Incidence, prognostic factors and impact of postoperative delirium after major vascular surgery: A meta-analysis and systematic review.

Although postoperative delirium is a common complication and increases patient care needs, little is known about the predictors and outcomes of delirium in patients having vascular surgery. This review aimed to determine the incidence, prognostic factors and impact of postoperative delirium in vascular surgical patients. MEDLINE and EMBASE were systematically searched for articles published between January 2000 and January 2016 on delirium after vascular surgery. The primary outcome was the incidence of delirium. Secondary outcomes were contributing prognostic factors and impact of delirium. Study quality and risk of bias was assessed using the QUIPS tool for systematic reviews of prognostic studies, and MOOSE guidelines for reviews of observational studies. Quantitative analyses of extracted data were conducted using meta-analysis where possible to determine incidence of delirium and prognostic factors. A qualitative review of outcomes was performed. Fifteen articles were eligible for inclusion. Delirium incidence ranged between 5% and 39%. Meta-analysis found that patients with delirium were older than those without delirium (OR 3.6, p<0.001). Prognostic factors predicting delirium included increased age (OR 1.04, p<0.001), pre-existing cognitive impairment (OR 9.8, p=0.01), hypertension, pre-existing depression and open aortic surgery. Delirious patients remained in hospital 6 days longer ( p<0.001) and had more complications than patients without delirium. Data were limited on the impact of procedure complexity, endovascular compared to open surgery or type of anaesthetic. Postoperative delirium occurs frequently, resulting in major morbidity for vascular patients. Improved quality of prognostic studies may identify modifiable peri-operative factors to improve quality of care for vascular surgical patients.