Objectives: Around 1% of the population test positive for anti-cyclic citrullinated peptide (anti-CCP) antibodies. This biomarker predicts progression to rheumatoid arthritis (RA) but over a variable time-frame. To increase its clinical relevance, this study sought to determine (1) if the proportion of anti-CCP positive individuals could be enriched by case selection of people attending primary care with new nonspecific musculoskeletal (MSK) symptoms but without clinical synovitis (CS) and (2) whether these individuals progress rapidly to inflammatory arthritis (IA), in particular RA. Methods: In this prospective cohort study, individuals age ≥18 years with new nonspecific MSK symptoms, without CS, were recruited from primary care in the U.K. Anti-CCP positive individuals were invited for follow-up in the rheumatology department, Leeds. Those who tested negative were sent questionnaires 12 months later. Results: 2028 individuals were recruited. Of these 2.8%(57/2028) were anti-CCP positive, of whom 47%(27/57) developed IA ,24 RA (also 1 undifferentiated IA (UIA), and 2 polymyositis); 92.6%(25/27) within 12 months, median 1.8 months(IQR 1.0-4.3, range 0.3 to 16.1). Of the anti-CCP negative individuals, 1.3% (20/1559) developed IA (1 UIA, 13 RA, 6 psoriatic arthritis); 75%(15/20) within 12 months. The RR for developing RA within 12 months in the anti-CCP positive group was 66.8(32.2-138.4, p<0.001); for IA it was 45.5(95%CI 25.4-81.6, p<0.001). Conclusions: Selecting individuals with new nonspecific MSK symptoms without CS enriched the prevalence of anti-CCP positivity to 2.8%. Those who tested positive had a high risk of rapidly developing RA. The cost effectiveness of this approach will need to be determined.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)