Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in Taiwan: 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 Taiwan (NCT02616380), a registered phase not stated study. The primary outcome is Change From Baseline in Health Assessment Questionnaire Disability Index (HAQ-DI) Score at Week 24.

2. Clinical Question

The study was designed to assess health-related quality of life and work productivity in people with rheumatoid arthritis receiving adalimumab in Taiwan. Its primary outcome focuses on physical function, measured with the Health Assessment Questionnaire Disability Index (HAQ-DI). The endpoint is a change over time within the specified participant group, rather than a comparison between treatment groups.

That distinction matters when interpreting the question. In an observational study without a described control group, a change between baseline and follow-up describes how scores differed over time among the analyzed participants. By itself, it does not isolate the effect of adalimumab from other influences, such as the course of the condition or changes in care. The numeric change, its variability, and any uncertainty interval are not reported in the registry record, so the direction and precision of the primary result cannot be characterized from the record.

3. Trial Design

This was a prospective, observational study of adalimumab among people with rheumatoid arthritis in Taiwan. The stated purpose was to assess effects on health-related quality of life and work productivity. The registry records an enrollment of 100 and lists the study as completed. The recorded start date is 2015-11-05, and the primary completion date is 2017-11-23.

Adalimumab was prescribed at the physician’s discretion in routine clinical practice. The record describes one adalimumab group and does not state an allocation procedure. It does not describe a randomized comparison, and there is no like-for-like control group in the listed design. Accordingly, the main endpoint is framed as change from baseline within the defined group, not as a contrast between adalimumab and another treatment or a control condition.

The primary endpoint was change from baseline in HAQ-DI score at Week 24. The primary population was restricted to participants who were still receiving adalimumab at Week 24 and had HAQ-DI measurements at baseline and Week 24. That restriction is important: the endpoint does not, on its face, represent everyone enrolled. The number meeting those criteria is not reported in the registry record.

Listed secondary outcomes include SF-36 physical and mental component scores, EQ-5D-3L index, work productivity and activity impairment, HAQ-DI at Week 12, clinically meaningful HAQ-DI improvement, and healthcare resource use. These outcomes cover quality of life, function, work, and service use. The registry lists 10 outcome measures and 12 analyses. Numeric results for those outcomes are not reported in the registry record.

The record does not report a sample-size justification, a statistical analysis plan, interim analyses, or a detailed account of how confounding was handled. Those omissions limit what can be concluded about the design’s ability to answer causal questions or how the analyses were specified in advance.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who were still receiving adalimumab at week 24 and with available HAQ-DI data at baseline and week 24.

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.

6. Primary Endpoint

The registry lists the primary outcome as 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 change from baseline in the Health Assessment Questionnaire Disability Index (HAQ-DI) score at Week 24. HAQ-DI is a patient-reported measure of physical function. It covers 20 items across eight categories of functional activities: dressing and grooming, arising, eating, walking, hygiene, reach, grip, and common daily activities. Participants report their ability to complete the tasks over the past week.

Each task is rated from 0, meaning without any difficulty, to 3, meaning unable to do the task. Scores are summed and averaged to create an overall score from 0 to 3. A higher score represents greater disability and dependency; 0 represents the best score and 3 the worst. A change score expresses how the measured score differed between baseline and Week 24. The registry specifies the mean and standard deviation as the summary measures.

Physical function is a relevant dimension of health-related quality of life because the instrument asks about everyday activities rather than only clinical signs. Repeated measurement can describe whether reported ability changed over the follow-up period. However, a within-participant change does not by itself identify why a score changed. In an observational study without a described control group, changes can reflect multiple influences, not just treatment exposure.

The analysis population was participants still receiving adalimumab at Week 24 with available HAQ-DI data at both time points. The numeric mean change and standard deviation are not reported in the registry record. Therefore, the size, direction, and precision of the primary endpoint cannot be stated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change describe?

The primary outcome is continuous: HAQ-DI is recorded on a numeric scale, and the registry specifies a mean as the summary measure. In general, a mean change is obtained by considering each participant’s follow-up score relative to that participant’s baseline score, then summarizing those changes across the analysis population. It describes the average direction and size of change in the group. The registry record does not report the resulting mean change, so its direction and magnitude cannot be described.

The mean alone does not show whether participant changes were similar or widely spread. The specified standard deviation describes variation in the observations around their mean. It is not the same as the uncertainty around the mean. A confidence interval, when reported, is generally used to express uncertainty in an estimated quantity under a stated statistical method. No numeric standard deviation or confidence interval for the primary outcome is reported in the registry record.

What does the scale mean?

HAQ-DI captures reported difficulty with functional activities. Its items are rated from 0 for no difficulty to 3 for inability to perform the task, and the overall score ranges from 0 to 3. Higher scores indicate greater disability. Thus, the direction of a change can be interpreted using the scale’s ordering, but the record does not provide the primary change estimate needed to make that interpretation for this study.

