Table 5.
Diagnostic value of anti-filaggrin autoantibodies and rheumatoid factors for RA in the cohort of very early arthritis patients (group 2)
| Autoantibody | Sensitivity | Specificity | PPV | NPV | Odds ratio [95% CI] |
|---|---|---|---|---|---|
| RF-IgM | 35·2 | 92·1 | 92·5 | 33·7 | 5·8 [2·3–14·6] |
| AKA | 22·7 | 96·8 | 95·2 | 30·9 | 7·3 [2–27·1] |
| APF | 38·1 | 95·2 | 95·7 | 35·5 | 10·6 [3·5–32·6] |
| dACRF | 30·7 | 98·4 | 98·2 | 33·7 | 18·5 [3·5–96·5] |
| Anti-CCP | 39·2 | 95·2 | 95·8 | 35·6 | 11·1 [3·6–34·2] |
| AKA or APF | 39·8 | 92·1 | 93·3 | 35·3 | 7.0 [2·8–17·7] |
| dACRF or anti-CCP | 40·9 | 95·2 | 96 | 36·5 | 12.0 [3·9–36·7] |
| AKA or APF or dACRF | 42·6 | 90·5 | 92·6 | 36 | 6·6 [2·7–15·6] |
| AKA or APF or anti-CCP | 47·7 | 87·3 | 91·3 | 37·4 | 6.0 [2·7–13] |
| AKA or APF or anti-CCP or dACRF | 48·9 | 87·3 | 91·5 | 37·9 | 6·2 [2·9–13·6] |
| (AKA or APF) and RF-IgM | 26·1 | 98·4 | 97·6 | 32·3 | 14·8 [2·8–77·6] |
| dACRF and RF-IgM | 26·1 | 100 | 100 | 32·6 | 45·0 [2·7–746] |
| anti-CCP and RF-IgM | 29·5 | 100 | 100 | 33·6 | 53·5 [3·2–882] |
PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval; RF, rheumatoid factor; AKA, anti-keratin antibodies; APF, anti-perinuclear factor; dACRF, autoAb recognizing citrullinated minus noncitrullinated rat filaggrin; anti-CCP, anticyclic citrullinated peptides.