Bone Abstracts

Background: Osteoporosis in children with osteogenesis imperfecta (OI) type 1 and acute lymphoblastic leukaemia (ALL) is characterised by high bone turnover. However the ability of spontaneous healing and reshaping of bone is retained in ALL even in the absence of bisphosphonate (BP) therapy, but impaired in OI.

Aim: To compare the response to BP therapy in children with ALL and OI.

Methods: Retrospective case note review of children with ALL and OI type 1 (2008–2013) managed at a single tertiary centre. Clinical data and dual energy x-ray absorptiometry (DXA) results were collected at baseline and following first year of intravenous BP therapy.

Results: Ten patients (seven males) with ALL were compared to 12 patients (seven males) with OI type 1. Four of ten and 5/12 received zoledronic acid in ALL and OI respectively and the others received pamidronate. The median age at start of BP treatment for ALL and OI groups were (9.65 vs 10.27 years, P=0.86). The median height SDS of OI group was significantly lower compared to ALL group at the start of treatment (−1.38 vs 0.29, P=0.001). Growth during therapy (Δ height SDS) was not different between ALL and OI groups (−0.28 vs 0.045, P=0.49).

Compared to baseline, the lumbar spine bone mineral apparent density (LSBMAD) z-scores improved significantly in both groups (ALL: −2.45(range −3.6 to −0.90) to −0.45 (range −2.5 to 0.5), P=0.005; OI: −2.70 (range −4.20 to −0.29) to −1.1 (range −2.15 to 1.17), P=0.003)). The 1-year change in LSBMAD z-score during treatment was similar between groups (ALL 1.34 vs OI 1.64, P=0.92). However, at the end of 1 year of treatment the median LSBMAD z-score in ALL patients (−0.45) was not different from normal (zero), but that for OI was significantly lower than normal (−1.1, P=0.010).

Conclusion: LSBMAD improvement in ALL is comparable to that in children with type I OI. Although both groups responded similarly to BP treatment, LSBMAD was closer to normal in ALL patients after 1 year of therapy.

Disclosure: The authors declared no competing interests.