Preoperative cognitive function and surgical outcomes under general anesthesia among older patients

To investigate whether preoperative cognitive impairment is associated with postoperative outcomes under general anesthesia.

This population-based cohort study utilized a nationwide database in South Korea. We included patients who underwent surgery under general anesthesia at the hospital between January 1, 2021, and December 31, 2021. The Korean Dementia Screening Questionnaire-Cognition (KDSQ-C), a tool designed for efficient dementia screening, was used to evaluate preoperative cognitive impairment. The KDSQ-C is administered during biennial National Health Insurance Service medical evaluations beginning at age 66 years.

This study included 108,158 older patients who underwent surgery under general anesthesia. In a multivariable Cox regression model, patients with KDSQ-C ≥ 6 had a 35 % higher risk of 90-day mortality than those with KDSQ-C of 0-5 (hazard ratio [HR]: 1.35, 95 % confidence interval [CI]: 1.15, 1.57; P < 0.001). Increased 90-day mortality was observed in the following KDSQ-C groups compared to those with a score of 0-5: KDSQ-C 11-15 (HR: 1.54, 95 % CI: 1.13, 2.11; P = 0.007), KDSQ-C 16-20 (HR: 1.98, 95 % CI: 1.31, 2.99; P = 0.001), KDSQ-C 21-25 (HR: 1.99, 95 % CI: 1.29, 2.57; P = 0.004), and KDSQ-C 26-30 (HR: 2.03, 95 % CI: 1.26, 3.28; P = 0.004). Similar results were found in the analyses of one-year all-cause mortality and postoperative complications.

Older patients with preoperative cognitive impairment undergoing general anesthesia have higher mortality and morbidity rates, particularly in patients with KDSQ-C scores ≥11.