A recently published randomised controlled trial (the Kompas trial) compared prehydration with sodium bicarbonate solution with no prehydration in patients with chronic kidney disease (eGFR 30-60 ml/min per 1.73 m2) undergoing elective CT scanning with intravenous contrast agent. Although patients were considered to be at risk for postcontrast acute kidney injury (PC-AKI), average serum creatinine concentration increased by 2% after 5-7 days with no serious persistent decline in renal function. No significant differences were found between treatment and no treatment arms of the study. Results are in agreement with previous trials and confirm that risk of clinically relevant PC-AKI is very low and that prehydration is not warranted in this group of patients. Patients with an eGFR of less than 30 ml/min per 1.73 m2 and multiple AKI risk factors have a higher risk of PCI-AKI and may benefit from prehydration, although the risk-benefit balance remains unclear.