AKI in SCA. (A) Severity of AKI events among patients with SCA. AKI severity was stage 1 (serum creatinine rise 1.5-1.9 times baseline) in 73 of 135 (54%) AKI events, stage 2 (serum creatinine rise 2.0-2.9 times baseline) in 38 of 135 (28%) AKI events, and stage 3 (serum creatinine rise ≥3 times baseline, serum creatinine ≥4.0 mg/dL, or requiring hemodialysis) in 24 of 135 (18%) AKI events observed in patients with SCA during the follow-up period. (B) AKI risk by candidate gene variants. No association for AKI risk with APOL1 G1 and G2 risk variants or coinheritance of α-thalassemia was observed, whereas trends were observed for an association with HMOX1 rs743811 T risk allele and long GT tandem repeats in the promoter region of HMOX1. (C) CKD progression by AKI status. SCA patients with an AKI event (14/63, 22%) had more rapid CKD progression (defined as a 50% reduction in eGFR or requiring renal replacement therapy) compared with those without an AKI event (5/74, 7%). (D) CKD progression by AKI severity. Severity of AKI events was associated with more rapid progression of CKD in patients with SCA (stage 3: 5/15, 33%; stage 2: 7/22, 32%; stage 1: 2/26, 8%; no AKI: 5/74, 7%).