C-reactive protein levels in patients with rheumatoid arthritis: the impact of therapy.

C-reactive protein levels were measured in sera of 111 patients with rheumatoid arthritis and were compared with erythrocyte sedimentation rate. The patients were divided into six groups according to drug therapy. Comparison between the groups suggests that CRP correlates best with ESR in patients treated with penicillamine and in patients in clinical remission. Patients treated with gold, NSAID or methotrexate have a weaker correlation between the two parameters, while steroid therapy yields the poorest correlation which is not statistically significant. Our data suggest that although CRP is a sensitive index of disease activity, the specific drug taken by the patient must be considered before interpreting the results.