New aspects of delirium in elderly patients with critical limb ischemia

The primary objective was to identify possible risk factors for delirium in patients with critical limb ischemia undergoing surgery. The secondary objective was to study the effect of delirium on complications, the length of hospital stay, health care costs, and mortality.

All patients 65 years or older with critical limb ischemia undergoing surgery from February 2013 to July 2014 at Amphia Hospital, were included and followed up until December 31, 2014. Delirium was scored using the Delirium Observation Screening Scale (DOSS). Perioperative risk factors (age, comorbidity, factors of frailty, operation type, hemoglobulin, and transfusion) were collected and analyzed using logistic regression. Secondary outcomes were the number of complications, total hospital stay, extra health care costs per delirium, and mortality within 3 months and 6 months of surgery.

We included 92 patients with critical limb ischemia undergoing surgery. Twenty-nine (32%) patients developed a delirium during admission, of whom 17 (59%) developed delirium preoperatively. After multivariable analysis, only diabetes mellitus (odds ratio [OR] =6.23; 95% confidence interval [CI]: 1.11-52.2; P=0.035) and Short Nutritional Assessment Questionnaire for Residential Care (SNAQ-RC) ≥3 (OR =5.55; 95% CI: 1.07-42.0; P=0.039) was significantly associated with the onset of delirium. Delirium was associated with longer hospital stay (P=0.001), increased health care costs, and higher mortality after 6 months (P<0.001).

Delirium is a common adverse event in patients with critical limb ischemia undergoing surgery with devastating outcome in the long term. Most patients developed delirium preoperatively, which indicates the need for early recognition and preventive strategies in the preoperative period. This study identified undernourishment and diabetes mellitus as independent risk factors for delirium.