Bone Metabolism in a Large Cohort of Patients with Systemic Sclerosis

The aim of this study was to evaluate in a large size cohort of SSc patients bone mineral density (BMD) and to analyze its possible determinants. 106 consecutive outpatients affected by SSc were enrolled and completely evaluated for bone metabolism and SSc characteristics. For the statistical analysis, we preferred Z score to BMD or T score since the population was composed of patients of different ages and of both sexes. Mean neck Z score was significantly lower than 0. No significant differences were found for other sites. Female patients were shown to have a total femur and neck Z score significantly lower than 0 (p = 0.028 and p < 0.001, respectively). 13 % of patients had at least one morphometric non-clinical vertebral fracture. In univariate analysis, total femur Z score was lower in female (p = 0.050) and positively correlates with BMI (p = 0.001), neck Z score positively correlates with age (p = 0.016), and whole body Z score positively correlates with BMI (p < 0.001). No correlations were found for lumbar Z score. The multivariate analysis confirmed the positive correlation between BMI and total femur and whole body Z score and between age and neck femur Z score (p = 0.005, p < 0.001 and p = 0.040, respectively). Lung involvement was shown to correlate with a lower whole body Z score in multivariate analysis (p = 0.037). We found a modest risk of low BMD in patients with SSc and the important protective role of BMI. Patients with lung involvement showed lower whole body Z score.