Objective: To elucidate the potential contribution of high sensitivity C-reactive protein (hs-CRP) testing in the assessment of disease activity in rheumatoid arthritis (RA).
Methods: We recorded clinical and psychological variables, the hs-CRP, and erythrocyte sedimentation rate (ESR) in 146 consecutive patients with RA. We analyzed the associations between the ESR and hs-CRP versus the other recorded variables.
Results: The median (interquartile range) ESR (mm/h) and hs-CRP (mg/l) were 15 (7-36) and 5 (2.3-13.9), respectively. Thirty-two (22%) patients had an hs-CRP < 2 mg/l, 61 (42%) an hs-CRP of 2-8 mg/l and 53 (36%) an hs-CRP > 8 mg/l. In patients with an hs-CRP of 2-8 mg/l, the swollen joint counts and the physician disease activity scales were higher, and remission rates were lower than in patients with an hs-CRP of < 2 mg/l. The hs-CRP was consistently more closely associated with disease activity, depression, and helplessness than was the ESR.
Conclusion: High sensitivity CRP testing reveals systemic inflammation that is generally not detectable with routine CRP assays and that is associated with disease activity in RA.