Background/Purpose:

Fragility fractures represent one of the serious extra-articular manifestations of rheumatoid arthritis (RA). The aim of this study was to investigate whether fracture incidence differs between patients with early RA and the general population.

Methods:

The patients were recruited from the BARFOT (Better Anti-Rheumatic FarmacO Therapy) cohort, which is a Swedish multicentre observational study of patients with early RA (disease duration ≤ 12 months at inclusion). All patients fulfilled the 1987 American College of Rheumatology classification criteria and were included between 1992 and 2006. Each patient was matched by sex, age and residential area (at the   date of inclusion into the BARFOT) with 4 population controls. Controls without diagnosed RA were randomly selected from the general population using data from the Swedish Central Statistics Office. Incidental fractures were identified through the Swedish Inpatients Register, the Swedish Outpatients Register and the Swedish Cause of Death Register until December 2013. In this study, fractures of wrist, upper arm and hip were considered, as these locations of fractures are supposed to be typical for fragility fractures and can be accurately defined through the registries. The first fracture and total number of all fragility fractures throughout the study period were considered. Fracture incidence rates were calculated and Kaplan-Meier analysis was used to compare the time to the first fracture and rate of fracture occurrence among RA patients and in matched population controls. Analysis were performed for the total study population and also stratified by inclusion period; 1992-1999 and 2000-2006. 

Results:

During a mean (SD) follow-up period of 14 (3.9) years 617 of 2751 (22.4%) patients with RA and 1898 of 11004 (17.2%) of controls experienced a fracture (p <0.001). Compared with controls, patients with RA had an increased risk of fractures in upper arm, OR (95% CI) 1.43 (1.12-1.83); p=0.005, hip, OR 1.45 (1.23-1.72); p<0.001, and other fractures, OR 2.72 (1.57-3.28); p<0.001), but not in wrist, OR 1.04 (0.85-1.26); p=0.714. Except for wrist fractures, the number of fractures/1000 person-years was significantly increased in RA-patients (upper arm 2.9 vs. 1.9; hip 6.7 vs. 4.8; other 2.5 vs. 1.4). In total population and in the groups stratified by inclusion periods, the mean times to the first fracture in upper arm, hip and fragility fractures of other locations were shorter in patients than in controls.

Conclusion:

In this study we observed an increased risk of fragility fractures in patients with early RA compared with matched population controls. Further studies are needed to explain the increased fracture risk in patients with RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/increased-fracture-risk-in-patients-with-early-rheumatoid-arthritis-a-prospective-general-population-matched-cohort-study/