Impact of Statin Use on Outcomes After Coronary Artery Bypass Graft Surgery

Abstract

Background— The benefits of statins have been demonstrated for patients with a remote history of coronary artery bypass grafting (CABG); however, no investigation to date has evaluated whether initiation of statin therapy in the early months after surgery improves clinical outcomes. Methods and Results— A retrospective cohort of 7503 Medicare patients ≥65 years of age who underwent CABG (1995–2003) was assembled by use of linked hospital and pharmacy claims data. Rates of all-cause mortality and major adverse cardiovascular events were compared between patients who were (n=1745) and were not (n=5788) prescribed statins within 1 month of CABG discharge. Additional analyses evaluated the impact of statin initiation between 1 and 6 months after surgery. Multivariable and propensity score analysis demonstrated that statin use within 1 month of CABG discharge independently reduced the risk of all-cause mortality (adjusted hazard ratio 0.82, 95% confidence interval 0.72 to 0.94) compared with no statin use. Similarly, statin use within 1 month of CABG discharge independently reduced the risk of major adverse cardiovascular events (adjusted hazard ratio 0.89, 95% confidence interval 0.81 to 0.98). Initiation of statin therapy between 1 and 6 months after CABG discharge was also associated with reductions in major adverse cardiovascular events and mortality; however, outcome rates between early (≤1 month after CABG) and delayed (1 to 6 months after CABG) statin initiation were not significantly different. Conclusions— Statin therapy initiated in the early months after hospital discharge independently reduces all-cause mortality and major adverse cardiovascular events after CABG. These findings validate the widespread practice of prescribing long-term statin therapy after CABG.