The association of withholding or continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers on acute kidney injury after non-cardiac surgery

Background: Withholding or continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers peri-operatively in non-cardiac surgery remains controversial as they may result in intra-operative hypotension and postoperative organ damage. Methods: We included patients prescribed angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers who underwent surgical procedures > 1 h duration under general or spinal anaesthesia from January 2012 to June 2022 in a single centre. We categorised patients by whether these drugs were withheld for 24 h before surgery. We evaluated the association of withholding these drugs before non-cardiac surgery with creatinine concentrations that increased ≥ 26.4 μmol.l^-1 in the first 48 postoperative hours (acute kidney injury). We also analysed changes in creatinine concentrations and estimated glomerular filtration rates. Results: Angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers were withheld in 24,285 of 32,933 (74%) patients and continued in 8648 (26%) patients. We used propensity scores for drug discontinuation to match 8631 patient pairs who did or did not continue these drugs: acute kidney injury was recorded for 1791 (21%) patients who continued these drugs vs. 1587 (18%) who did not (OR (95%CI) 1.16 (1.08–1.25), p < 0.001). Intra-operative hypotension was recorded for 3892 (45%) patients who continued drugs vs. 3373 (39%) patients who did not (OR (95%CI) 1.28 (1.21–1.36), p < 0.001). Continuing drugs was independently associated with a mean increase in creatinine of 2.2 μmol.l^-1 (p < 0.001) and a mean decrease in estimated glomerular filtration rate of 1.4 ml.min.1.73 m^-2 (p < 0.001). Conclusions: Continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers 24 h before non-cardiac surgery was associated with intra-operative hypotension and postoperative acute kidney injury.