Incidence and risk factors of delirium after hip surgery

Objective: Postoperative delirium is common among elderly hip surgery patients. The objective of the current study was to determine the incidence of delirious states and to identify possible risk factors. Method: The sample consisted of 200 consecutive patients, age 60 years and older, who underwent hip surgery because of acute hip fracture or elective hip replacement. Patients were prospectively assessed preoperatively and on a daily basis postoperatively using the Confusion Assessment Method (CAM). Associations between risk factors and delirium were analysed by means of multiple logistic regression models. Results: 20.5% of the sample were diagnosed with postoperative delirium. Statistically significant risk factors for the development of delirium were higher age, lower preoperative cognitive test performance and severe physical comorbidity. Some other putative risk factors tended to be associated with postoperative delirium, but failed to reach statistical significance. Conclusions: The study confirmed a high incidence of delirium among hip surgery patients. Apart from established risk factors like old age, low cognitive test performance, and comorbidity, no other significant risk factors could be identified.