Age-adjusted and multivariate associations of autoantibodies with proportion of time in remission and disease activity score (DAS28) area under the curve (AUC)*
| Age-adjusted associations | Multivariate associations | |||
|---|---|---|---|---|
| aCCP β coefficient (p value) | RF β coefficient (p value) | aCCP β coefficient (p value) | RF β coefficient (p value) | |
| Proportion of time in remission | ||||
| Seronegative | Referent | Referent | Referent | Referent |
| Seropositive | −0.08 (0.044) | −0.10 (0.047) | −0.06 (0.057) | −0.06 (0.023) |
| Seronegative | Referent | Referent | Referent | Referent |
| Low positive | −0.04 (0.291) | −0.04 (0.393) | −0.04 (0.251) | −0.03 (0.272) |
| Moderate positive | −0.09 (0.005) | −0.13 (0.031) | −0.06 (0.047) | −0.08 (0.026) |
| High positive | −0.11 (0.037) | −0.15 (0.010) | −0.07 (0.042) | −0.09 (0.002) |
| Continuous concentration† | −0.008 (0.009) | −0.005 (0.002) | −0.004 (0.017) | −0.003 (0.006) |
| DAS 28 AUC | ||||
| Seronegative | Referent | Referent | Referent | Referent |
| Seropositive | 0.28 (0.016) | 0.45 (0.007) | 0.18 (0.023) | 0.28 (0.001) |
| Seronegative | Referent | Referent | Referent | Referent |
| Low positive | 0.13 (0.175) | 0.23 (0.088) | 0.08 (0.425) | 0.18 (0.064) |
| Moderate positive | 0.34 (0.005) | 0.49 (0.008) | 0.19 (0.018) | 0.26 (<0.001) |
| High positive | 0.38 (0.045) | 0.65 (0.001) | 0.28 (0.081) | 0.41 (<0.001) |
| Continuous concentration† | 0.03 (0.006) | 0.02 (0.003) | 0.02 (0.092) | 0.01 (0.007) |
↵* Seropositivity defined as ≥5 U/ml for aCCP and ≥15 IU/ml for RF. For aCCP concentration categories: low positive ≥5 to 126.3 U/ml, moderate positive ≥126.3 to 333.2 U/ml and high positive ≥333.21 For RF concentration categories: low positive ≥15 to 89.5 IU/ml, moderate positive ≥89.5 to 340.5 IU/ml and high positive ≥340.5 IU/ml. Covariates included in multivariate analysis include race/ethnicity (Caucasian vs non-Caucasian), education, disease duration, follow-up time, smoking status, comorbidity count, pharmacological interventions and disease status (DAS28 ≤2.6 vs DAS28 >2.6) at enrolment.
↵† Per 100-unit increment.
aCCP, anti-cyclic citrullinated peptide antibody; RF, rheumatoid factor.