Aim: The aim of this study was to evaluate the effect of risedronate treatment on OPG, C-terminal cross-linking telopeptide of type 1 collagen (CTX), osteocalcin (OC), deoxypyridinoline (DPD), and to establish the correlation of OPG levels with other bone turnover markers.
Methods: Eighty postmenopausal osteoporotic patients were randomized into two groups. In the first group, 37 patients received 35 mg of risedronate once a week, and 600 mg of elementary calcium with 400 IU of vitamin D per day. In the second group, 34 patients received only 600 mg of elementary calcium with 400 IU of vitamin D per day. OPG, OC, CTX and DPD levels were measured at baseline, then at 1, 3 and 6 months of treatment.
Results: OPG levels were significantly reduced at 1 and 6 months of treatment in both the risedronate and control group (p<0.05, p<0.01, respectively), but no statistically significant difference was detected between the two groups (p>0.05). In the group treated with risedronate, a difference in CTX level was observed at 3 months of treatment, while a difference in DPD and OC levels were observed 6 months of treatment. The baseline OPG levels correlated with age, menopause duration and CTX levels. There was no correlation between OPG levels and the levels of the other markers.
Conclusion: Our results showed that using risedronate to treat postmenopausal osteoporosis causes no specific changes in OPG levels; thus, measurement of OPG levels as a marker may not be useful in the monitoring of bisphosphonate treatment.