This retrospective population-based cohort study used statewide linked administrative health data from New South Wales, Australia. Participants were adults aged 50 years or older with an incident low‑trauma fracture occurring between January 2011 and June 2019. The analysis included 132,268 individuals, of whom 63.7% (84,222) were female.
The primary objectives were to characterise prescribing patterns for osteoporosis medicines after an incident low‑trauma fracture and to identify predictors of timing of treatment initiation. Timing of initiation after the index fracture was categorised as early (within 12 months), late (within 1–3 years) or no initiation during the 3‑year follow‑up. Secondary analyses examined predictors of time to treatment initiation within 12 months using Fine–Gray competing‑risk regression to account for death as a competing event.
This was a retrospective cohort design using linked administrative datasets covering hospitalisations, prescriptions, and mortality. The primary outcome measures were patterns of prescribing and the timing of initiation over 3 years following the incident fracture. Predictors of initiation within 12 months were estimated with Fine–Gray competing‑risk regression, which provides subdistribution hazard ratios while accounting for the competing risk of death.
Across the full cohort of 132,268 people with incident low‑trauma fractures, 29,802 individuals (22.5%) initiated an osteoporosis medicine within the 3‑year observation period. The majority, 102,466 people (77.5%), remained untreated during follow‑up. These outcomes reflect substantial under‑treatment of patients after a fragility fracture in this population.
Initiation rates differed by sex. Among females (mean age 77.7 years, SD 10.1), 20.1% initiated therapy within 12 months, a further 7.0% initiated within 1–3 years, and 72.9% remained untreated over 3 years. Among males (mean age 77.2 years, SD 10.0), 10.8% initiated within 12 months, 3.7% within 1–3 years, and 85.6% remained untreated. These results indicate lower initiation rates in males compared with females and highlight an age group at elevated absolute fracture risk but with low rates of secondary prevention treatment.
After accounting for the competing risk of death, several factors were associated with a higher likelihood of treatment initiation within 12 months:
Factors associated with a lower likelihood of initiation included:
These predictors indicate that both fracture characteristics and broader health status and access factors influenced whether and when patients received pharmacological secondary prevention.
The study observed a clear temporal shift in the choice of osteoporosis therapy. Over the study period denosumab rapidly displaced oral bisphosphonates as the dominant pharmacologic therapy initiated after fracture. The changing prescribing mix underscores evolving clinical practice and has implications for long‑term management strategies, given differences in dosing, duration, and planning required for discontinuation or switching between agents.
A notable secondary finding was that nearly one in four individuals who were late initiators experienced a refracture before starting osteoporosis treatment. This highlights a clinically important consequence of delayed initiation and missed opportunities for secondary fracture prevention.
More than three‑quarters of adults aged 50 years and older with an incident low‑trauma fracture in this New South Wales cohort remained untreated with osteoporosis medicines within 3 years. Treatment initiation was strongly associated with fracture site (particularly hip and vertebral fractures) and inversely associated with multimorbidity burden, and initiation rates were lower among males and people in rural or regional areas. The rapid replacement of oral bisphosphonates by denosumab as the predominant therapy emphasises the need for careful long‑term treatment planning and monitoring.
These findings document substantial gaps in post‑fracture pharmacologic secondary prevention in a large population and support prioritising timely initiation of evidence‑based osteoporosis therapy after fragility fracture, improved identification and management pathways for high‑risk patients, and strategies to address disparities in treatment access and multimorbidity considerations.