Prevalence and predictive factors of osteoporosis in Thai systemic sclerosis

Systemic sclerosis (SSc) is recognized as a chronic inflammatory disease and several SSc-associated factors may increase the risk of osteoporosis and its related fractures. To determine the prevalence and predictive factors of osteoporosis in Thai SSc, a cross-sectional study was designed in adult SSc patients at Scleroderma clinic, Khon Kaen University Hospital. The prevalence of osteoporosis with the 95% confidence interval (CI) were determined and the odds ratio (OR) with 95%CI were assessed the clinical association with osteoporosis. A total of 205 SSc patients were recruited with the female to male ratio of 2.7:1. The majority of cases were diffuse SSc subset (83.4%) with a disease duration < 5 years (62.9%). The overall prevalence of osteoporosis was 29.3% (95%CI 23.1-36.0). After an age adjusted analysis, the respective prevalence of osteoporosis at lumbar spine (LS) in women and men was 26.3% and 10%, while the prevalence of osteoporosis at the femoral neck (FN) in women and men was 11% and 2.1%. Low BMI (≤ 18.5 kg/m²) and menopause were associated with osteoporosis at both the LS and FN. Using multivariate analysis, low BMI and menopause were associated with osteoporosis at LS (OR 7.78 and 5.32, respectively), while low BMI was also associated with osteoporosis at LS in pre-menopausal women. In conclusion, the prevalence of osteoporosis in Thai SSc was 29.3%. Osteoporosis at the LS is more common than FN in both men and women. Low BMI was associated with osteoporosis in overall SSc and pre-menopausal women, while only menopause was associated with osteoporosis at the FN.