We aim to better understand osteoporotic fracture epidemiology in rheumatoid arthritis (RA) in a West Australian (WA) RA population. We hypothesized increased availability of disease modifying anti-rheumatic drugs (DMARD) and biologic DMARD (bDMARD) would be associated with reducing fracture incidence rates (IR).
Our primary data source, the WA Rheumatic Disease and Epidemiology Registry (WARDER), contains longitudinal health data from Emergency Departments presentations and inpatient admissions (1980-2015). Our primary outcome was first major osteoporotic fracture (MOF), defined as the first occurrence of an International Classification of Disease fracture code at a MOF site (spine, humerus, wrist, or hip and pelvis) after the first RA code. IR are calculated per 1000 patient years (PY) and compared to hospitalised rheumatic disease-free controls using IR ratios (IRR) stratified into 1990-2000 and 2000-2010.
Just under one-in-four RA patients (4157/17368) experienced a first fracture from 1980-2015. From 1990-2000 to 2000-2010 RA fracture IR increased from 11.64 (95% CI 10.78-12.54) to 18.3 (95% CI 15.7-21.2), while IRR increased from 1.18 (95% CI 1.07-1.31) to 1.32 (95% CI 1.10-1.60). Similarly, IR of MOF increased from 6.80 (95% 6.15-7.50) to 9.99 (95% 8.10-12.19), and FF code IR from 4.01 (3.52-4.56) to 4.33 (3.12 – 5.85).
RA patients fracture risk exceeds other hospitalised patients and continues to increase, despite advances in RA medications and changing goals of treatment, ie low disease activity or remission. The reason for the high risk and increasing risk warrants further review and management.