Adherence with intravenous zoledronate and intravenous ibandronate in the United States medicare population

Abstract

Objective Our objective was to evaluate adherence among new users of zoledronate and IV ibandronate among U.S. Medicare enrollees. Methods We used data from the Medicare 5% random sample to evaluate new users of IV zoledronate and IV ibandronate with continuous Part A+B fee-for-service coverage. The outcome was adherence as quantified by the proportion of days covered (PDC), measured continuously and dichotomously (>= 80%). Follow-up time extended from 18–27 months for all individuals. Factors associated with low adherence with zoledronate were evaluated with logistic regression. Results We identified 775 new users of zoledronate and 846 new users of IV ibandronate. For both drugs, 30–48% of first infusions were given in an outpatient infusion center, not in a physician office. The mean PDC for zoledronate users was 82%, which was greater than the mean PDC for the IV Ibandronate users (58–62%, depending on time period, p < 0.0001). Approximately 30% of zoledronate users did not receive a second infusion. Factors associated with low adherence to zolendronate included older age and receipt of the first infusion in an outpatient infusion center rather than a physician’s office. Conclusions Less frequently dosed IV bisphosphonates have not resolved the problem of suboptimal adherence with prescription osteoporosis medications. Interventions continue to be warranted to improve long term adherence with osteoporosis treatments.

Use of Osteoporosis Medications after Hospitalization for Hip Fracture: A Cross-national Study

“…23–26 Both patients and health care providers may need a better understanding of benefits versus harms related to bisphosphonates. Lastly, there is a need to improve patient adherence to medication as also seen in other studies, 27 as higher medication adherence is associated with a lower risk of recurrent fracture. 28, 29 …”

Analysis of osteoporosis treatment patterns with bisphosphonates and outcomes among postmenopausal veterans

“…Curtis et al estimate real-world zoledronic acid adherence to be 20% greater than for IV ibandronate, which is dosed quarterly, and also higher than other studies reporting adherence to weekly or monthly oral bisphosphonates [56].…”

Adherence and preference of intravenous zoledronic acid for osteoporosis versus other bisphosphonates

“…All of them are observational studies. Overall adherence was assessed by Curtis et al ,22 who demonstrated that the mean proportion of days covered (PDC) was significantly greater for once-yearly intravenous zoledronic acid (82%, p<0.0001) compared with quarterly intravenous ibandronate (approximately 60%). Approximately 30% of zoledronate users did not receive a second infusion.…”

“…The study by Curtis et al 22 describes that one factor associated with adherence to intravenous annual infusion is receipt of the first infusion in an outpatient hospital-based infusion centre rather a physician’s office. As a practical matter, a key element of promoting adherence on an infrequent dose intravenous therapy requires ensuring that the patient is scheduled to repeat the infusion and remembers to return.…”