-dispersion assessment, so no such issue can be attributed to the primary HAQ-DI analysis.

The record lists 8 outcome measures and 12 analyses. When investigators examine multiple outcomes or analyses, the chance of at least one apparently unusual result can increase if each is interpreted separately without adjustment. A multiplicity plan can define how results are prioritized or how statistical error is controlled. The registry record does not report whether such a plan was used. The outcome list alone does not establish that every result was a confirmatory test.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 8 outcome measures and 12 analyses. Alongside the primary HAQ-DI change at Week 24, secondary outcomes include HAQ-DI at Week 12, SF-36 physical and mental component scores at Weeks 12 and 24, EQ-5D-3L index, work impairment, activity impairment, and clinically meaningful HAQ-DI improvement. Considering several outcomes and analysis occasions can create multiplicity: in general, examining many results can increase the chance of observing an apparently notable result by chance. The statistical analysis plan and any multiplicity adjustment are not reported in the registry record, so the hierarchy and confirmatory status of the analyses cannot be assessed.

The primary outcome population includes participants continuing adalimumab after baseline who had available data. This is an observed-data definition, but the registry record does not state how many participants were included in that analysis or how missing values were handled. It does not report the number with measurements at each follow-up, reasons for missing data, or whether any imputation or sensitivity analyses were used. Without those details, it is not possible to judge how missingness may have affected the estimate or how representative the analyzed population was of all enrolled participants.

The record also does not describe whether participants were analyzed according to treatment initiation, continued exposure, or another analysis population definition beyond the primary outcome description. The full statistical analysis plan and details of interim analyses are not reported in the registry record. These gaps limit assessment of prespecification, data completeness, and the robustness of any outcome interpretation.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: rheumatoid arthritis (1.8%), bronchitis (1.8%).

The registry safety group records 55 participants at risk for serious adverse events and 2 participants affected. It records 55 participants at risk for other adverse events and 17 participants affected. Deaths are recorded as 0. The listed serious adverse event terms are rheumatoid arthritis and bronchitis, each shown as 1.8%.

These counts describe events recorded in the treatment group. They do not provide a comparison with a control group, and the registry information does not establish that an event was caused by adalimumab. The serious-event term list gives the recorded terms and percentages, but does not provide further clinical detail about timing, severity beyond the serious classification, outcome, or relationship to treatment. Those details are not reported in the registry record.

Counts should also be distinguished from event rates over person-time: the record gives participants at risk and participants affected, but does not report person-time or an exposure-adjusted rate. The figures do not describe the safety experience of participants who may not have continued or had complete follow-up unless they are included in the recorded safety group. The registry record does not provide a comparator or further information needed to assess differences in safety between groups.

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

The registry record describes a real-world study of adalimumab in participants with rheumatoid arthritis in China, with a primary focus on median change in HAQ-DI score from baseline to Week 24. It defines the scale, the observed population, and the direction of change: a negative median indicates improvement from baseline. It also records enrollment of 55 and a treatment regimen of 40 mg by subcutaneous injection every other week for 24 weeks.

However, the numerical primary outcome estimate and inter-quartile range are not reported in the registry record. The posted information therefore does not show the amount of change or its spread. It also does not report a confidence interval or p-value for the primary outcome. Without those statistics, the precision and statistical evidence for the primary result cannot be assessed. Listing secondary outcomes does not reveal their results; their numerical findings are not reported in the registry information.

The study is not a randomized comparison, and no like-for-like control arm is described. A change observed over time in the treatment group cannot, on its own, establish that treatment caused the change. It does not show how the same participants would have fared under a different treatment or without treatment. This is a limitation of the design’s comparative interpretation, rather than a statement about the direction or size of any unreported outcome.

The primary analysis population consists of participants who continued treatment after baseline and had available data. The number meeting that definition and the handling of missing outcome data are not reported in the registry record. As a result, the extent to which the analyzed group represents all enrolled participants cannot be assessed. The safety counts describe recorded participants and events but do not establish causation or comparative risk.

