There is clinical evidence that patients with elevated cholesterol levels who begin taking statins within three to six months after acute myocardial infarction (AMI) have reduced mortality rates. Stenestrand and Wallentin, for the Swedish Register of Cardiac Intensive Care (RIKS-HIA), conducted this prospective cohort study to determine if statin use initiated at the time of the AMI was associated with lower one-year mortality rates.
The Swedish Register of Cardiac Intensive Care records information such as medical history, demographics, electrocardiographic changes and interventions at admission, at discharge and during the hospital stay. Patients who had a diagnosis of first recorded AMI were included in the study. The National Cause of Death Register was used to determine one-year mortality data for patients determined to have a diagnosis of AMI. Patients who died before discharge were excluded from the study. Patients older than 80 years were also excluded from the study (because of the low rate of statin use in this group).
There were 19,599 patients younger than 80 years who were diagnosed with AMI between 1995 and 1998. Of these, 5,528 received statins at discharge from the hospital. Patients receiving statins were younger, less likely to have diabetes mellitus or heart failure, and more likely to have previous myocardial infarction, to be smokers or to have a history of coronary artery interventions (e.g., angioplasty or bypass graft surgery). Factors most strongly associated with patients receiving statins at discharge were previously received statins, later admission year, younger age, beta blocker therapy at discharge, and absence of atrial fibrillation. The unadjusted one-year mortality in patients not receiving statins was 9.3 percent, compared with 4.0 percent in patients who did receive statins (relative risk: 0.75). Subgroup analysis also supported the benefit associated with early statin use in patients with AMI. The greatest reduction in one-year mortality occurred in patients between 60 and 69 years of age. One-year mortality was reduced regardless of gender, presence of diabetes mellitus or heart failure, or treatment with diuretics, digitalis, beta blockers or anticoagulants.
The Register group concludes that initiation of statin treatment before or at the time of hospital discharge in a patient who has had AMI and has total cholesterol or low-density lipoprotein cholesterol levels above the current guidelines is beneficial and safe, and is associated with a reduction in one-year mortality.