Reduction in Upper Limb Joint Surgery among Rheumatoid Arthritis Patients: An Interrupted Time Series Analysis using Danish Health Care Registers.
Cordtz R., Hawley S., Prieto-Alhambra D., Højgaard P., Zobbe K., Kristensen LE., Overgaard S., Odgaard A., Soussi BG., Dreyer L.
OBJECTIVES: Joint replacement surgery is a proxy of severe joint damage in rheumatoid arthritis (RA). The aim of this study was to assess the impact of the introduction of biological DMARDs (bDMARDs) on the incidence rate (IR) of upper limb joint replacements among newly diagnosed RA patients. METHODS: Using the Danish National Patient Register, incident RA patients from 1996-2012 were identified. Each patient was matched on age, sex and municipality with up to 10 general population controls. Age and sex standardised 5-year IR per 1000 person-years (PY) of a composite outcome of any first joint replacement of the finger, wrist, elbow, or shoulder was calculated; and an interrupted time series analysis was undertaken to investigate trends and changes of the IR in the pre-bDMARD (1996-2001) and the bDMARD era (2003-2012) with a 1-year lag period in 2002. RESULTS: In total, 18 654 incident patients with RA were identified (mean age 57.6 years, 70.5% women). The IR of joint replacements among RA patients was stable at 2.46/1000 PY (95%CI 1.96-2.96) from 1996 to 2001 but started to decrease from 2003 onwards (-0.08/1000 PY annually, 95%CI -0.20 to +0.02). Compared with RA, the IR among controls in 1996 was 1/17 and it increased continuously throughout the study period. CONCLUSION: The IR of upper limb joint replacements started to decrease among RA patients from 2002 onwards, whereas it increased among controls. Our results suggest an association between the introduction of bDMARDs and a lower need of joint replacements among RA patients. This article is protected by copyright. All rights reserved.