Cognitive Trajectories After Major Surgery in Older Adults and Factors Associated With Severe Decline

PURPOSE: (1) To describe cognitive trajectory patterns over 6 years after major surgery in older adults, and (2) To identify patient characteristics associated with severe cognitive decline. METHODS: Group-based semiparametric trajectory modeling was performed on longitudinal cognitive data from the SAGES study, which enrolled patients aged ≥ 70 years undergoing major elective noncardiac surgery. Participants received comprehensive neuropsychological testing prior to surgery and postoperatively every 6-12 months up to 72 months. The primary outcome was change in general cognitive performance score, a composite of neuropsychological tests, at each of 11 follow-up timepoints relative to baseline. Generalized linear models were used to assess the associations of pre-surgical patient characteristics and incidence of postoperative delirium with cognitive trajectory. RESULTS: Of 560 participants, 326 were women (58%) and the average age was 76.7 (standard deviation 5.2) years. They underwent orthopedic (81%), gastrointestinal (13%), and vascular surgeries (6%), and 24% experienced postoperative delirium. We found the 3-group cognitive trajectory model to be optimal, with the groups characterized as severe decline trajectory (SDT) (15% of the cohort), slight decline (59%), or stable (26%). Of pre-surgical factors, age (relative risk [RR]: 1.06, 95% confidence interval [CI] 1.03-1.10 per 1 year increase) and 3MS (Modified-Mini-Mental) score (RR 0.95, 95% CI 0.92-0.99 per one point increase) were significantly associated with SDT. Participants who developed delirium had over two-fold higher risk of SDT compared to those who did not (RR: 2.15, 95% CI: 1.35-3.42). CONCLUSIONS: Among older adults undergoing major surgery, 15% experienced severe cognitive decline over the ensuing 6 years, 59% experienced slight decline, and 26% remained stable. Older age, baseline cognitive impairment, and delirium were associated with severe decline, with delirium having the strongest association. Our findings provide valuable information for older patients considering major surgery and may help clinicians target interventions.