Bone turnover and the response to alendronate treatment in postmenopausal osteoporosis

This study investigated whether bone turnover influences the response to al endronate in women with postmenopausal osteoporosis. One hundred postmenopa usal osteoporotic women were randomized to receive either alendronate (10 m g/day) plus calcium (1000 mg/day) (n = 50) or calcium alone (n = 50). Verte bral and radial bone density, measured by DXA, and markers of bone turnover were assessed at baseline and after 1 and 2 years. At the end of treatment , alendronate users showed an increase of 5.0% and 2.3%, respectively, at t he lumbar spine and ultradistal radius; in the group treated only with calc ium, bone mineral density (BMD) decreased by 1.6% at the lumbar spine and 1 .3% at the ultradistal radius. The difference between the two groups was si gnificant (P < 0.001). The patients were divided into high (HT) or low (LT) bone turnover groups, as assessed by 24-hour whole body retention (WBR%) o f Tc-99m-methylene-diphosphonate. The response to alendronate treatment was greater in HT patients compared with LT patients. In fact, at the end of t he study period, BMD at the lumbar spine had increased by 7.9% in HT patien ts and by 3.0% in LT patients; the difference between the two groups was si gnificant (P < 0.001). No significant difference between the two groups was found for BMD at the ultradistal radius. In conclusion, the present study demonstrates that 2-year treatment with alendronate has highly positive eff ects on bone mass at both the lumbar spine and ultradistal radius. The incr ease in bone mass, especially at the axial level, is influenced by bone tur nover. Therefore, the evaluation of bone turnover may be useful in predicti ng the response to alendronate treatment.