HealthDay News — Older patients who develop delirium after surgery are more likely to show signs of cognitive dysfunction one month later, according to a study published online May 28 in Anesthesiology.
Lori A. Daiello, Pharm.D., from the Alzheimer’s Disease and Memory Disorders Center at Rhode Island Hospital in Providence, and colleagues evaluated data from the Successful Aging after Elective Surgery study. Confusion assessment method-based interviews and chart review were used to evaluate postoperative delirium each hospital day after major noncardiac surgery.
The researchers found that just under one-quarter of participants (134 of 560) developed delirium during hospitalization. At one month, just less than half (47 percent) met the International Study of Postoperative Cognitive Dysfunction-defined threshold for postoperative cognitive dysfunction; however, this number decreased by two and six months (23 and 16 percent, respectively). There was poor agreement and correlation between delirium and postoperative cognitive dysfunction at each follow-up. For patients with a history of postoperative delirium, the relative risk for postoperative cognitive dysfunction was significantly elevated at one month (relative risk [RR], 1.34; 95 percent confidence interval [CI], 1.07 to 1.67) but not at two months (RR, 1.08; 95 percent CI, 0.72 to 1.64) or six months (RR, 1.21; 95 percent CI, 0.71 to 2.09).
“Postoperative delirium and postoperative cognitive dysfunction may be distinct manifestations of perioperative neurocognitive deficits,” the authors write.