Pamidronate preserves bone mass for at least 2 years following acute administration for pediatric burn injury

We have previously shown that pamidronate, when given within 10 days of burn injury, preserves lumbar spine bone mineral content from admission to discharge in 6-8 weeks and at 6 months increases both lumbar spine and total body bone mineral content (BMC) over placebo. We followed patients unblinded after 6 months every 3 months up to 2 years post-burn to see if the effects of pamidronate were sustained. Additionally, we assessed bone remodeling at 1 year post-burn by iliac crest bone biopsy. We enrolled 57 subjects who were initially randomized to pamidronate (n=32) and placebo (n=25). After 2 years, 21 subjects (pamidronate=8, placebo=13) remained. Analysis of bone densitometry by dual energy X-ray absorptiometry revealed an effect of both treatment (p<0.012 for total body BMC, p<0.001 for lumbar spine BMC, p<0.014 for lumbar spine bone area and p<0.003 for lumbar spine bone density (BMD)) and time (p<0.0003 on total body BMC, p<0.001 on lumbar spine BMC, p<0.001 on lumbar spine bone area, and no significant difference on lumbar spine BMD). There was no interaction between treatment and time. Results for bone histomorphometry revealed no effect of treatment on either static or dynamic parameters but did show an effect of time on osteoid area (p=0.004, surface p<0.001, and width, p<0.001). We conclude that acute administration of pamidronate resulted in sustained therapeutic effect on bone and that this type of administration may serve as a useful adjunct to other therapies in the preservation and augmentation of bone mass following severe burns.