APOE and delirium: Repeating MR for these two proteins using more strictly independent pQTLs (r2 < 0.001), APOE did not show evidence for heterogeneity (Q test P = 0.37), while its causal effect on delirium remained significant (IVW MR β (s.e.)= −0.57 (0.03); P = 1.13 × 10−78).