The relationship between serum cobalamin, folic acid, and homocysteine and the risk of post-cardiac surgery delirium.

It has been reported that cobalamin and folate deficiency is related to delirium in persons with dementia. We evaluated the association of admission serum levels of cobalamin, folic acid, and homocysteine with the occurrence of acute delirium after coronary artery bypass surgery. In this prospective cohort study, serum levels of cobalamin, folic acid, and homocysteine were measured for 296 patients upon admission. Delirium was defined by the confusion assessment method for the intensive care unit. Postoperative delirium was detected in 23% (n=68) of patients. Cobalamin deficiency, folate deficiency, and hyperhomocysteinemia were observed in 29% (n=86), 6% (n=18), and 68% (n=200) of patients, respectively. The mean ± SD serum levels of folic acid were 10.77±5.39 ng/mL and 12.86±6.51 ng/mL in delirium and non-delirium patients, respectively (=0.008). The median (interquartile range [IQR]) serum levels of cobalamin were 280 (216-351) and 247 (195.5-336) in delirium and non-delirium patients, respectively (=0.09). The median (IQR) serum levels of homocysteine were 18.5 (14.5-22.1) µmol/L and 17.33 (14.2-23.2) µmol/L in delirium and non-delirium patients, respectively (=0.94). Multivariate regression analysis adjusted by other risk factors indicated that serum homocysteine, folate, and cobalamin levels had no association with the occurrence of delirium. There was no relationship between the preoperative levels of cobalamin, folate, and homocysteine, and acute occurrence of delirium observed after cardiac surgery.