Denosumab utilization among older adults in Ontario: patient characteristics, persistence with therapy, and return to therapy after an extended gap.
Osteoporos Int. 2019 Jul 17;: Authors: Ban JK, Hao BB, McCarthy L, Guilcher SJT, Cadarette SM
NTRODUCTION: The purpose of this study was to describe the characteristics of patients who initiated denosumab and estimate persistence with therapy. METHODS: We identified older adults (aged ≥ 66 years) in Ontario who initiated denosumab between 2012/02 and 2015/03 and followed them to 2016/03. Patient characteristics were summarized using medical and pharmacy claims in the year before starting denosumab and osteoporosis drug use considered since 1996/10. Persistence with denosumab and return after discontinuation (> 90-day gap) were estimated using Kaplan-Meier curves. Analyses were stratified by community and long-term care (LTC) residence. RESULTS: We identified 46,797 patients (monthly mean = 1263, SD = 187); 97% female, 13% LTC. Community-dwelling patients had a higher prevalence of bone mineral density testing (62% vs. 5%), yet were younger (mean age 78.5 vs. 86.6 years) and had lower prevalence of hip fractures (3% vs. 10%) compared to LTC patients. Eighty-two percent of patients had used osteoporosis medications in the past; 99% of whom took an oral bisphosphonate. Persistence was similar between community-dwelling and LTC patients: 59% persisted ≥ 2 years, 48% ≥ 3 years, and 38% ≥ 4 years, yet a larger proportion of LTC patients returned to denosumab after discontinuation (76% vs. 57%). CONCLUSIONS: Denosumab utilization is increasing at a steady rate in Ontario. However, persistence remains a concern given the highly reversible pharmacokinetic profile of denosumab that results in a rapid increased fracture risk following discontinuation. Over 80% of patients had a history of oral bisphosphonate therapy, which may persist in bone despite discontinuing denosumab. Consequently, better understanding of denosumab safety and effectiveness among real-world users is important. PMID: 31317248 [PubMed - as supplied by publisher]