LAUSR

Background: Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers improve cognitive function. The authors therefore tested the primary hypothesis that preoperative use of angiotensin inhibitors is associated with less delirium in critical care patients. Post hoc, the association between postoperative use of angiotensin system inhibitors and delirium was assessed. Methods: The authors conducted a single-site cohort study of adults admitted to Cleveland Clinic critical care units after noncardiac procedures between 2013 and 2018 who had at least one Confusion Assessment Method delirium assessment. Patients with preexisting dementia, Alzheimer’s disease or other cognitive decline, and patients who had neurosurgical procedures were excluded. For the primary analysis, the confounder-adjusted association between preoperative angiotensin inhibitor use and the incidence of postoperative delirium was assessed. Post hoc, the confounder-adjusted association between postoperative angiotensin system inhibitor use and the incidence of delirium was assessed. Results: The incidence of delirium was 39% (551 of 1,396) among patients who were treated preoperatively with angiotensin system inhibitors and 39% (1,344 of 3,468) in patients who were not. The adjusted odds ratio of experiencing delirium during critical care was 0.98 (95% CI, 0.86 to 1.10; P = 0.700) for preoperative use of angiotensin system inhibitors versus control. Delirium was observed in 23% (100 of 440) of patients who used angiotensin system inhibitors postoperatively before intensive care discharge, and in 41% (1,795 of 4,424) of patients who did not (unadjusted P < 0.001). The confounder-adjusted odds ratio for experiencing delirium in patients who used angiotensin system inhibitors postoperatively was 0.55 (95% CI, 0.43 to 0.72; P < 0.001). Conclusions: Preoperative use of angiotensin system inhibitors is not associated with reduced postoperative delirium. In contrast, treatment during intensive care was associated with lower odds of delirium. Randomized trials of postoperative angiotensin-converting enzymes inhibitors and angiotensin receptor blockers seem justified. In a single-center cohort study of adults admitted to a surgical intensive care unit, preoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers was not associated with reduced postoperative delirium. However, rapidly starting angiotensin-converting enzyme inhibitors or angiotensin receptor blockers postoperatively was associated with reduced delirium.