Background:Postoperative delirium after elective surgery isfrequent and potentially serious. We sought to determine whetherthe use of statin medications was associated with a higher riskof postoperative delirium than other medications that do notalter microvascular autoregulation.
Methods: We conducted a retrospective cohort analysis of 284158 consecutive patients in Ontario aged 65 years and olderwho were admitted for elective surgery. We identified exposureto statins from outpatient pharmacy records before admission.We identified delirium by examining hospital records after surgery.
Results: About 7% (n = 19 501) of the patients were taking statins.Overall, 3195 patients experienced postoperative delirium; therate was significantly higher among patients taking statins(14 per 1000) than among those not taking statins (11 per 1000)(odds ratio [OR] 1.30, 95% confidence interval [CI] 1.15–1.47,p < 0.001). The increased risk of postoperative deliriumpersisted after we adjusted for multiple demographic, medicaland surgical factors (OR 1.28, 95% CI 1.12–1.46) and exceededthe increased risk of delirium associated with prolonging surgeryby 30 minutes (OR 1.20, 95% CI 1.19–1.21). The relativerisk associated with statin use was somewhat higher among patientswho had noncardiac surgery than among those who had cardiacsurgery (adjusted OR 1.33, 95% CI 1.16–1.53), and extendedto more complicated cases of delirium. We did not observe anincreased risk of delirium with 20 other cardiac or noncardiacmedications.
Interpretation: The use of statins is associated with an increasedrisk of postoperative delirium among elderly patients undergoingelective surgery.