Incidence and risk factors for postoperative cognitive dysfunction in older adults undergoing major noncardiac surgery: A prospective study

BACKGROUND & AIMS: Postoperative cognitive dysfunction (POCD) is a decline in cognitive function that occurs after surgery. The purpose of this study was to estimate the incidence and identify potential risk factors of POCD in older adults undergoing major noncardiac surgery. MATERIALS AND METHODS: A total of 69 patients aged 65 years or older undergoing major noncardiac surgery were enrolled. Patients’ cognitive function was assessed before and 3 months after surgery using a computerized neurocognitive battery. A nonsurgical control group of 54 older adults was recruited to adjust for learning effects from repeated administration of neurocognitive tests. Data about potential risk factors for POCD were collected before, during, and after surgery, including patient, medication, and surgery factors. The incidence of POCD was calculated using the Z-score method. A multivariable logistic regression model was used to identify risk factors for POCD. RESULTS: POCD was present in eleven patients (15.9%, 95% confidence interval [CI] = 7.3-24.6) 3 months after major noncardiac surgery. Carrying the apolipoprotein E4 (APOE4) genotype (odds ratio [OR] = 4.74, 95% CI = 1.09-22.19), using one or more highly anticholinergic or sedative-hypnotic drugs at home prior to surgery (OR = 5.64, 95% CI = 1.35-30.22), and receiving sevoflurane for anesthesia (OR = 6.43, 95% CI = 1.49-34.66) were associated with the development of POCD. CONCLUSIONS: POCD was observed in 15.9% of older adults after major noncardiac surgery. Risk factors for POCD in these patients were carrying the APOE4 genotype, using one or more highly anticholinergic or sedative-hypnotic drugs prior to surgery, and receiving sevoflurane for anesthesia.