GSTM1 and delirium: Multivariate logistic regression analysis was carried out on the significant findings in univariate analysis and showed five clinical characteristics, namely, age > 75 years, history of stroke, preoperative Hb ≤ 100 g/L, preoperative PaO2 ≤ 60 mmHg, and time between admission to surgery > 3 days, were significant predictors of postoperative delirium (Table 2).