Risk and predictors of fractures in early rheumatoid arthritis - A long term follow up study of an inception cohort.

OBJECTIVES

To examine the risk of fractures in a cohort of patients with newly diagnosed rheumatoid arthritis (RA), compared to the background population, and predictors of fractures detectable early in RA.

METHODS

An inception cohort of patients with RA (N = 233; 164 women/69 men, recruited 1995-2005) was evaluated according to a structured program, including repeated clinical assessments and measures of bone mineral density (BMD), from diagnosis to 10 years later. Matched population controls were identified using the national census register. Fractures through 2019 were identified based on ICD codes. Cox regression models were used to assess the risk of fractures in RA patients compared with controls, and for assessment of potential predictors for fractures in the RA population.

RESULTS

RA patients had an increased risk of fractures (fully adjusted hazard ratio (HR) 1.52, 95 % CI 1.13; 2.06). In the RA cohort, high age, low body mass index, and low BMD were significant baseline predictors of future fractures in multivariate analyses, but baseline RA disease characteristics were not. Worse disability (i.e. higher Health Assessment Questionnaire (HAQ) scores) over time was significantly associated with increased risk of fractures (age-sex-adjusted HR 1.33 per SD, 95 % CI 1.09; 1.63) and there was an inverse association between BMD Z-scores over time and fractures.

CONCLUSION

Patients with RA had higher risk of fractures than controls. Fracture risk was related to BMD at baseline and over time in patients with RA. In addition, worse disability (measured by HAQ) over time was associated with higher risk of fractures.