One-year mortality after hip fracture in older individuals: the effects of delirium and dementia

Background Delirium is common in older hip fracture patients, yet its association with mortality after hip fracture remains uncertain. This study aimed to determine whether delirium was associated with all-cause one-year mortality after hip fracture in older patients and whether the effect of delirium was independent of dementia status. Method A retrospective analysis of linked hospitalisation and mortality data for patients aged ≥65 years with a hip fracture during 1 January 2010 to 30 June 2014 in New South Wales, Australia. The association between delirium and mortality after a hip fracture was assessed using Cox proportional hazard regression. Results There were 4,065 (14.6%) of 27,888 hip fracture hospitalisations identified with delirium during hospitalisation. Individuals with delirium had a higher age-adjusted rate of all-cause one-year mortality after hip fracture compared to individuals without delirium (35.3% versus 23.9%). After adjusting for covariates, the risk of all-cause mortality was increased at one-year post-admission for older individuals compared to those aged 65-69 years, for individuals with multiple comorbidities, dementia (Hazard Ratio (HR): 1.14; 95%CI:1.08-1.20), delirium (HR: 1.19; 95%CI:1.12-1.26), and who had an Intensive Care Unit admission (HR: 1.44; 95%CI:1.31-1.59). Comorbid delirium did not add additional mortality risk for individuals with a hip fracture who have dementia. Conclusions Delirium identified in hospital was associated with all-cause one-year mortality after hip fracture in older Australians without dementia. As delirium is potentially preventable, better systematic assessment and documentation of a hip fracture patient's cognitive state is warranted to select the most effective strategies to prevent and manage delirium.