Prevalence and clinical prediction of osteoporosis in a contemporary cohort of patients with rheumatoid arthritis

Objective: Osteoporosis has previously been reported to be twice as common in patients with RA as in controls, but these studies predate the introduction of aggressive management of RA. The aim of this study was to evaluate the prevalence and clinical predictors of osteoporosis in RA in a contemporary cohort and to develop a clinical tool for the identification of patients at risk.

Methods: The prevalence of osteoporosis was related to clinical and demographic variables in 304 consecutive RA patients undergoing DXA at a single centre between 2009 and 2010 and compared with the frequency of osteoporosis in a population-based cohort of 903 subjects.

Results: The RA cohort was predominantly female (81.9%), with an average age of 63.5 years (s.d. 11.8) and a disease duration of 9.6 years (s.d. 10.2). Osteoporosis was present in 91 (29.9%) patients at either the spine or total hip compared with 157/903 (17.4%) of age- and gender-matched controls. In RA patients, osteoporosis was associated with female gender (P = 0.002), age (P < 0.001), time since menopause (P < 0.001), BMI (P < 0.001), ESR (P = 0.006), Larsen score (P = 0.011) and co-morbidities (P = 0.020), but logistic regression analysis showed that only age and BMI were independent predictors. A predictive tool based on age and BMI was developed that had 91.4% sensitivity for the detection of osteoporosis in an independent RA population.

Conclusion: The prevalence of osteoporosis in RA remains high in the modern era despite aggressive management and the use of biologic therapy. Most RA patients with osteoporosis can be identified by a simple algorithm taking age and BMI into account.