Impact of combination medical therapy on mortality in vascular surgery patients

Abstract

Th use of beta-blockers or statins has been associated with decreased mortality after noncardiac surgery. There are no prior perioperative studies of concurrent use of other cardioprotective drugs. To ascertain whether combinations of aspirin, beta-blockers, statins, and/or angiotensin-converting enzyme (ACE) inhibitors were associated with decreased mortality 6 months after vascular surgery. We performed a retrospective cohort study on the 3020 patients who underwent vascular surgery between January 1998 and March 2005 at 5 regional Veterans Affairs (VA) medical centers. The Cochran-Mantel-Haenszel test was used to assess associations with 6-month all-cause mortality for the combination drug exposures compared to no exposure while adjusting for propensity score. Exposure to all 4 of the study drugs compared to none had a propensity-adjusted relative risk (aRR) of 0.52 (95% confidence interval [CI], 0.26-1.01; P = 0.052), number needed to treat (NNT) 19; 3 drugs vs. none, aRR 0.60 (95% CI, 0.38-0.95; P = 0.030), NNT 38; 2 drugs vs. none, aRR 0.68 (95% CI, 0.46-0.99; P = 0.043), NNT 170; and 1 drug vs. none, aRR 0.88 (95% CI, 0.63-1.22; P = 0.445). ACE inhibitor exposure was common in all combinations. Combination use of 2 to 3 study drugs, some of which included ACE inhibitors, was associated with decreased mortality after vascular surgery. Combination use of all 4 study drugs was not statistically significant due to the small number of events in this group. Further prospective studies of combination perioperative aspirin, beta-blockers, statins, and ACE inhibitors are warranted.