<p><b>BACKGROUND</b>The relationship between
inflammation and
delirium remains to be determined. The purposes of this study were to investigate the
association between
serum interleukin-6 levels and the occurrence of
delirium in
elderly patients after major noncardiac
surgery .</p><p><b>
METHODS </b>A total of 338
elderly patients (60 years of age and over) undergoing major noncardiac
surgery were enrolled.
Blood samples were obtained before
anesthesia and in the first postoperative morning and
serum interleukin-6 concentrations were measured.
Delirium was assessed twice daily by the
confusion assessment
method for the
Intensive Care Unit during the first three postoperative days.
Survival analyses were performed to assess the relationship between the
serum IL-6 level and the occurrence of
postoperative delirium .</p><p><b>RESULTS</b>
Postoperative delirium occurred in 14.8% (50 of 338) of
patients . High
serum interleukin-6 levelsafter
surgery were significantly associated with increased
risk of the occurrence of
postoperative delirium (
hazard ratio 1.514, 95%
confidence interval 1.155-1.985, P = 0.003). Other independent predictors of
delirium included increasing age, poor preoperative
New York Heart Association classification , low preoperative Mini-Mental
State Examination score, and high total postoperative Visual Analogue Scale
pain score.
Patients who developed
delirium had a prolonged
hospital stay after
surgery .</p><p><b>CONCLUSIONS</b>
Delirium is a frequent complication in
elderly patients after noncardiac
surgery . High
serum interleukin-6 level after
surgery is associated with increased
risk of the occurrence of
postoperative delirium .</p>