This study investigated the risk factors for postoperative cognitive dysfunction (POCD) after major noncardiac surgery and its impact on mortality. A prospective longitudinal study of 1,064 patients aged 18 years or older found that POCD was present in 36.6% of young, 30.4% of middle-aged, and 41.4% of elderly patients at hospital discharge. At 3 months post-surgery, POCD prevalence was 5.7% in young, 5.6% in middle-aged, and 12.7% in elderly patients. Elderly patients had a significantly higher prevalence of POCD compared to their age-matched controls. Independent risk factors for POCD at 3 months included increasing age, lower educational level, a history of previous cerebral vascular accident with no residual impairment, and POCD at hospital discharge. Patients with POCD at hospital discharge were more likely to die within 3 months, and those with POCD at both hospital discharge and 3 months were more likely to die within the first year after surgery. The study found that cognitive dysfunction is common in all age groups at hospital discharge, but only the elderly are at significant risk for long-term cognitive problems. POCD was associated with increased mortality in the first year after surgery. The study also found that lower educational level was a risk factor for prolonged cognitive decline. Patients with preexisting brain dysfunction or a history of stroke were more likely to develop POCD. The study concluded that increasing age, lower educational level, a history of previous cerebral vascular accident without residual impairment, and POCD at hospital discharge were independent risk factors for cognitive decline at 3 months after surgery. The study highlights the importance of identifying and managing POCD in elderly patients to reduce mortality risk.This study investigated the risk factors for postoperative cognitive dysfunction (POCD) after major noncardiac surgery and its impact on mortality. A prospective longitudinal study of 1,064 patients aged 18 years or older found that POCD was present in 36.6% of young, 30.4% of middle-aged, and 41.4% of elderly patients at hospital discharge. At 3 months post-surgery, POCD prevalence was 5.7% in young, 5.6% in middle-aged, and 12.7% in elderly patients. Elderly patients had a significantly higher prevalence of POCD compared to their age-matched controls. Independent risk factors for POCD at 3 months included increasing age, lower educational level, a history of previous cerebral vascular accident with no residual impairment, and POCD at hospital discharge. Patients with POCD at hospital discharge were more likely to die within 3 months, and those with POCD at both hospital discharge and 3 months were more likely to die within the first year after surgery. The study found that cognitive dysfunction is common in all age groups at hospital discharge, but only the elderly are at significant risk for long-term cognitive problems. POCD was associated with increased mortality in the first year after surgery. The study also found that lower educational level was a risk factor for prolonged cognitive decline. Patients with preexisting brain dysfunction or a history of stroke were more likely to develop POCD. The study concluded that increasing age, lower educational level, a history of previous cerebral vascular accident without residual impairment, and POCD at hospital discharge were independent risk factors for cognitive decline at 3 months after surgery. The study highlights the importance of identifying and managing POCD in elderly patients to reduce mortality risk.