A change score and a follow-up score answer different descriptive questions. A follow-up score gives the level recorded at the follow-up assessment; a change score expresses how that level compares with baseline. The registry names change from baseline as the primary endpoint. Baseline and Week 24 are the stated measurement times, but their numeric summary values are not reported in the registry record.

What can an observational before-and-after analysis establish?

In general, repeated measurements can describe the course of a measure among participants observed over time. They do not, on their own, establish what would have happened to those same participants without the treatment. Here, prescribing was at physician discretion in routine practice, and a like-for-like control group is not described. This leaves potential alternative explanations for a change, including differences in participant characteristics, the natural course of illness, and other care. The registry record does not report methods for adjusting for confounding.

The analysis population also matters. The primary endpoint includes participants still receiving adalimumab at Week 24 with measurements at baseline and Week 24. Conditioning on continued treatment and available data can make that group different from everyone enrolled. The record does not state how many participants met these criteria or describe analyses of participants who stopped treatment or lacked measurements.

How should the planning assumptions be read?

The described planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a stated fraction of an observed effect. These are planning assumptions, not evidence that this observational study used a two-arm randomized design. The study record describes an adalimumab group and does not describe a like-for-like control group. Any resulting sample-size values are planning illustrations, not observed power and not proof that the completed study had a particular probability of detecting an effect.

In general, sample-size planning depends on assumptions about the effect to detect, variability, analysis, and design. If those assumptions differ from the actual study or population, the illustration may not describe the study’s operating characteristics. The trial’s own sample-size justification is not reported in the registry record. The stated planning assumptions cannot fill that gap.

Why does multiplicity matter?

The registry lists a primary endpoint alongside multiple secondary outcomes and analyses. In general, testing multiple outcomes can increase the chance of at least one apparently notable result when all are interpreted without accounting for multiplicity. A prespecified approach may distinguish a primary question from supportive or exploratory outcomes, or use an adjustment strategy. The registry record does not report a multiplicity strategy or enough numeric outcome results to assess how multiple findings were handled. The number of listed outcomes alone does not reveal whether any adjustment was performed.

What does a standard deviation not tell the reader?

In general, a standard deviation is about dispersion among observations, not the precision of a group mean and not the clinical importance of a change. A small or large standard deviation cannot be interpreted in isolation from the scale, the estimate, the analysis population, and the study design. For this study, the primary standard deviation is not reported in the registry record, so no judgment about the observed spread is possible.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Adalimumab")
n   <- c(94)
m   <- c(-0.44)
sp  <- c(0.59)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Adalimumab  94  -0.440  0.590  -0.561  -0.319

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 12 analyses. A primary HAQ-DI outcome is identified, alongside secondary measures covering quality of life, work productivity and activity impairment, function, clinically meaningful improvement, and healthcare resource use. Multiple outcomes can be useful for describing different dimensions of a study, but they also raise a general multiplicity issue: when many statistical questions are examined, interpretation depends on which analyses were prespecified and whether any adjustment or hierarchy was used. A multiplicity strategy is not reported in the registry record.

The record describes the primary analysis population as participants still receiving adalimumab at Week 24 and with HAQ-DI data at baseline and Week 24. It does not report the number in that population. The enrollment of 100 therefore should not be assumed to equal the number contributing to the primary endpoint. How missing measurements were handled, whether any imputation was used, and whether sensitivity analyses were conducted are not reported in the registry record.

These omissions affect interpretation because follow-up availability and continued treatment may be related to participant characteristics or outcomes. In general, analyses limited to those with complete measurements can differ from analyses including all enrolled participants. The registry record does not provide enough information to assess the potential direction or size of any such difference.

The statistical analysis plan, interim analyses, and sample-size justification are not reported in the registry record. The listed planning illustration assumptions do not establish what analysis strategy was actually used. Numeric results for the primary and secondary outcomes are also not reported, preventing assessment of estimates, uncertainty, and consistency across outcomes.

12. 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: hip fracture (1.0%).

The registry lists 100 participants at risk for serious adverse events and one participant affected. It also lists 100 at risk for other adverse events and one participant affected. The death count is zero. The serious adverse event term listed is hip fracture, with a reported frequency of 1.0%.

These counts describe the safety entries recorded in the registry. They do not, by themselves, establish whether an event was caused by adalimumab. The registry record does not provide a causal attribution in the safety details stated. The counts should also be read as separate entries: the record does not establish whether the participant with a serious adverse event was the same participant counted for other adverse events.

Serious adverse events and other adverse events are distinct reporting categories, so the counts should not be added or treated as a single total. The listed term identifies the reported serious event, but the record does not give further clinical details, timing, severity beyond the serious classification, or outcomes for that event. These safety figures are descriptive registry entries and should be interpreted alongside the study’s observational design and the information that is not reported in the registry record.

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

This study addresses an important descriptive question: how HAQ-DI, a patient-reported measure of physical function, changed from baseline to Week 24 among participants with rheumatoid arthritis who continued adalimumab and had measurements at both times. It also planned to assess health-related quality of life, work productivity, and healthcare resource use. The registry describes an observational study in Taiwan in which treatment was prescribed at the physician’s discretion.

