Efficacy of alendronate in the treatment of low bone density in the pediatric and young adult population.

Background: Pediatric osteoporosis is uncommon but can result in painful and debilitating insufficiency fractures. Treatment options for osteoporosis in children are few. Bisphosphonate therapy for children has not been approved by the Food and Drug Administration (FDA) in the United States, but its use in that population has been increasing. Randomized controlled studies have not been done because of the small subject pool and the difficulty in randomizing a child with an insufficiency fracture to a placebo arm of a study. This retrospective case-control study of a population of children with primarily neuromuscular disease was done to review changes in bone mineral density as reflected by dual x-ray absorptiometry (DXA) scanning.

Methods: Medical records and DXA scans were screened to identify children with low bone density who had been treated with alendronate as well as similar control subjects with low bone density for their age who had not received alendronate. Medication acquisition was confirmed by refill records, and cumulative exposure was calculated. Interval DXA scans were reviewed to correlate bone mineral density change in grams per square centimeter as well as the percent change and percent change over time for both alendronate-treated and control subjects.

Results: Twenty-eight alendronate-treated subjects and thirty control subjects met the inclusion criteria. No significant improvement in bone mineral density was seen in the alendronate-treated subjects as compared with the control subjects. Some patients in both groups exhibited marked improvement, with improvement of >31% seen only in the alendronate-treated subjects.

Conclusions: Alendronate does not reliably improve bone density in children and young adults with primarily neuromuscular disease and without osteogenesis imperfecta. Individual patients treated with bisphosphonates must be carefully followed to ensure medication compliance and appropriate response.