Bone Abstracts

Aim: To assess long term safety of low dose pamidronate therapy and the effects on pubertal growth spurt.

Methods: A retrospective study was conducted in 36 girls and 21 boys whose mean age was 4.1±3.6 years at baseline. Intravenous pamidronate 3–4 mg/kg per year once daily therapy with 2–4 cycles/year for 0.5–15 years) was given with physical therapy and orthopedic surgery as appropriate. Mobility score, height, puberty and bone mineral density (BMD) was evaluated throught follow up (6.4±4.08 years).

Results: Puberty started before study inclusion in two patients and during the study 26 additional patients. Ten of these patients completed puberty during study. Overall lumbar spine BMD Z-score improved from −3.2±1.8 to −2.1±1.7 g/cm² (P: 0.0). The overall mobility score improved from 2.7±1.6 to 3.36±1.1 (P: 0.0) (13 of the patients were in infancy so they were not included in the mobilization scores). Mean height SDS was −2.12±2.6 at baseline and −2.0±2.3 at treatment completion (P: 0.7). Catch-up linear growth did not occur. Mean height SDS was −2.9±3.4 at the start of puberty and −3.6±4.7 at completion of puberty (P: 0.0). Although these patients did not catch up linear growth during puberty, their lumbar BMD Z-score increased from −2.1±1.5 to −0.9±0.95 during puberty (P: 0.3).

Conclusion: Our data suggests that cyclic low dose pamidronate therapy combined with physiotherapy and orthopedic procedures may improve the clinical manifestations as mobilization and bone mineral density. No significant catch up growth occurred during the study period and especially a decrease in height occurred during puberty. This decrease in linear growth can be related to the nature of the disease or to pamidronate therapy.