Risk factors for postoperative delirium after elective major abdominal surgery in elderly patients: A cohort study.

•The increasing number of elderly patients requires new methods to prevent postoperative delirium.•Identification of the patients who are most at risk for developing delirium is therefore imperative.•Risk factors for delirium are renal or cognitive impairment, ASA≥3, being an active smoker, ICU admission and erythrocyte transfusion.•Prehabilitation has a protective effect, however may not be worthwhile prior to endovascular aortic repair.•Future prehabilitation programs on delirium prevention should incorporate smoking cessation and haemoglobin optimisation.