Apolipoprotein E e4 allele increases the risk of early postoperative delirium in older patients undergoing noncardiac surgery.
BACKGROUND
Whether patients who subsequently develop early postoperative delirium have a genetic predisposition that renders them at risk for postoperative delirium has not been determined.


METHODS
The authors conducted a nested cohort study to include patients aged > or = 65 yr who were scheduled to undergo major noncardiac surgery requiring anesthesia. A structured interview was conducted preoperatively and for the first 2 days postoperatively to determine the presence of delirium, defined using the Confusion Assessment Method. Blood was drawn for measurement of the apolipoprotein genotypes. Bivariate tests of association were conducted between delirium and apolipoprotein genotypes and other potentially important risk factors. Variables that had significant bivariate association with postoperative delirium were entered in a forward multivariable logistic regression model.


RESULTS
Of the 190 patients studied, 15.3% developed delirium on both days 1 and 2 after surgery. Forty-six patients (24.2%) had at least one copy of the apolipoprotein e4 allele. The presence of one copy of the e4 allele was associated with an increased risk of early postoperative delirium (28.3% vs. 11.1%; P = 0.005). Even after adjusting for covariates, patients with one copy of the e4 allele were still more likely to have an increased risk of early postoperative delirium (odds ratio, 3.64; 95% confidence interval, 1.51-8.77) compared with those without the e4 allele.


CONCLUSIONS
Apolipoprotein e4 carrier status was associated with an increased risk for early postoperative delirium after controlling for known demographic and clinical risk factors. These results suggest that genetic predisposition plays a role and may interact with anesthetic/surgical factors contributing to the development of early postoperative delirium.
Leung
Jacqueline M
JM
Anesthesia and Perioperative Care, University of California, San Francisco, California 94143-0648, USA. leungj@anesthesia.ucsf.edu
Sands
Laura P
LP
Wang
Yun
Y
Poon
Annie
A
Kwok
Pui-yan
PY
Kane
John P
JP
Pullinger
Clive R
CR
D000368:Aged; D000483:Alleles; D053327:Apolipoprotein E4 / Q000235:genetics*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003693:Delirium / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D015994:Incidence; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology / Q000523:psychology*; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000523:psychology*; D013997:Time Factors
D053327:Apolipoprotein E4