The Association Between Anticyclic Citrullinated Peptide Antibodies and Risk of Rheumatoid Arthritis

• Activity Number: 209
• Type: Contributed
• Date/Time: Monday, July 30, 2007 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Lori B. Chibnik*+ and Lisa A. Mandl and Karen H. Costenbader and Peter Schur and Elizabeth W. Karlson
• Companies: Brigham and Women's Hospital and Hospital for Special Surgery and Brigham and Women's Hospital and Brigham and Women's Hospital and Brigham and Women's Hospital
• Keywords: sensitivity ; specificity ; biomarker ; Arthritis ; Rheumatology

Abstract

Anticyclic citrullinated peptide antibodies (CCP) are strongly associated with an increased risk of rheumatoid arthritis (RA). It is unclear if the manufacturer's recommended cut-off is optimal, or if continuous values are useful. Using two large prospective Nurses Health Study Cohorts, we examined sensitivity, specificity and mean time to RA onset at five thresholds of CCP, and also evaluated the utility of continuous titers. Incident RA was confirmed in 93 women, with three matched controls/case. Plasma was tested for CCP with the DIASTATTM ELISA assay. Results showed a threshold lower than recommended has superior test performance, higher sensitivity but low specificity. Higher titers are strongly associated with a shorter time to disease onset. Although dichotomized results are clinically meaningful, higher ranges of the titer are informative in predicting sooner development of RA.