Impact of alendronate on quality of life in children with osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a debilitating clinical condition characterized by fragile bone and skeletal deformity. Over the past decade frequent reports have suggested that the cyclical administration of intravenous pamidronate has a positive impact on bone density and skeletal fractures; however, the impact of such therapy on the quality of life (QOL) has rarely been reported. Alendronate, an oral bisphosphonate, is widely used to treat osteoporosis. The purpose of this study was to evaluate the impact of daily alendronate on QOL and bone parameters in children with OI. A prospective double-blind crossover study was designed in which placebo was alternated with daily alendronate. Twenty children with types I, III, and IV OI were recruited. Seventeen patients completed the study. Markers of QOL were measured in children with type III and IV OI (n = 15) using total mobility (PEDI), self-care (WeeFIM), well-being, pain, and use of analgesic scores. After 1 year of alendronate therapy, vertebral bone mineral density (BMD) improved from a change in standard deviation score (z-scorc) of 0.89 ± 0.19 to -0.12 ± 0.14 after 1 year of placebo (P < 0.001). All QOL markers, except for mobility score, improved in response to alendronate therapy. Change in height z-score also improved in response to 1 year of alendronate therapy (0.41 ± 0.21 vs. -0.09 ± 0.11, P < 0.05). Alendronate therapy did not alter serum levels of calcium, osteocalcin, parathyroid hormone (PTH), 1, 5 (OH)₂ vitamin D, cholesterol, or urinary hydroxyproline or any other biochemical marker evaluated. Alendronate decreased by 56% urinary cross-linked N-telopeptide of type 1 collagen divided by urinary creatinine (uNTX/uCr). Daily alendronate therapy was well tolerated. Only two patients had mild gastrointestinal discomfort, responding to minor adjustments in alendronate intake. Daily alendronate therapy is safe and effective in improving QOL in children with OI.