Mortality risk among older Australians hospitalised with hip fracture: a population-based matched cohort study

Reidar P. Lystad, Cate M. Cameron, Rebecca J. Mitchell

With an ageing population, the burden of hip fractures is expected to increase in the coming decades. Older individuals with hip fracture are more than 3.5 times more likely to die within 12 months compared to non-injured individuals. The main priority for reducing mortality should be prevention of hip fracture. The aim of this study is to quantify and describe the 12-month mortality of older persons presenting to hospitals in Australia with a hip fracture. Population-based matched cohort study using linked hospital and mortality data from four Australian states (New South Wales, Queensland, South Australia, and Tasmania). Individuals aged 65 years and older who had a hospital admission with a primary diagnosis of hip fracture in 2009 (n = 9748) and a matched comparison cohort of non-injured individual were selected from the electoral roll (n = 9748). The comparison group was matched 1:1 on age, sex, and postcode of residence. Adjusted mortality rate ratios (MRR) and attributable risk percent were calculated. Cox proportional hazard regression was used to examine the effect of risk factors on survival. The hip fracture cohort experienced significantly worse survival at the 12-month post-fracture hospitalisation (P < 0.0001). Individuals with hip fracture were more than 3.5 times more likely to die within 12 months compared to their non-injured counterparts (MRR 3.62 [95%CI 3.23-4.05]). Hip fracture was likely to be a contributory factor in 72% of mortality within 12 months after the index hospital admission. Excess mortality risk at 12 months was higher in males than that in females and in the 65-74-year age group. With an ageing population in Australia, the burden of hip fractures is expected to increase in the coming decades. Because incident hip fracture is the main predictor of subsequent mortality, the main priority for reducing excess mortality after hip fracture is primary and secondary prevention of hip fracture.