In this prospective study including 949 patients from 160 centres across the UK and Republic of Ireland, researchers investigated the impact of peri-operative withholding of angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers on the risk of acute kidney injury following major non-cardiac surgery. Eligible patients were those undergoing elective major surgery on the gastrointestinal tract and/or the liver. These subjects were examined for the development of acute kidney injury within seven days of operation, using adjusted multi-level models and propensity score matching. They found no benefit of withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers on the prevention of the development of postoperative acute kidney injury, as observed after propensity matching.