Zoledronic acid for hip fracture during initial hospitalization.

ABSTRACT

Inpatient zoledronic acid (IP-ZA) administered during the initial fracture hospitalization significantly improves the osteoporosis treatment rate. Clinical outcomes of IP-ZA after hip fracture remain uncertain. Here we report a cohort study that emulated a randomized controlled trial using real-world data and evaluated the risk of all-cause-mortality and radiologically confirmed subsequent new fractures among patients hospitalized for a hip fracture who had received IP-ZA as compared with propensity-matched controls. A total of 654 patients who had received IP-ZA and 6877 controls (for whom anti-osteoporosis treatment was indicated but no IP-ZA started during index hospitalization) were included in the study. The primary cohort comprised 652 IP-ZA patients (IP-ZA group) and 1926 matched controls (untreated group), with 71.7% female 92.1% White participants, with a mean age of 80.9 years. Cumulative all-cause mortality over the 24-month follow-up for the IP-ZA group was 12.3% and 20.7% for the untreated group (hazard ratio [HR], 0.62; 95% CI, 0.49-0.78, p < .001). A total of 585 (89.7%) patients in IP-ZA group received only a single dose of ZA during the 24 months, and the death rate of this single dose group was 13.3%, which was significantly lower than that of the untreated group (HR, 0.70; 95% CI, 0.55-0.89, p = .003). Rates of radiologically confirmed cumulative subsequent new vertebral fractures were 2.0% in the IP-ZA group and 5.4% in the untreated group (HR, 0.40; 95% CI, 0.22-0.71, p = .001). A similarly lower rate of new vertebral fractures was seen in the single dose subgroup (1.9% vs 5.4%; HR, 0.44; 95% 0.24-0.82, p = .008). IP-ZA, administered during the initial hospitalization for hip fracture, was associated with lower all-cause-mortality and risk of radiologically confirmed subsequent new vertebral fractures, and thus offers a mechanism to narrow the treatment gap in patients having sustained a hip fragility fracture.

Hip fracture is a serious complication of osteoporosis affecting approximately 300 000 Americans per year and is associated with a 20%-30% 1-year mortality rate. Most patients with hip fracture are elderly (average age, 80-81 years), with multiple underlying medical conditions and are often unable to timely attend post-hospitalization outpatient follow-up to initiate anti-osteoporosis treatment. As a result, only ~10% of post­hip fracture patients receive treatment for underlying osteoporosis. We have previously reported that zoledronic acid (ZA) administered during initial fracture hospitalization (IP-ZA) is safe and can effectively improve the osteoporosis treatment rate to 70%. The present study analyzed the clinical outcomes of 652 patients who had sustained hip fractures and were treated with IP-ZA and 1926 matched controls and revealed significantly reduced rates of all-cause mortality and vertebral compression fracture (VCF) during a 2-year follow-up period. Of note, nearly 90% of the treated patients received only a single dose of ZA (namely, IP-ZA), suggesting that, for most patients, the only opportunity to receive anti-osteoporosis treatment was during the index fracture hospitalization. Importantly, reduced mortality and VCF rates were readily seen in this single-dose group of patients. Our data suggest that IP-ZA is beneficial for osteoporotic hip fracture.