Accordingly, the record supports a description of the study question, regimen, outcome definitions, and recorded safety counts. It does not support a conclusion about the magnitude, precision, or causal meaning of the primary outcome. It also does not establish treatment benefit or lack of benefit.

13. Why This Trial Matters Statistically

This study illustrates why a registered outcome definition and a numerical result are not interchangeable. The registry describes HAQ-DI, its scale, the direction of change, and the Week 24 assessment. Those details help readers understand what the endpoint was intended to measure. But the numerical median change and inter-quartile range are not reported in the registry record, so the main descriptive result cannot be quantified from the posted information.

It also highlights the statistical distinction between observing change and estimating a treatment effect. A single-group before-and-after result, even when reported, describes change among observed participants. Without a like-for-like comparator, it does not isolate the effect of treatment from other influences. That distinction is especially important in a real-world study, where the registry’s treatment group is not described as randomized and allocation is not stated.

The analysis population matters as well. The primary outcome is based on participants who continued treatment after baseline and had available data, rather than an explicitly reported total of all enrolled participants. The number analyzed and the approach to missing data are not reported. Readers therefore cannot evaluate data completeness or the potential influence of selection into the observed population.

Finally, the registry lists multiple outcome measures and analyses. Without a reported statistical plan or multiplicity approach, readers cannot determine how the outcomes were prioritized or how findings across analyses should be interpreted together. These are not reasons to discard the study description; they are boundaries on what can be inferred from the registry record. Clear distinctions between endpoint definition, numerical result, uncertainty, analysis population, and comparison design are central to responsible statistical interpretation.

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 principal limitation for interpreting the primary endpoint is that its numerical median change and inter-quartile range are not reported in the registry record. The record therefore does not allow readers to characterize the magnitude or dispersion of the Week 24 change. A confidence interval, p-value, and statistical test for the primary outcome are also not reported.

The design is not a randomized comparison, and a like-for-like control group is not described. The registry states that allocation is not stated. Consequently, even a reported baseline-to-follow-up change would be descriptive rather than a direct estimate of the contrast between adalimumab and another treatment or no treatment.

The primary outcome population is restricted to participants continuing treatment after baseline who had available data. The number of participants in that population, the number with Week 24 data, the reasons for unavailable measurements, and the missing-data methods are not reported in the registry record. This limits assessment of attrition, representativeness, and possible bias from missing data.

Although the record lists 8 outcome measures and 12 analyses, their numerical results are not reported in the information. The statistical analysis plan, multiplicity approach, and details of interim analyses are not reported. The trial’s own sample-size justification is also not reported, so the planning illustration described in the statistical methods should not be mistaken for the study’s design rationale or observed power.

The safety information reports counts and selected serious adverse event terms, but not a comparator, person-time, detailed event histories, or treatment relatedness. These limitations restrict comparative and causal safety interpretation. The registry record does not provide enough information to resolve these gaps.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in China — NCT02668640.
• Registry record last updated 2019-09-13; status last verified 2019-08.
• Results first posted 2019-09-13.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record identifies NCT02668640, titled “Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in China,” also called the ROCKI Study. It is marked completed and lists enrollment of 55. The recorded study dates are 2016-05-01 for study start and 2018-06-12 for primary completion. AbbVie is listed as sponsor.

Participants with rheumatoid arthritis received adalimumab 40 mg by subcutaneous injection every other week for 24 weeks. The primary outcome was median change from baseline in HAQ-DI score at Week 24 among participants continuing treatment after baseline who had available data. The numerical primary result and inter-quartile range are not reported in the registry record. The study was not a randomized comparison, and allocation is not stated.

The record lists secondary outcomes spanning health status, quality of life, work and activity impairment, and clinically meaningful HAQ-DI improvement. Safety records include 2 participants with serious adverse events, 17 with other adverse events, and 0 deaths among 55 at risk. The listed serious-event terms are rheumatoid arthritis and bronchitis, each at 1.8%.