Association between preoperative diuretic use and in-hospital outcomes after cardiac surgery

Background: There is a paucity of evidence on the association between preoperative diuretics use and outcomes following cardiac surgery. We hypothesized that diuretic use prior to cardiac surgery will be associated with adverse in-hospital clinical outcomes. Methods: We evaluated patients undergoing cardiac surgery at a single institution between January 1, 2000, and December 31, 2011. Patients were grouped as follows: isolated coronary artery bypass grafting (CABG) (n = 8759), CABG plus valve surgery (n = 1188), and valve surgery only (n = 2646). A fourth group "All cardiac surgery" is comprised of patients from all three groups. Preoperative diuretic use was defined as patient on any diuretic till the day of surgery. Primary outcome was the incidence of major adverse events (MAEs) defined as the composite of mortality, postoperative renal dysfunction, myocardial infarction, stroke, and new-onset atrial fibrillation (AF). Logistic regression analysis and propensity score matching were performed. Results: We included 12,593 patients [3546 on diuretic (28%)]. After logistic regression analyses, preoperative diuretic use was associated with an increased risk of the following: (1) MAE among all groups except the concomitant CABG and valve surgery group, (2) AF in "All cardiac surgery" and isolated CABG groups, (3) postoperative renal dysfunction in all groups. After propensity score matching (n = 3050 in each group), preoperative diuretic use was significantly associated with MAE (48% vs. 43%; P < 0.0001), postoperative renal dysfunction (19% vs. 14%; P < 0.0001), and AF (34% vs. 32%; P = 0.03) in the "All cardiac surgery" group. Conclusion: Preoperative diuretics use is associated with an increased incidence of MAEs after cardiac surgery.