Background/Purpose : Seropositive and seronegative rheumatoid arthritis (RA) differ in course and prognostic feature. The overall incidence of orthopaedic surgery in patients with RA has previously been shown to decline over time. The purpose of this study was to investigate whether there were differences in the time trends for orthopaedic surgery in rheumatoid factor (RF) positive and RF negative RA.

Methods: A population-based dynamic cohort of all known patients with RA in a defined geographic area was investigated. The patients had a clinical diagnosis of RA made by a rheumatologist, and fulfilled the 1987 ACR criteria for RA. Data on orthopaedic surgery procedures between 1998 and 2011 were retrieved from a regional health care register. Incidence rates of orthopaedic surgery procedures after RA diagnosis during the period from 1998 through 2011 were estimated separately for RF positive and RF negative patients. The incidence rates for 1998-2001 were compared to those of 2002-2006 and 2007-2011.

Results: A cohort of 2095 patients with RA (72 % women, 69 % RF positive) was investigated. There were 1702 orthopaedic procedures during a total follow-up of 21,123 person-years (py). Patients with RF positive RA were treated more extensively with methotrexate and biologic disease modifying anti-rheumatic drugs than those with RF negative RA. The incidence of orthopaedic surgery procedures overall declined significantly over time for RF positive RA, and there was a corresponding decline in small joint surgery and large joint surgery (Table). In patients with RF positive RA, the incidence of large joint surgery was reduced already in 2002-2006 compared to 1998-2001, whereas a decline in small joint surgery was apparent only in the final period (2007-2011). The incidence rate ratio (IRR) for orthopaedic surgery overall in this subset compared to 1998-2001 was 0.83 (95% confidence interval (CI) 0.73-0.95) in 2002-2006, and 0.68 (95% CI 0.59-0.79) in 2007-2011. On the other hand there was no significant decline among patients with RF negative RA in the incidence of all orthopaedic surgery procedures, with similar findings for small joint surgery or large joint surgery (Table). In patients with RF negative RA, the IRR for surgery overall compared to 1998-2001 for 2002-2006 was 0.90 (95% CI 0.68-1.18), and for 2007-2011 0.80 (95% CI 0.60-1.06).

Conclusion: The overall incidence of orthopaedic surgery declined over time in patients with RF positive RA, with significant decreases in both large and small joint surgery. In contrast, there was no major decline in RF negative RA. Patients with seropositive RA may benefit more from improved management and modern anti-rheumatic pharmacotherapy in terms of reduction of joint damage and the need for joint surgery.

Incidence of orthopaedic surgery per 1000 py (95 % CI) in the population-based RA cohort

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-decrease-over-time-of-orthopaedic-surgery-in-patients-with-rheumatoid-arthritis-is-mainly-due-to-reduced-rates-among-those-with-rheumatoid-factor-positive-disease-ae-results-from-a-well-d/