Change in Bone Mineral Density of Filipino Patients with Osteogenesis Imperfecta after 6 Months of Pamidronate Therapy in a Tertiary Hospital in the Philippines

Mary Ann R. Abacan,1,2 Ryan Albert Leonard N. Boquiren,3 Imarzen V. Elepaño3
and Maria Melanie Liberty B. Alcausin1,2

1Section of Genetics, Department of Pediatrics, College of Medicine and
Philippine General Hospital University of the Philippines Manila
2Institute of Human Genetics, National Institutes of Health,
University of the Philippines Manila
3Department of Radiology, College of Medicine and
Philippine General Hospital, University of the Philippines Manila

 

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 givin time for osteoblasts to build bone. To date, there has been no local date 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-9 years and 9 months old at the Philippine General Hospital with moderate to severe osteogenesis imperfecta who have undergone six months of pamidronate infusions at 1mg/kg/dose monthly or a total dose of 6mg/kg. Chart review was done. Hand radiographs taken at baseline and after six 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 six months post-treatment with a mean difference of 0.053mm (CI -0.0112 to 0.117). However, the increase was not statistically significant (p value 0.0874) when analyzed using the paird t-test at a 95% confidence interval. No adverse events were noted and only one patient reported a fracture after starting therapy.

Conclusion. 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.

Key Words: osteogenesis imperfecta, bisphosphonate, bone mineral density