In model 2, after adjusting for variables in model 1 plus other variables including AF, perioperative hypotension, LgNT-pro-BNP, GLU and WBC, perioperative urine pH 5.0–6.0 and 7.5–8.5 remained associated with increased risk of CA-AKI, the OR values were 1.86 (95% CI 1.25–2.82, P = 0.003) and 2.70 (95% CI 1.55–4.68, P < 0.001), respectively. Here, NPPB is linked to acute kidney injury.