Pamidronate treatment of children with moderate-to-severe osteogenesis imperfecta: a note of caution.

BACKGROUND/AIMS: Bisphosphonates have been reported to decrease fractures related to osteogenesis imperfecta (OI). We assessed the efficacy and long-term safety of pamidronate therapy in patients with moderate-to-severe OI.

METHODS

We conducted an open-label uncontrolled study in 14 boys and 13 girls whose mean age was 6.8 years at baseline. Intravenous pamidronate, 1 mg/kg/day, was given for 3 consecutive days every 4 months for 2-6 years, with physical therapy and orthopedic surgery as appropriate. Mobility score, fracture rate, height, bone mineral density (BMD) and bone healing were evaluated throughout follow-up.

RESULTS

In 24 (89%) patients, the fracture rate decreased to <or=2/year and/or the mobility score improved. The remaining 3 (11%) patients continued to experience more than 2 fractures per year with mobility scores <2 despite significant BMD gains. Delayed radiographic fracture healing (>6 months) occurred in 8 (29.6%) patients; their BMD gains, baseline age and treatment duration were not significantly different from those in the other patients. Tolerance was good.

CONCLUSION

Pamidronate with physiotherapy and orthopedic management improved outcomes without delaying fracture healing in 19 (70%) of 27 patients. Delayed fracture healing occurred in 8/27 patients. Pamidronate should be reserved for severe OI with multiple fractures and/or flattened vertebras.