Prevalence and Characteristics of Pre-Operative Delirium in Hip Fracture Patients

BACKGROUND: Delirium is a common complication of hip fracture and is associated with negative outcomes. Previous studies document risk factors for post-operative delirium but have frequently excluded patients with pre-operative delirium. OBJECTIVE: This study endeavours to document prevalence and risk factors for pre-operative delirium in hip fracture patients and compares risk factor profiles and outcomes between pre- and post-operative delirium. METHODS: 283 hip fracture patients were assessed pre-operatively with the Delirium Elderly At Risk (DEAR) instrument, Mini-Mental State Examination (MMSE), and Confusion Assessment Method (CAM). They were followed on post-operative days 1, 3, and 5 for the presence of delirium. Doses of opioids were recorded. Wait time to surgery, length of stay, and discharge site were noted. RESULTS: Delirium was present in 57.6% patients pre-operatively and 41.7% post-surgery. Not all patients (62%) with pre-operative delirium also had post-operative delirium. There was a considerable overlap in risk factors, with some differences. Wait time to surgery, number of comorbidities, and total pre-operative opioid and lorazepam doses were associated with pre- but not post-operative delirium. Negative outcomes were more closely associated with post-operative delirium. CONCLUSION: Delirium is common in pre-hip fracture surgery patients, and not all patients with pre-operative delirium go on to have post-operative delirium. Risk factor profiles are not identical, raising the possibility of identifying and intervening in patients at high risk of delirium pre-operatively.