Missing Anticitrullinated Protein Antibody Does Not Affect Short-term Outcomes in Early Inflammatory Arthritis: From the Canadian Early Arthritis Cohort
Bibliographic record
Abstract
OBJECTIVE: Anticitrullinated protein antibody (ACPA) is as sensitive as, but more specific than, rheumatoid factor (RF) and is detected earlier in rheumatoid arthritis (RA). Although part of the RA classification criteria, ACPA testing is not routinely paid for/accessible in all jurisdictions. The effect of missing ACPA testing was studied to determine whether failure to perform ACPA testing could cause a care gap in early inflammatory arthritis. METHODS: Nearly 2000 patients (n = 1998) recruited to an early inflammatory arthritis cohort were allocated into 3 groups: (1) seropositive (either RF+ or ACPA+), (2) seronegative (RF- and ACPA-), and (3) missing ACPA and RF-. Analyses were adjusted for age, sex, symptom duration, and smoking status if p < 0.1. Disease Activity Score at 28 joints (DAS28) at 3 months was studied, because beyond then, disease activity is expected to determine ongoing treatment. RESULTS: More seropositive patients fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism RA criteria than seronegative patients. Group 3 was slightly older and had a smaller percentage of females, as well as shorter symptom duration and less smoking. At 3 months, group 3 was treated with fewer disease-modifying antirheumatic drugs and methotrexate (p < 0.00002) than groups 1 and 2, but there were no significant differences in DAS28, Health Assessment Questionnaire-Disability Index (HAQ-DI), proportion receiving corticosteroids, or physician's/patient's global assessments. CONCLUSION: There was no care gap in the RF-negative, unknown ACPA group because there were no significant differences in the DAS28, 3-month change in DAS28, or HAQ-DI, despite less treatment. Cost-effectiveness of ensuring ACPA testing availability in suspected RA is unknown because early outcomes did not differ, whether or not ACPA was available.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".