Prevalence of osteoporosis in patients with systemic lupus erythematosus: A multicenter comparative study of the World Health Organization and fracture risk assessment tool criteria

Osteoporosis and fracture are known complications of systemic lupus erythematosus (SLE). We assessed the prevalence and risk factors for osteoporosis in patients with SLE. A total of 155 female SLE patients were recruited retrospectively in 5 university hospitals. The bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry, and the fracture risk assessment tool (FRAX) for high-risk osteoporotic fractures was calculated with and without BMD. The mean age was 53.7 ± 6.8 years, and osteoporotic fractures were detected in 19/127 (15.0%) patients. The proportion of patients having a high-risk for osteoporotic fractures in the FRAX with and without BMD, and osteoporosis by the World Health Organization (WHO) criteria were 25 (16.1%), 24 (15.5%), and 51 (32.9%), respectively, and 48.0–68.6% of them were receiving treatment. On multivariate logistic analysis, nephritis (odds ratio [OR] 11.35) and cumulative dose of glucocorticoid (OR 1.1) were associated with high-risk by the FRAX with BMD, and low complement levels (OR 4.38), erythrocyte sedimentation rate (ESR) (OR 1.04), and cumulative dose of glucocorticoid (OR 1.05) were associated with osteoporosis by the WHO criteria in patients with SLE. Among Korean female patients with SLE, the proportion of patients having a high-risk of osteoporotic fractures by the FRAX tool was 15.5%–16.1% and the proportion of patients having osteoporosis by the WHO criteria was 32.9%. In SLE, nephritis, low level of complement, ESR, and cumulative dose of glucocorticoids may contribute to fracture risk.