Comparison of the effects of alendronate and risedronate on bone mineral density and bone turnover markers in postmenopausal osteoporosis

The aim of the study was to compare the effects of once-weekly alendronate sodium and daily risedronate sodium treatment on bone mineral density (BMD) and bone turnover markers in postmenopausal osteoporotic subjects. For this purpose, 50 patients were included in this study and randomly classified into two groups. Group I (n=25) received risedronate (5 mg/day) and group II (n=25) received alendronate Na (70 mg/week). The study duration was limited to 12 months. The efficacy of the treatment was evaluated by BMD measurements at spine and hip at 6th and 12th months of the treatment, as well as by the measurement of bone turnover markers such as serum osteocalcin (OC), bone-specific alkaline phosphatase (BASP), urine deoxypyridinoline (DPD) and calcium/creatine ratio in 24-h urine at 1st, 3rd, 6th and 12th months. The evaluation of the changes in BMD in all regions revealed a significant increase in BMD in both groups compared to baseline values except for spine (L2–L4) in alendronate group at 6th and 12th month and femoral neck in risedronate group at 6th month. However, the difference in percentage increase in BMD measurements was not statistically significant between the two groups at 6th and 12th months. In both groups, serum OC, BSAP and urine DPD were found to be significantly attenuated at 1st month of the treatment period, and continued to be lowered throughout the 3rd, 6th and 12th months (P<0.05). However, there was no statistically-significant difference between both groups of patients (P>0.05). In conclusion, our results suggest that both treatment protocols provide treatment options of similar efficiencyfor postmenopausal osteoporosis, and have almost-similar effects in enhancing the BMD and in slowing the bone turnover. Risedronate seems to havea more potent effect in the spinal region than that of alendronate, although this potency was not statistically significant.