DKK3 and acute kidney injury: Patients with CI-AKI had a 3.8-fold higher pre-procedural DKK3/creatinine ratio than those without AKI after intravenous contrast media application (7.5 pg/mg [IQR 1.2–1392.0] vs. 2.0 pg/mg [IQR 0.9–174.0]; p = 0.047).