Comparison of the efficacy, adverse effects, and cost of zoledronic acid and denosumab in the treatment of osteoporosis

Injectable osteoporosis drugs are increasing in popularity due to their efficacy and convenient administration. In this retrospective comparison of the two available treatments, denosumab (Prolia®) and zoledronic acid (ZA, Reclast®), we aimed to determine and compare the efficacy and tolerability of denosumab and ZA. The charts of patients who received denosumab and ZA at Loyola Hospital were reviewed, and adverse events were noted. Of primary interest were myalgias, flu-like symptoms, back pain, and fractures. A questionnaire regarding the efficacy, tolerability, and treatment cost supplemented this chart review in a subset of study participants. Bone mineral density (BMD) changes, bone turnover markers, and questionnaire results were also compared. The study cohort consisted of 107 patients (51 denosumab, 56 ZA). The denosumab group had a greater mean increase in spine BMD at 1 year (0.060 g/cm2) than the ZA group (0.021 g/cm2; P = .04). The change in femur and spine BMD at 1 year were not significantly different between the 2 groups. The ZA group had a significantly greater incidence of mild flu-like symptoms (29% ZA group vs. 0% denosumab group; P = .04). The denosumab group had a higher mean increase in spine BMD, and the ZA group had a higher incidence of flu-like symptoms, but the study groups were statistically similar in terms of patient satisfaction. As denosumab is still a relatively new therapy, there were a limited number of patients with posttreatment data available for comparison. As more posttherapy data become available, it can be further investigated.