The serum levels of HMGB1 in patients with stage 3 AKI [6.49 [3.32–9.84] mg/dl] and stage 2 AKI [4.62 [2.74–6.6] mg/dl] were meaningfully higher than those with stage 1 AKI [3.46 [2.54–4.9] mg/dl], and serum HMGB1 levels in patients with stage 1 AKI were relatively higher than those without AKI [2.67 [1.74–3.63] mg/dl] (Table 1 and Supplementary Figure S1A). Here, HMGB1 is linked to acute kidney injury.