Clinical Outcomes of Patients with Active Rheumatoid Arthritis with Normal Acute-Phase Reactant Values

Abstract

Background/Purpose:

Despite high clinical disease activity measured by joint counts and global assessments, some patients with active rheumatoid arthritis (RA) have normal acute-phase reactant (APR) values. This group of patients may have less aggressive disease or may represent earlier phase of the disease, but clinical outcomes of these patients were not previously explored.

We aimed to determine the clinical outcomes of patients with clinically active RA but has normal APR values.

Methods:

Of 2,583 patients with RA enrolled in the KORean Observational study Network for Arthritis (KORONA) registry, 400 patients who had Clinical Disease Activity Index (CDAI) score of >2.8 at baseline, biologic-naïve, and ESR and CRP drawn at both baseline and two-year follow-up visits were identified. Patients were grouped according to baseline APR levels; neither elevated ESR nor CRP (normal APRs), either ESR or CRP elevated (one APR-positive), and both elevated ESR and CRP (both APRs-positive).

Results:

Of patients with active RA, 39% had normal APR; 27% were one APR-positive; only 34% had both APRs-positive. Baseline tender and swollen joint counts, CDAI and HAQ-DI scores were significantly lower in normal APRs group compared with APRs-positive groups (p<0.0001). However, mean disease duration was not significantly different between 3 groups. At two-year follow-up, mean DAS28 scores were lower in normal APRs group (p<0.0001), and CDAI scores showed trend toward lower values (p=0.062). Patients with normal APRs were less likely to use glucocorticoids and biologics. Although remission rate was comparable in 3 groups when measured by CDAI, DAS28 remission rate was significantly in higher normal APRs group.

Conclusion:

Active RA patients with normal APRs have milder disease, better clinical outcomes and require less aggressive treatment compared with APRs-positive patients. Composite disease activity measures which do not include APRs should be considered for monitoring disease activity in patients with normal APRs because disease activity indexes including APRs in its scoring result in underestimation of their disease activity.