In these studies, the following factors are identified as independent predictors for the development of delirium: older age (>70 years) [11,27,30], lower intraoperative Hb levels [30], excessive bleeding during surgery with transfusions [30,31], operation time more than 7 to 10 h [24], high preoperative albumin values [25], postoperative insomnia [25], history of smoking [25], excessive alcohol consumption [12], time to ambulation after surgery [27], gender [32], postoperative pain control [32], and sedation period [26]. The gene discussed is GSTM1; the disease is delirium.