Additional diagnostic value of anti-cyclic citrullinated peptide antibodies compared with rheumatoid factor isotypes, taking into account disease duration, radiological damage, and disease activity
| All | IgG/IgA/IgM-RF negative, CCP positive | IgM-RF negative, CCP positive | IgG-RF negative, CCP positive | IgA-RF negative, CCP positive | |
|---|---|---|---|---|---|
| Values are n (%). | |||||
| *Disease duration. | |||||
| ACR, American College of Rheumatology disease activity score; CCP, anti-cyclic citrullinated peptide antibodies; Ig, immunoglobulin; Larsen, Larsen radiological score21; RA, rheumatoid arthritis; RF, rheumatoid factor. | |||||
| All RA patients | 295 (100) | 30 (10.2) | 38 (12.9) | 86 (29.2) | 67 (22.7) |
| <1 year* | 97 (32.9) | 14 (14.4) | 15 (15.5) | 30 (30.9) | 26 (26.8) |
| 1–5 years* | 59 (20.0) | 3 (5.1) | 6 (10.2) | 12 (20.3) | 7 (11.9) |
| >5 years* | 139 (47.1) | 13 (9.4) | 17 (12.2) | 44 (31.7) | 34 (24.5) |
| Larsen 0–1 | 109 (36.9) | 9 (8.3) | 10 (8.3) | 30 (27.9) | 22 (20.2) |
| Larsen 2–3 | 115 (39.0) | 10 (8.7) | 15 (13.0) | 33 (28.7) | 23 (20.0) |
| Larsen 4–5 | 71 (24.1) | 11 (15.5) | 13 (18.3) | 23 (32.4) | 22 (31.0) |
| ACR <35 | 130 (44.1) | 11 (8.5) | 14 (10.8) | 41 (31.5) | 31 (23.9) |
| ACR 35–65 | 106 (35.9) | 9 (8.5) | 12 (11.3) | 28 (26.4) | 24 (22.6) |
| ACR >65 | 59 (20) | 10 (17.0) | 12 (20.3) | 17 (28.9) | 12 (20.3) |