Denosumab is an antiresorptive medication commonly used in the treatment of osteoporosis that works by slowing bone loss. This medication should not be delayed or interrupted without initiation of an alternative treatment (i.e. bisphosphonates) as studies have shown that this can lead to rapid bone loss, very high markers of bone turnover, and increased vertebral fracture (VF) risk. It is unknown how frequently dosing is delayed in practice settings and how best practices can ensure timely dosing. Our study aimed to (1) evaluate the frequency and causes of delayed denosumab doses at our institution and (2) compare the incidence of delayed doses before and after implementation of a new electronic ordering process.
We performed a retrospective chart audit for all patients receiving two or more denosumab doses at our institution between 1/1/16-8/11/18 and categorized those whose doses were >/=214 days (7 months) as delayed. We reviewed notes, imaging, and labs in a subset of this population to assess reasons for the delay. On 8/11/18, a new outpatient infusion center (OIC) therapy plan went into place. This plan bundled a one-year denosumab order (2 doses) with an automatic referral to the OIC along with physician reminders for renewal. We compared rates of delayed denosumab dosing before and after implementation of this new order process.
Between 1/1/16-8/11/18, 385 patients received 1295 doses of denosumab, with 160 (41.6%) receiving 193 instances of delayed doses. We reviewed the charts of 98 individuals who received 111 instances of late doses between 7/6/16-8/11/18. The most prevalent reasons for delays were: delays in follow-up by the patient (27.9%), delays in the provider placing an order for the drug and OIC referral simultaneously (27.9%), and delays in OIC scheduling (18%). During the 14 months after implementation of the new ordering process, 347 patients received 614 instances of denosumab, of which 123 (35.4%) received 128 instances of delayed dosing. This is a relative decrease of 17.5% (p=0.09) for the proportion of patients with a late dose.
Nearly half of the patients on denosumab in our hospital received delayed denosumab dosing. Delays were often due to a lack of coordination between subsequent dose order placement and referral to the OIC. Our institution successfully implemented a bundled therapy plan to improve timely dosing. By March 2020, we expect to reassess the post-intervention group to further describe reasons for dosing delays. We also will compare rates of VFs associated with delayed denosumab dosing pre- and post-intervention periods.