Bone Abstracts

We performed a prospective study on 440 young patients (aged 3–20 years), affected by various chronic diseases (cystic fibrosis; juvenile idiopathic arthritis; nephrotic syndrome; systemic lupus erythematosus; Duchenne muscular dystrophy; autoimmune hepatitis; transplants; etc.), with periodical bone mineral density (BMD) evaluations with DXA, for 3–14 years (7.8±6.2).

266 patients were on long-term treatment with glucocorticoids (GCs); among them, 140 stopped GC treatment and were followed for 3–5 years after GC withdrawal. BMD was measured at lumbar spine (LS) and on total body (TB); LS BMAD (g/cm³) was calculated. Z-scores were calculated with respect to a sex- and age-matched healthy Italian population.

Patients never treated with GCs had a higher BMD (TB +2.6%; LS +5.9%) than those (of same sex, age, pubertal status, and disease) who received GCs.

GCs mainly affected trabecular bone, independently of age and disease. GCs influenced bone mass differently in relation to disease and age at onset. The BMD reduction was related to GC cumulative dose (<10 g prednisone equivalent, −23%; 10–30 g, −40%; and >30 g, −68%). There was a significant correlation between BMAD Z-score vs cumulative GCs dose (r=−0.84, P<0.001). LS bone loss was higher during the first year on GCs (−16%), and was different in different diseases.

Regarding fragility fractures, 83 (31%) of the 266 patients who received GCs sustained at least one fracture, and 33 more than one. In total, 161 fractures (39 vertebral) were recorded. 21 (15%) of the 140 patients followed after GC withdrawal sustained new fractures (all peripheral). Thiry-three (18.9%) of the 174 patients never treated with GCs sustained fractures (all peripheral), only six of them having more than one fracture (P<0.01).

This prospective study demonstrates that GCs cause bone loss and fractures also in young patients, affecting normal bone accrual. The fracture rate (at any site) significantly increases during GCs treatment. Vertebral fractures were observed only in patients receiving GC treatment.