Association between 3-word recall on the Mini-cog and postoperative delirium

Screening for cognitive impairment (CI) using tools such as the Mini-Cog has proven useful in identifying patients at high risk for adverse postoperative outcomes prior to surgery, including delirium. To date, no study has examined the independent associations of individual Mini-Cog components with surgical outcomes. To address this gap, we investigated the associations of the Clock Drawing Test (CDT) and 3-Word Recall with delirium and other adverse postoperative outcomes through employing a post-hoc analysis. Patients were recruited from preoperative clinics of Toronto Western Hospital and Mount Sinai Hospital, Toronto, Canada. We included 382 adults ≥65 years undergoing elective non-cardiac surgery. The Mini-Cog was administered to all patients 1–30 days before surgery and postoperative outcomes were collected 30 and 90 days following surgery. Delirium and other postoperative outcomes, including length of hospital stay, non-home discharge, readmission, all-cause complications, emergency room visits, mortality and composite adverse outcomes, were compared across CDT results (abnormal vs. normal) and 3-Word Recall performance (impaired recall <3 vs. perfect recall = 3) using univariable and multivariable analyses. A sensitivity analysis was also conducted using a stricter recall threshold (recall <2 vs. ≥2). Thirteen percent of participants screened positive for CI preoperatively with a total Mini-Cog score < 3. Twenty-three percent demonstrated an abnormal CDT result, while 37.2% scored <3 on the 3-Word Recall. Participants scoring <2 on recall (6.8%) had increased odds of delirium (OR = 14.06). No association was found between an abnormal CDT or scores <3 on the 3-Word Recall and delirium or other adverse postoperative outcomes. Impaired 3-Word Recall (<2) was linked to increased odds of postoperative delirium, representing a novel contribution to the literature. This stricter recall threshold may better capture the subtle vulnerabilities in cognitive reserve which can precipitate delirium. These exploratory, hypothesis-generating findings need further validation in larger, prospective cohorts.