Prognostic factors of low bone mineral density in systemic sclerosis

Abstract

Objective: To analyse the results of bone densitometry in patients with systemic sclerosis (SSc), evaluating the prognostic factors of low bone mineral density (BMD) in fertile and postmenopausal patients, and comparing to a control healthy group.

Methods: Cross-sectional study analysing 61 female SSc patients, aged 25 to 51 years, who performed a bone densitometry using dual x-ray absorptiometry. BMD values (lumbar spine, femoral neck, Ward and trochanter) infertile and postmenopausal patients were compared according to SSc clinical variant (limited and diffuse), race, previous use of drugs (corticosteroids and cyclophosphamide) and bone mass index (BMI). These results were compared with 47 fertile and 60 postmenopausal healthy women; multivariate linear regression analysis was used to study the influence of the variables of interest in the BMD results.

Results: Twenty-seven SSc patients presented osteopenia and 14 densitometric osteoporosis. No statistical association was found between BMD values and SSc clinical variants, race and previous use of corticosteroids and cyclophosphamide, in the fertile and in the postmenopausal groups. Fertile SSc patients were paired by age and race with the control group, but BMI (p = 0.035) was significantly lower in the SSc group. BMD values of lumbar spine (p = 0.070, statistical trend), femoral neck (p = 0.003), Ward (p < 0.001) and trochanter (p = 0.003) were significantly lower in the SSc group. Postmenopausal SSc patients were paired by age and race with the control group, but BMI (p < 0.001) was also significantly lower in the SSc group. Age at menopause (p = 0.006) was also significantly lower and time from menopause (p < 0.001) was significantly higher in the SSc group. BMD values of femoral neck (p < 0.001), Ward (p < 0.001) and trochanter (p = 0.001) were significantly lower in the SSc group. Multivariate linear regression analysis showed that BMI was the main variable influencing BMD in the fertile and postmenopausal groups.

Conclusion: In the present study, BMD results in fertile and postmenopausal SSc patients were independent of the SSc clinical variants, race and previous use of corticosteroids and cyclophosphamide. A low BMD in appendicular sites was observed infertile and postmenopausal SSc patients when compared to a control healthy group, associated to a low BMI.