Strontium ranelate effect on bone mineral density is modified by previous bisphosphonate treatment

Abstract

The aim of this study was to evaluate the effect of strontium ranelate (SrR) on bone mineral density (BMD) and boneturnover markers after 1 year of treatment. Additionally, theeffect of SrR in bisphosphonate-naïve patients (BP-naïve)compared to patients previously treated with bisphosphonates (BP-prior) was analyzed. This retrospective study included482 postmenopausal women treated with SrR (2 g/day) for 1year in ten Argentine centers; 41 patients were excludeddue to insufficient data, while 441 were included. Participants were divided according to previous bisphosphonatetreatment in two groups: BP-naïve (n = 87) and BP-prior (n = 350). Data are expressed as mean ± SEM. After 1 year oftreatment with SrR the bone formation markers total alkaline phosphatase and osteocalcin were increased (p < 0.0001),while the bone resorption marker s-CTX was decreased (p =0.0579). Also increases in BMD at the lumbar spine (LS,3.73%), femoral neck (FN, 2.00%) and total hip (TH, 1.54%) [p < 0.0001] were observed. These increments were significant(p < 0.0001) both among BP-naïve and BP-prior patients. Interestingly, the change in BMD after 1 year of SrR treatmentwas higher in BP-naïve patients: LS: BP-naïve = 4.58 ± 0.62%; BP-prior = 3.45 ± 0.28% (p = 0.078). FN: BP-naïve = 2.79 ±0.56%; BP-prior = 2.13 ± 0.29% (p = 0.161). TH: BP-naïve = 3.01± 0.55%; BP-prior = 1.22 ± 0.27% (p = 0.0006). SrR treatmentincreased BMD and bone formation markers and decreaseda bone resorption marker in the whole group, with betterresponse in BP-naïve patients.