Significantly higher estimated 10-year probability of fracture in lupus patients with bone mineral density comparable to that of healthy individuals

Abstract

This study aimed at comparing the FRAX 10-year fracture risk between SLE patients and demographically- and anthropometrically matched healthy individuals. Consecutive SLE patients aged ≥ 40 were analyzed for the FRAX 10-year probability of major osteoporotic and hip fractures and their risk was compared with healthy controls matched for age, gender and body mass index. Potential determinants associated with higher 10-year fracture probability in the SLE patients were studied by regression models. Ninety subjects (45 SLE patients and 45 healthy controls) were studied. While the bone mineral density (BMD) of the lumbar spine and dominant hip was comparable between the two groups, the FRAX 10-year probability of major and hip fractures was significantly higher in SLE patients. Significantly more SLE patients had high 10-year fracture risk as defined by the National Osteoporosis Foundation compared with healthy controls (16 vs. 2 %, p = 0.026). After controlling for glucocorticoid use and premature menopause which were significant univariate risk factors, the difference in the 10-year fracture risk became insignificant. Amongst SLE patients, increasing age, lower hip BMD and cumulative glucocorticoid dose independently predicted higher 10-year major fracture risk while higher anti-dsDNA level independently predicted higher hip fracture risk in addition to age and lower hip BMD. Chronic glucocorticoid use and premature menopause led to higher 10-year probability of major osteoporotic and hip fractures in SLE patients compared with their healthy counterparts although their BMD was comparable. Advanced age, lower hip BMD, cumulative glucocorticoid and higher anti-dsDNA level independently predicted higher 10-year fracture risk amongst SLE patients.