Increasing fracture incidence over 13 years in patients with rheumatoid arthritis from the IORRA cohort

Abstract

Introduction: This study aimed to evaluate fracture incidence in patients with rheumatoid arthritis (RA) over 13 years in the Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort study.

Materials and methods: The IORRA is a prospective observational cohort study of Japanese patients with RA. Between 2011 and 2023, 10,257 patients with RA were enrolled. Clinical parameters and data on fractures were collected biannually using self-reported questionnaires. The fracture incidence, standardized by sex, age, and Japanese Health Assessment Questionnaire score, was calculated for each two-year period.

Results: From 2011 to 2023, the proportions of patients achieving Disease Activity Score in 28 joints remission, using biologic disease-modifying antirheumatic drugs, and taking osteoporosis medications increased (38.0% to 64.7%, 14.2% to 42.2%, and 31.6% to 38.3%, respectively), while the proportion of glucocorticoid use decreased (38.3% to 22.2%). The incidence of all and non-vertebral fractures increased from 47.2 and 36.7/1000 person-years in 2011 to 52.8 and 43.0/1000 person-years in 2023, respectively. Using 2023 as the reference, the standardized incidence ratios for all and non-vertebral fractures were: 2011-2012, 0.90 [95% confidence interval (CI) 0.82-0.98] and 0.86 (95% CI 0.78-0.95); 2013-2014, 0.88 (95% CI 0.81-0.96) and 0.84 (95% CI 0.76-0.93); 2015-2016, 0.94 (95% CI 0.86-1.02) and 0.89 (95% CI 0.80-0.98); 2017-2018, 0.97 (95% CI 0.88-1.07) and 0.94 (95% CI 0.84-1.05); 2019-2020, 0.95 (95% CI 0.84-1.07) and 0.93 (95% CI 0.81-1.06); 2021-2022, 1.00 (95% CI 0.89-1.13) and 0.99 (95% CI 0.86-1.13).

Conclusion: Despite advancements in RA management over 13 years, fracture incidence may have increased in patients with RA.

Keywords: Japanese; Non-vertebral fracture; Osteoporosis; Rheumatoid arthritis; Standardized incidence ratio.