Is anti-CCP antibody useful for prediction of progression to RA in patients with ‘arthralgia’? A 1-year follow-up study of 100 patients with a chief complaint of arthralgia

Abstract

    Many patients visit primary care clinics to seek medical care for arthralgia. Among these patients are those with non-inflammatory diseases, who often get better only by taking rest and/or conservative treatment. If they have inflammatory diseases such as rheumatoid arthritis (RA), however, they should be correctly diagnosed and treated at an early stage. Anti-CCP antibody is an autoantibody specific for RA and is of great help for the diagnosis of RA in ‘arthritis’ patients. The usefulness of anti-CCP antibody in patients with ‘arthralgia’ remains to be clarified in terms of the diagnosis of ambiguous early-stage RA. We measured this antibody in 100 patients who visited our outpatient clinic for a chief complaint of joint pains, and followed them up until 1 year later to study whether this antibody would be helpful in the prediction of RA development or in the diagnosis of RA. At the initial examination, 40% of those patients were positive for the antibody. After the one-year follow-up, 30 (75%) of the 40 antibody-positive cases were classified as having RA, while only 4 (7%) of the 60 antibody-negative cases were found to have RA (p＜0.001). Specificity of the antibody testing was as high as 84.9%, indicating that the anti-CCP antibody measurement appears to be useful for prediction of RA development and helpful for RA diagnosis in patients with ‘arthralgia’.