Association of mild cognitive impairment and comorbid depression with postoperative delirium in patients undergoing knee/hip arthroplasty: a prospective cohort study

The study examined the relationship between mild cognitive impairment (MCI), depression, and postoperative delirium (POD) in 1,464 patients undergoing knee or hip surgery. The incidence of POD was 13.9% (203 patients). Patients with combined MCI and depression had 18.56 times higher risk of developing POD compared to patients without these conditions. These patients showed higher levels of T-tau and P-tau proteins in cerebrospinal fluid and lower levels of Aβ42. These biomarkers partially explained the relationship between MCI with depression and POD (17.9–49.9%). The developed predictive model achieved an accuracy of 0.884. Patients with POD had significantly lower three-year survival than patients without POD.