Bone turnover and hip bone mineral density in patients with sarcoidosis

Sarcoidosis is a chronic inflammatory T-cell-driven disease that can also affect bone. We evaluated bone remodelling and bone mineral density (BMD) in patients with sarcoidosis and their dependency of disease-related and treatment-related factors.

In 124 patients BMD of the hip (DXA) and markers of bone resorption (ICTP) and formation (PINP) were evaluated. Furthermore a lateral DXA of the spine for morphometric assessment of vertebral deformities was performed in 87 patients. Potential predictors of bone markers, BMD and determinants of prevalent vertebral deformities were assessed using multiple and logistic regression analysis.

The population studied comprised untreated patients (n=51), patients that previously used glucocorticoids (n=31) and patients currently using glucocorticoids (n=42). In all these groups the age- and gender corrected Z-scores of the hip were normal, except in untreated patients, which revealed an increased Z-score at the trochanter (p = 0.004). In all but the patients currently on glucocorticoids the Z-scores for PINP and ICTP were increased (p < 0.05). In patients currently on glucocorticoids the Z-ICTP was also increased (p < 0.05), but the Z-PINP decreased (p < 0.01 compared to untreated patients). In 20.6% of patients one or more morphometric vertebral deformities were found.

Hip BMD is normal in patients with sarcoidosis, despite an increased bone turnover. This may imply that in sarcoidosis mechanisms are involved that compensate for the well-known effects of cytokines in inflammatory diseases on osteoclastogenesis and bone resorption. Nonetheless, vertebral deformities suggestive of fracture were found in a significant number of patients which indicates that patients with sarcoidosis still have a relevant fracture risk.