AB114. Change in bone mineral density of patients with osteogenesis imperfecta after 6 months of pamidronate therapy in the philippine general hospital: a retrospective review

Background: Osteogenesis imperfecta is a heritable disorder due to a collagen gene mutation causing a structural abnormality leading to brittle bones and osteopenia. To address the osteopenia, intravenous bisphosphonates (pamidronate) act by temporarily halting the action of osteoclasts giving time for osteoblasts to build bone. To date, there has been no local data regarding the improvement in bone mineral density of Filipino patients with osteogenesis imperfecta following treatment.

Methods: This study is a retrospective review that included six patients aged 1 year and 10 months to 9 years and 9 months old at the Philippine General Hospital with moderate to severe osteogenesis imperfecta who have undergone 6 months of pamidronate infusions at 1 mg/kg/dose monthly or a total dose of 6 mg/kg. Chart review was done. Hand radiographs taken at baseline and after 6 months of therapy were reviewed by a radiologist who was blinded, to determine metacarpal indices.

Results: There was an increasing trend in the metacarpal index from baseline to 6 months post-treatment with a mean difference of 0.053 mm (CI, −0.0112 to 0.117). However, the increase was not statistically significant (P value 0.0874) when analyzed using the paired t-test at a 95% confidence interval. No adverse events were noted and only one patient reported a fracture after starting therapy.

Conclusions: Bisphosphonate infusions among the six pediatric patients with moderate to severe osteogenesis imperfecta are well tolerated and although the increase in the metacarpal index from baseline after six months of treatment is not statistically significant, the trend shows improvement of the osteopenia from baseline.

Keywords: Osteogenesis imperfecta; bisphosphonate; bone mineral density