Efficacy of Oral Alendronate Versus Zoledronic Acid on Postmenopausal Osteoporosis

Background: Osteoporosis is a common condition among postmenopausal women, and one of the main medications for treatment is bisphosphonate compounds. Objectives: The aim of this study was to investigate and compare the efficacy of the oral form (alendronate) with injectable form (zoledronic acid) of bisphosphonate compounds. Methods: This retrospective cohort study was carried out over three years (2010 to 2012) on patients referred to Physical Medicine Clinic of Tehran, Imam Reza Hospital, and two private rheumatology clinics in the cities of Gorgan and Shiraz, Iran. According to inclusion and exclusion criteria, 33 postmenopausal women were studied in each of the alendronate and zoledronic acid groups. Results: Mean age and T-score of femur and lumbar spine before treatment showed no significant difference between the two groups (P = 0.223, 0.321 and 0.953, respectively). After a year of treatment, the T-score had improved and this improvement was statistically significant in both groups; however this improvement was higher in zoledronic acid group (P = 0.019 for femur and P = 0.011 for spine). Conclusions: The injectable form of bisphosphonates (zoledronic acid) compared to oral form (alendronate) has more effect on improving osteoporosis and T-score of postmenopausal women.