© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell. BACKGROUND: Patients with coronary heart disease are recommended to use statins following hospital discharge. Acute myocardial infarction (AMI) is a common complication of hospitalization, but the use of statins following discharge among patients who were not initially hospitalized for AMI has not been assessed adequately.METHODS AND RESULTS: Using the Medicare 5% national random sample, we determined statin use among beneficiaries who were hospitalized and who had a secondary discharge diagnosis of AMI and among beneficiaries who had a primary discharge diagnosis of AMI, coronary artery bypass grafting, or percutaneous coronary intervention in 2007-2009. Statin use was defined by a pharmacy (Medicare Part D) claim within 90 days following discharge. Of 8175 Medicare beneficiaries who did not take statins prior to hospitalization, 31.2% with AMI as a secondary discharge diagnosis, 60.5% with AMI as the primary discharge diagnosis, 67.6% with coronary artery bypass grafting, and 63.9% with a percutaneous coronary intervention initiated statins. After multivariable adjustment, the risk ratio for statin initiation comparing beneficiaries with a secondary versus primary discharge diagnosis of AMI was 0.59 (95% CI 0.54 to 0.65). Among 5468 Medicare beneficiaries taking statins prior to hospitalization, statin use following discharge was lower for those with AMI as a secondary discharge diagnosis (71.8%) compared with their counterparts with AMI, coronary artery bypass grafting, and percutaneous coronary intervention (84.1%, 83.8%, and 87.3%, respectively) as the primary discharge diagnosis.CONCLUSION: Medicare beneficiaries with a secondary hospital discharge diagnosis of AMI were less likely to fill statins compared with those with other coronary heart disease events.