Objectives: Treatment with pamidronate improves the clinical course in children with osteogenesis imperfecta (OI), but theoretically might affect longitudinal growth. In this study we analyzed growth during cyclical intravenous pamidronate treatment in children and adolescents (age.04-15.6 years at baseline) with moderate to severe forms of OI types I, III, and IV.
Methods: The effect of 1 year of pamidronate treatment on height and weight was analyzed in 116 patients (OI-I, N = 29; OI-III, N = 42; OI-IV, N = 45). The results of 4 years of therapy were evaluated in 41 children (OI-I, N = 12; OI-III, N = 14; OI-IV, N = 15).
Results: Baseline height was low for age in all OI types. After 1 year of pamidronate therapy, height z scores had increased significantly in OI-III (by 0.3 +/- 0.8, mean +/- standard deviation; P =.04) and did not change in OI-I and OI-IV. Weight z scores increased significantly in OI-I (by 0.2 +/- 0.4, P =.01). After 4 years of pamidronate therapy, mean height z scores increased significantly in OI-IV (by 0.41 +/- 0.71, P =.04), whereas nonsignificant trends to increase were found for OI-I and OI-III. When height was expressed as a percentage of the result expected for untreated patients with the same OI type, long-term pamidronate therapy was associated with a significant height gain in all 3 OI types (P <.001). Eight patients who reached final height after 3.0 +/- 1.0 years of treatment were taller on average than expected for untreated patients (P =.04).
Conclusions: Four years of cyclical intravenous pamidronate treatment led to a significant height gain in moderately to severely affected OI patients.