Patients randomized to tight glucose control were more likely to be diagnosed as being delirious than those assigned to routine glucose control ( 26 of 93 vs. 15 of 105 ; relative risk , 1.89 ; 95 % CI , 1.06 to 3.37 ; P = 0.03 ) , after adjusting for preoperative usage of calcium channel blocker and American Society of Anesthesiologist physical status .