Safety and Efficacy of Zoledronic Acid in children with Osteogenesis Imperfecta.

Objective: To evaluate the efficacy and safety of zoledronic acid in children with osteogenesis imperfecta (OI).

Study Design: Descriptive Study.

Place And Duration Of Study: National Institute of Child Health, Department of Endocrine and Diabetes, Karachi, Pakistan, from January 2011 to December 2020.

Methodology: Children, with OI registered for the treatment, were included. Zoledronic acid was given to them by intravenous infusion over 30 minutes with a dose of 0.05 mg/Kg/day for a median duration of 60 (24-96) months. To ensure safety, patients were kept for 24 hours after dose administration to monitor any short-term side effects. The patients were assessed after every 3-6 months for frequency of fracture, bone pain, and BMD.

Result: Out of 82 children [40 females (48.8%) and 42 males (51.2%)], 11 patients (13.4%) had fever and 2 patients (2.4%) had flu-like illness. No other side effects were observed. The annual fracture rate decreased overall from 2.8±1.5 to 0.2±0.5 (˂0.001) in both males (2.6±1.3 to 0.1±0.4) and females (3.1±1.7 to 0.2±0.6). Z-score on DEXA scan showed improvement in BMD overall (-3.9±2.0 to 2.2 ±1.7), in males (-3.7±1.9 to -2.1±1.7) and in females (4.1±2.1 to -2.3±1.8). There were no other long-term side effects like ocular problems, osteonecrosis of the jaw, and delayed healing of the fractures.

Conclusion: Zoledronate use in children is associated with minimal short-term and long-term side effects with a significant improvement in BMD and decline in fracture rate.

Key Words: Osteogenesis imperfecta (OI), Bisphosphonates (BPs), DEXA scan, Bone mineral density (BMD).