IL1B and delirium: Subgroup analysis revealed that CSF IL-1β was higher in patients with incident delirium (median 1.74 pg/ml; IQR 1.02–1.74) compared to prevalent delirium (0.84 pg/ml; 0.49–1.57) and those who never developed delirium (0.66 pg/ml; 0–1.02) (Kruskal–Wallis p = 0.03) (Table 2, Supplementary Fig. 1).