Patients with clinically suspect arthralgia who have circulating anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF), are at an increased risk of clinical arthritis progression, according to research presented at the American College of Rheumatology 2016 annual meeting.1
Over a 12 month period, Robin M ten Brinck, PhD candidate from the Department of Rheumatology at Leiden University Medical Center, the Netherlands, and colleagues evaluated 255 patients with clinically suspect arthalgia and considered by their physician at risk of developing rheumatoid arthritis (RA).
Over a follow-up period of 96 weeks, patients with suspect arthralgia were monitored for serological positivity for immunogloubin M-rheumatoid factor (IgM-RF), ACPA, and anti-carbamylated protein, to determine which of these factors contributed to the development of clinical arthritis.
Of the patients who were ACPA- and RF-positive, 45 developed clinical arthritis. Specifically, patients who subsequently developed arthritis were more likely to be RF-positive (hazard ratio [HR] = 4.8; 95% CI, 2.7 – 8.7), ACPA-positive (HR=7.9, 95%CI=4.4-14.3), and anti-carbamylated protein-positive (HR = 3.7, 95% CI = 1.9 – 7.3).
Only ACPA-seropositivity remained significantly associated with future arthritis development after multivariable Cox regression analyses (HR=5.0, 95%CI=1.9-12.9).
Among patients who were RF-positive and ACPA-positive, the highest HR was 9.5 (95% confidence interval [CI], 4.9 – 18.3), compared with patients who were both RF-negative and ACPA-negative. There were no significant differences between patients who were RF-positive and patients who were RF-negative.
Although nearly 70% of ACPA-positive/RF-positive patients progressed to clinical arthritis, the remaining 30% did not develop clinical arthritis during a median follow-up duration of 96 weeks.
”Patients with clinically suspect arthralgia experience arthralgia of metacarpophalangeal, proximal interphalangeal or wrist joints that, according to the rheumatologist, is suspect to progress to rheumatoid arthritis. However, no clinical arthritis is yet detectable at psychical examination at baseline,” Mr ten Brinck told Rheumatology Advisor in an interview.
“Within patients with clinically suspect arthralgia, anti–citrullinated protein antibody (ACPA)—possibly in combination with RF—was associated with increased risks on progression to clinical arthritis. However, 33% of the ACPA-positive/RF-positive patients do not progress to clinical arthritis within 2 years, despite experiencing clinically suspect arthralgia. No baseline differences were found for ACPA-positive/RF-positive patients who did progress and did not progress to clinical arthritis. This indicates that information on autoantibodies alone is insufficient to adequately predict autoantibody-positive rheumatoid arthritis.”
- ten Brinck RM, van Steenbergen HW, Verheul MK, et al. The prognostic value of different auto-antibodies for arthritis development in patients with clinically suspect arthralgia. Presented at: ACR/ARHP Annual Meeting; November 11-16, 2016; Washington D.C. Abstract #1035.
This article originally appeared on Rheumatology Advisor