US trends in rates of arthroplasty for inflammatory arthritis including rheumatoid arthritis, juvenile idiopathic arthritis, and spondyloarthritis

Objective: Although rates of arthroplasty have increased dramatically, rates among patients with rheumatoid arthritis (RA) are reported to be decreasing. It is not known if this is also the case among patients with other inflammatory arthritides. This study was undertaken to evaluate rates of arthroplasty due to RA, juvenile idiopathic arthritis (JIA), spondyloarthritis (SpA), and a composite group of patients with inflammatory arthritides (IA), compared to arthroplasty rates among patients without inflammatory or autoimmune conditions.

Methods: Administrative discharge databases (State Inpatient Databases of the Healthcare Cost and Utilization Project, New York Department of Health Statewide Planning and Research Cooperative System, California Statewide Health Planning and Development) were used to compare rates of knee, hip, and shoulder arthroplasty occurring from 1991 to 2005.

Results: Of 2,839,325 arthroplasties in 1991-2005, 2.7% were performed in patients with IA. The rate of arthroplasty for noninflammatory conditions doubled (124.5 per 100,000 persons in 1991 versus 247.5 per 100,000 persons in 2005), while the rate for IA remained stable at 5.1 per 100,000. Rates of arthroplasty for RA decreased slightly (4.6 per 100,000 versus 4.5 per 100,000) and those for JIA decreased by nearly 50% (0.22 per 100,000 versus 0.13 per 100,000), but the rate of arthroplasty for SpA increased by nearly 50% (0.22 per 100,000 versus 0.31 per 100,000). Age at the time of arthroplasty increased for patients with RA (mean ± SD 63.4 ± 12.7 years versus 64.9 ± 12.8 years), JIA (30.9 ± 12.2 years versus 36.7 ± 14.9 years), and SpA (54.3 ± 16.1 years versus 60.4 ± 13.9 years). However, the mean age at the time of arthroplasty among non-IA cases decreased (71.5 ± 11.8 years versus 69.0 ± 12.0 years).

Conclusion: This population-based study is the first to show that arthroplasty rates have decreased significantly among patients with JIA and minimally among patients with RA, and have increased among patients with SpA. The increased age at the time of arthroplasty among patients with JIA and SpA suggests that these patients are increasingly able to defer surgical interventions. Further research is needed to assess the ongoing effect of biologic agents on the need for arthroplasties in patients with IA.