Effect of a single dose of zoledronic acid on lumbar spine bone mineral density in patients with osteoporosis: a retrospective cohort study

Purpose : Osteoporosis has become an important global public health issue. Zoledronic acid serves as an effective drug for treating osteoporosis. However, in the real world, this compound is not used as regularly as recommended in the guidelines. This study was conducted to explore the actual effects of a single dose of 5 mg of zoledronic acid. Patients and methods: This work involved the recruitment of 3274 patients who were diagnosed with osteoporosis during their hospitalization at the Healthcare and Endocrinology Department of Qilu Hospital (Qingdao), Shandong University, between January 2016 and March 2025. A total of 414 subjects were included in the final analysis, with 277 allotted to the zoledronic acid group and 137 to the observation group. We compared the changes and percentage changes in bone mineral density (BMD) between the groups from baseline. We established and analyzed the improvement rate, marked improvement rate, and deterioration rate of BMD and explored the influence of follow-up duration on the therapeutic effect of zoledronic acid. Independent sample t tests, multiple linear or logistic regression analyses, and restricted cubic splines were adopted for data analysis. Results: The difference in the change in lumbar-spine BMD from baseline between the zoledronic acid group and observation group was 0.048 (95% confidence interval [CI]: 0.042, 0.055) g/cm ² . This difference was 0.043 (95% CI: 0.036, 0.051) g/cm ² after adjustment for age, baseline BMD, body mass index, sex, and follow-up duration. The difference in the percentage change from baseline was 6.9% (95% CI: 5.9%, 7.8%) and reached 5.9% (95% CI: 4.9%, 6.9%) after adjustment for baseline characteristics. Compared with the observation group, the zoledronic acid treatment group presented an increased improvement rate, a marked improvement rate, and a decreased deterioration rate of BMD. A sensitivity analysis that included individuals with a follow-up duration of 11 to 14 months revealed similar outcomes. In our study, the follow-up duration, ranging from 10 months to 5 years, did not affect the therapeutic effect of zoledronic acid. Conclusion: In this real-world study, a single dose of zoledronic acid significantly improved lumbar spine BMD, effectively increased the improvement rate, and prevented the risk of BMD deterioration in osteoporosis patients. Moreover, this effect remained relatively stable for 5 years post-treatment.