Plot of multivariable adjusted hazard ratios according to preoperative levels of fibroblast growth factor 23. (A) Mortality during follow-up. (B) Acute kidney injury. (C) Non-occlusive mesenteric ischaemia (NOMI). (D) In-hospital mortality. Solid lines represent the hazard ratios (HRs), and dashed lines the respective 95% confidence intervals. The median of fibroblast growth factor 23 (FGF23) (64 relative units (RU)/ml) was chosen as the reference value (HR =1). Data are adjusted for age, sex, mean arterial blood pressure, sinus rhythm, coronary artery disease, chronic heart failure, diabetes, serum creatinine and serum high-sensitivity C-reactive protein. Green areas represent the range of FGF23 with a HR <1, yellow areas with HR ≥1 and <1.5 and red areas with HR ≥1.5.