Background/Purpose: Rheumatoid Arthritis (RA) has been associated with increased risk of osteoporosis and fractures. We have recently presented results on DXA measurements over 10 years in patients with newly diagnosed RA, where women were shown to retain their bone mineral density (BMD) fairly well compared with the reference population whereas men with early RA had reduced BMD in the femoral neck at diagnosis and after 5 years of follow-up [1]. To what extent such patterns have an impact on fracture risk in established RA is an issue of major clinical importance. The aim of this study was to survey the risk of fragility fractures in a community-based sample of patients with RA, compared with controls without RA from the same area.

Methods: A dynamic community-based cohort of patients with RA (n=1928) was investigated. Prevalent cases identified in 1997, and incident cases from 1997-2006 were included. Four controls per patient were matched for age, sex and residential area. Information on fractures in patients and controls during the period 1. July 1997 to 31. December 2017 was obtained by linkage to the Swedish National Patient Register and the Cause of Death Register. Fractures of the hip, upper arm, forearm and vertebra were identified based on ICD-9 and ICD-10 diagnostic codes. Patients and controls with identified fractures before study start were excluded. The incidence of fractures was estimated in RA patients and controls, stratified by sex. The relation between RA and the risk of fractures in women and men was assessed using Cox regression models.

Results: Of the patients included, 73 % were women and 73 % were rheumatoid factor positive. The mean age at inclusion in men was 61 years and in women 60 years. Mean duration of disease was 8 years in men and 9 years in women. A total of 51 (9.7%) men and 202 (14.4%) women with RA suffered from at least one of the studied fractures during the study period, compared to 119 (5.6%) male and 604 (10.8%) female controls (Table 1). Men with RA had increased risk of fragility fractures overall (hazard ratio (HR) 1.55, 95% Confidence Interval (CI) 1.03; 2.34) and of fractures in the hip (HR 1.68, 95% CI 1.05; 2.68). Women with RA also had increased risk of fragility fractures overall (HR 1.52, 95% CI 1.27; 1.83), of fractures in the hip (HR 1.41, 95% CI 1.14; 1.75) and in the upper arm (HR 2.11, 95% CI 1.43; 3.12). There was a similar trend in the vertebral column but not in the forearm (Table 2).

Conclusion: In this cohort of patients with RA, the risk of fragility fractures was increased in both men and women compared with controls without RA. For men the results are in line with previous findings of reduced femoral neck BMD in early RA. For women with RA, long term changes in BMD in established disease, or other disease related factors, may be of importance in the assessment of fracture risk.

1. Theander L, Willim M, Nilsson JÅ, et al. Changes in bone mineral density over 10 years in patients with early rheumatoid arthritis. RMD Open 2020;6(1):e001142.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-risk-of-fractures-in-a-community-based-cohort-of-patients-with-rheumatoid-arthritis-compared-with-the-background-population/