Aim: Osteoporosis is a common chronic endocrine disorder causing low-trauma fractures. Sustained antiresorptive therapy is required for antifracture efficacy [1–3], yet long-term persistence after fracture remains poorly characterised. We examined 5-year persistence with oral bisphosphonates, zoledronic acid and denosumab; predictors of early non-persistence; and associations of first-year non-persistence with refracture and mortality.
Methods: From a population-based linked cohort of 2.3 million adults aged ≥50 years in New South Wales, Australia, we identified adults with an incident hospitalised low-trauma fracture during 2005–2018, no osteoporosis medication use in the prior 5 years, and initiation of an oral bisphosphonate, zoledronic acid or denosumab within 12 months. Grace periods were 60 days for oral bisphosphonates and denosumab and 6 months for zoledronic acid. Aalen–Johansen analyses estimated non-persistence, death before non-persistence, and remaining alive and persistent. Fine–Gray models examined predictors of non-persistence within 24 months; 12-month landmark analyses assessed 3-year refracture and mortality.
Results: The cohort included 25,570 women (mean age 77.1 years) and 7,485 men (79.1 years). At 1 year, the proportion alive and persistent was highest with zoledronic acid (women 91.2%; men 85.1%), followed by denosumab (69.4%; 56.5%) and oral bisphosphonates (54.0%; 48.2%). By 5 years, this had fallen to 5.9%–25.3%. Five-year non-persistence ranged from 63.9%–83.1% in women and 65.3%–76.5% in men; death before non-persistence was more frequent in men. First-year non-persistence was associated with 18–27% higher refracture risk and 15–20% higher mortality in women, and 23–24% and 20–32% higher risks, respectively, in men. Specialist rather than primary care prescribing predicted greater non-persistence, whereas dementia predicted lower non-persistence.
Conclusion: Long-term persistence after low-trauma fracture was poor across all therapies, and early advantages of longer-acting agents were not sustained. Early non-persistence identified patients at higher risk of refracture and death, highlighting the need to strengthen treatment continuity for secondary fracture prevention.