Background/Purpose: Persistence and compliance with osteoporosis therapies is associated with significantly fewer vertebral, nonvertebral and hip fractures. A number of studies have examined medication-taking behavior with oral bisphosphonates and teriparatide, and the 1-year persistence rates have ranged from 39.9% to 56.7%. Limited real-world data are available regarding persistence and compliance with newer osteoporosis therapies, such as denosumab, a RANK ligand inhibitor administered every 6 months as a subcutaneous injection. The purpose of this study is to assess persistence and compliance among patients treated with denosumab in a large claims database in the U.S.

Methods: In this retrospective, observational cohort study, patients 18 years of age and older newly initiating denosumab between January 1, 2012 and March 31, 2012 were identified for inclusion from the MarketScan ResearchDatabases. The date of the denosumab claim was defined as the index date. Patients were required to have at least 24 months of pre-index continuous enrollment with medical and pharmacy benefits. Patients were also required to have at least 8 months of post-index continuous enrollment for the interim analysis and at least 12 months of post-index continuous enrollment for the final analysis. Patients with Paget’s disease of the bone, osteogenesis imperfecta, hypercalcemia, malignant cancer and metastasis, HIV, and patients receiving preventive treatment for risk of breast cancer or denosumab in the pre-index period were excluded from the study.  In the post-index period, patients with a cancer or metastasis diagnosis appearing prior to a medical claim for denosumab were also excluded. The current report contains results from the interim analysis. Persistence as indicated by continuous use of denosumab without a gap of 60 days or more between injections, medication coverage ratio (MCR) as the proportion of days covered by denosumab, switching to another osteoporosis therapy, and patients not returning for denosumab therapy were assessed during the 8-month follow-up period.

Results: 1,570 patients newly treated with denosumab (mean [SD] age: 69.6 [12.0] years; 98.2% female) were identified. In the pre-index period, an osteoporosis diagnosis as indicated by ICD-9-CM codes was identified in 76.1% of the patients, while 4.0% had a diagnosis code of osteopenia, 7.1% had a diagnosis code of renal insufficiency, and the mean (SD) Charlson Comorbidity Index score was 1.1 (1.5). Pre-index osteoporosis treatment was identified in 57.5% of the patients, and 17.6% had an osteoporosis-related fracture in the pre-index period. During the 8-month post-index period, 70.0% of patients were persistent with denosumab, 1.5% switched to another osteoporosis therapy, and 28.5% did not return for denosumab therapy. The mean (SD) MCR over 8 months was 89% (10%), with 67.4% of patients having an MCR greater than 80%.

Conclusion: Rates of persistence and compliance with denosumab observed in this study appear to be higher than those with other osteoporosis medications reported in previous studies. This study provides real-world evidence on denosumab utilization, and its high rates of persistence and compliance.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/medication-use-with-denosumab-prolia-in-a-large-claims-database-in-the-united-states/