Risk factors for postoperative delirium in elderly patients after spinal fusion surgery

BACKGROUND: Postoperative delirium (POD) has an incidence rate of 9% to 41%. It is directly linked to decreasing cognitive function, increasing length of hospitalization and cost, as well as other complications and mortality. We aimed to assess the risk factors for POD among elderly patients by analyzing data from those who underwent spinal surgery. METHODS: This study included 446 patients aged 65 years or older who underwent spinal surgery at our institution between March 2013 and May 2018. Data were collected retrospectively from the patients’ electronic medical records, and logistic regression was used to identify the risk factors associated with POD. The diagnosis of POD was based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and was made through consultation with a psychiatrist during postoperative hospitalization and before discharge. RESULTS: Seventy-eight (78/446, 17.4%) patients were diagnosed with POD. The most relevant risk factor for POD was preoperative cognitive dysfunction (odds ratio [OR], 4.37; 95% confidence interval [CI], 1.60 to 11.93; P = 0.004), followed by emergency surgery (OR, 2.70; 95% CI, 1.27 to 5.74; P = 0.01), age (OR, 1.19; 95% CI, 1.13 to 1.26; P < 0.001), and anesthesia time (OR, 1.01; 95% CI 1.00 to 1.01; P = 0.002). CONCLUSIONS: Preoperative cognitive dysfunction, emergency surgery, age, and anesthesia time were factors that affected POD occurrence after spinal surgery. Patients with such associated factors may be at a higher risk for POD when undergoing spinal surgery, and hence, careful management may be necessary for these patients.