The primary outcome’s meaning is defined by the instrument: scores range from 0 to 3, and higher scores indicate greater disability. However, the numeric mean change and its variability are not reported in the registry record. No direction or size of the primary result can therefore be stated, and its precision cannot be assessed from the record. Numeric results for the listed secondary outcomes are likewise not reported in the registry record.

Even a reported change from baseline would be a description of the analyzed participants over time. Because no like-for-like control group or randomized allocation is described, the design cannot, on its own, distinguish treatment-related change from other explanations. This does not erase the value of documenting outcomes in routine practice, but it places a boundary on causal claims.

The primary analysis population excludes, by definition, people who were no longer receiving adalimumab at Week 24 or lacked one of the required HAQ-DI assessments. The number in that population and the handling of missing data are not reported in the registry record. The results therefore cannot be assumed to represent all 100 enrolled participants.

The record supports an account of the intended outcome, its measurement, the observational design, and the reported safety counts. It does not support a conclusion about whether HAQ-DI improved or worsened, how large any change was, or whether adalimumab caused a change. Those questions require outcome estimates and uncertainty information, as well as a design and analysis capable of supporting the relevant comparison.

14. Why This Trial Matters Statistically

Statistically, the study is useful for illustrating the difference between measuring change and estimating a treatment effect. A prospective observational design can collect repeated patient-reported information in routine practice. The primary endpoint, HAQ-DI change from baseline to Week 24, makes the intended within-participant comparison explicit. But a before-and-after contrast is not the same as a randomized comparison with a control group.

The study also highlights the role of the analysis population. The primary endpoint applies only to people still receiving adalimumab at Week 24 with HAQ-DI data at baseline and Week 24. That definition is narrower than enrollment, and the record does not report how many participants met it. Continued treatment and complete follow-up can affect who contributes to an analysis, so the target group for the estimate needs to be kept in view.

HAQ-DI provides a defined, interpretable measure of physical function: a higher score means greater disability. This offers a concrete endpoint for examining change in daily functioning, rather than treating all aspects of health-related quality of life as interchangeable. The registry’s secondary outcomes extend the measurement scope to quality of life, work, and healthcare use, although their numeric results are not reported in the registry record.

Finally, the record demonstrates why statistical interpretation depends on more than a study’s completion status or a named outcome. Numeric estimates, variability, uncertainty intervals, missing-data methods, multiplicity handling, and a clear comparison strategy are needed to assess what the observed data say and how precisely. These details are not reported in the registry record for the primary result. The study can therefore be described as a prospective assessment in routine practice, while its outcome magnitude and causal implications remain unresolved by the recorded information.

15. 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 design is observational, and adalimumab was prescribed according to physician discretion and routine clinical practice. Allocation is not stated, and the registry does not describe a like-for-like control group. Differences in who received treatment, other care, and the course of rheumatoid arthritis can complicate interpretation of change over time. The registry record does not report methods for controlling confounding.

The primary analysis is limited to participants still receiving adalimumab at Week 24 who had HAQ-DI data at baseline and Week 24. The number meeting these conditions is not reported in the registry record. The enrollment of 100 does not establish how many contributed to the primary result. The record also does not explain how missing assessments, treatment discontinuation, or incomplete follow-up were handled.

Most importantly, the numeric primary outcome is not reported in the registry record. The mean change and standard deviation are specified as the planned summary measures, but their values are absent from the available study details. No confidence interval or test result is reported. Numeric results for the secondary outcomes are also not reported, so the magnitude and consistency of changes across domains cannot be assessed.

The registry lists several outcomes and analyses but does not report a multiplicity strategy, statistical analysis plan, interim analyses, or the trial’s own sample-size justification. The planning assumptions described for an illustration do not establish that those assumptions governed the study. These limitations restrict assessment of analysis choices, uncertainty, and causal interpretation, beyond the inherent constraints of the observational design.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Real-World Outcome of Adalimumab on Rheumatoid Arthritis Patients in Taiwan — NCT02616380.
• Registry record last updated 2019-03-14; status last verified 2018-03.
• Results first posted 2019-03-14.
• 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.

19. Record Summary

NCT02616380 is a completed prospective observational study of adalimumab among people with rheumatoid arthritis in Taiwan. The registry records an enrollment of 100, a start date of 2015-11-05, and a primary completion date of 2017-11-23. Treatment was prescribed at the physician’s discretion in routine clinical practice, and no like-for-like control group is described.

The primary outcome was change from baseline in HAQ-DI at Week 24, among participants still receiving adalimumab with data at both assessments. HAQ-DI measures physical function on a scale from 0 to 3, with higher scores representing greater disability. The mean change and standard deviation are specified, but numeric results are not reported in the registry record. The record lists 10 outcome measures and 12 analyses; numeric secondary results are not reported.

The safety entries list one participant with a serious adverse event, one with another adverse event, and zero deaths among 100 at risk in each adverse-event category. Hip fracture is listed as a serious adverse event term at 1.0%. The registry record does not establish causation.