Mini-Cog to predict postoperative mortality in geriatric elective surgical patients under general anesthesia: a prospective cohort study

BACKGROUND: The aim of this study was to examine whether preoperative Mini-Cog testing can predict postoperative mortality in geriatric patients undergoing general surgery. METHODS: The study enrolled elderly patients (at least 65 years of age) scheduled to receive general surgery under general anesthesia between October 2015 and December 2017. Mini-Cog scores ≤2 were considered abnormal and indicative of probable cognitive impairment. All-cause mortality at one-year was compared between patients with normal or abnormal preoperative Mini-Cog scores. RESULTS: A total of 551 patients (333 women) were included in the study with a mean age of 71 years (SD, 7), and 183 (33.2%) patients had preoperative Mini-Cog scores ≤2. The one-year all-cause mortality rate was 18.0% for the study population, and was significantly higher in the cognitive impairment group (24.0%) than the normal group (15.0%, P=0.009). Kaplan-Meier survival analysis revealed significantly higher one-year mortality among those with cognitive impairment (log-rank, P=0.008), even after adjustment for confounding factors (hazards ratio 1.6, 95% CI: 1.1 to 2.4; P=0.03). The two groups did not differ significantly in the incidence of postoperative complications (13.0% vs. 13.7%, P=0.894), length of hospital stay (10.2±7.4 vs. 10.4±8.3 days, P=0.136), or the need of Intensive Care Unit stay after surgery (14.8% vs. 11.7%, P=0.308). CONCLUSIONS: Mini-Cog can be used to identify geriatric patients at risk of increased one-year mortality following elective surgery.