Interpretation of BMD Scans in Patients Stopping Strontium Ranelate Treatment

“The oral administration of strontium ranelate causes a clinically significant overestimation of BMD because of the high attenuation of X-rays by strontium atoms in bone." GM Blake and I. Fogelman “performed a theoretical study to calculate the long-term effect of strontium treatment on BMD and establish the duration of past treatment for which the remaining bone strontium content (BSC) has a negligible effect on BMD.” “Estimates of the strontium BMD artefact after treatment has stopped were performed on the assumption that the BSC effect accounts for 75% of the total measured BMD change at 3 years.” “If 75% of the BMD changes are explained by BSC, in the average patient, 3-year treatment leads to a spine BMD artefact of 11.2%, decreasing to 3.8% 10 years after stopping treatment. The BMD artefacts at the total hip and femoral neck sites are smaller by factors of 0.65 and 0.53, respectively.” “On average, 6-month treatment is required for the spine BMD artefact to exceed 3%, the figure adopted as the maximum BMD change caused by bone strontium that has a negligible effect on scan interpretation.” The researchers concluded that “strontium ranelate treatment lasting for > 6 months can affect BMD measurements for many years afterward.” http://www.ncbi.nlm.nih.gov/pubmed/16939400 J Bone Miner Res. 2006 Sep;21(9):1417-24.