Prevalence and predictors of fragility fractures in systemic lupus erythematosus
- 1Department of Rheumatology, University of Birmingham, Birmingham, UK
- 2Department of Nuclear Medicine, University Hospital Birmingham
- 3Department of Rheumatology, University Hospital Birmingham
- 4Department of Rheumatology, City Hospital, Birmingham
- Correspondence to:
Dr Caroline Gordon
Department of Rheumatology, Medical School, University of Birmingham, Birmingham B15 2TT, UK;
- Accepted 16 March 2004
Objective: To establish the prevalence of reduced bone mineral density (BMD) and fractures, and risk factors for fractures, in a cross sectional study of a large cohort of patients with systemic lupus erythematosus (SLE).
Methods: All SLE patients willing to take part in the study had bone densitometry in 1999/2000 and completed a questionnaire on risk factors for osteoporosis and on drugs used. Accumulated damage was scored using the SLICC/ACR damage index (SDI). Only fractures occurring since the onset of SLE and unrelated to trauma were included, and the SDI score was modified to exclude osteoporotic fractures. Statistical analysis was by χ2 test, Fisher’s exact test, and binary logistic regression.
Results: 242 patients were studied, median age 39.9 years (range 18 to 80), median disease duration 7.0 years (range 0 to 42). Of these, 123 (50.8%) had reduced BMD (T score <−1.0) and 25 (10.3%) were in the osteoporotic range (T score <–2.5). Fragility fractures had occurred in 22 patients (9.1%) since diagnosis of SLE. Of these, two (9.1%) had normal BMD and 20 (90.9%) had reduced BMD, while seven (31.8%) were within the osteoporotic range. Non-Afro-Caribbean race and exposure to prednisolone >10 mg daily were significantly associated with reduced BMD, while age and menopause were associated with osteoporosis. The risk factors for fractures were reduced BMD and age.
Conclusions: Reduced BMD, osteoporosis, and fragility fractures appear to be prevalent in patients with SLE. Steroids were not an independent risk factor for fractures, although their effect could be mediated through reduced bone mineral density.
- BMD, bone mineral density
- SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index
- SLE, systemic lupus erythematosus