Patients with postoperative delirium have significantly worse preoperative short-term cognitive performance and significantly greater long-term cognitive decline, compared with patients without delirium, according to Sharon K. Inouye, MD, and her associates.
In a prospective cohort study of 560 patients aged 70 years and older, 134 patients were selected for the delirium group and 426 for the nondelirium group. The delirium group had a significantly greater decline (–1.03 points) at 1 month, compared with those without delirium (P = .003). After cognitive function had recovered at 2 months, there were no significant differences between groups (P = 0.99). After 2 months, both groups decline on average; however, the delirium group declined significantly more (–1.07) in adjusted mean scores at 36 months (P =.02).
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From baseline to 36 months, there was a significant change for the delirium group (–1.30, P less than .01) and no significant change for the group without delirium (–0.23, P = .30). Researchers noted that the effect of delirium remains undiminished after consecutive rehospitalizations, intercurrent illnesses, and major postoperative complications were controlled for.
The patients underwent major noncardiac surgery, such as total hip or knee replacement, open abdominal aortic aneurysm repair, colectomy, and lower-extremity arterial bypass.
“This study provides a novel presentation of the biphasic relationship of delirium and cognitive trajectory, both its well-recognized acute effects but also long-term effects,” the researchers wrote. “Our results suggest that after a period of initial recovery, patients with delirium experience a substantially accelerated trajectory of cognitive aging.”
Read the full study in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association (doi:10.1016/j.jalz.2016.03.005).