The evidence has made it clear that aspirin, [beta]-blockers, lipid-lowering agents, and angiotensin-converting enzyme (ACE) inhibitors act to prevent future ischemic events in patients with coronary artery disease. In order for such drugs to be effective, however, two things must happen: they must be prescribed, and patients have to take them.

In order to ascertain long-term outpatient use of these medications, researchers analyzed the Duke Databank for Cardiovascular Disease, a clinical database comprising the 31,750 patients who've undergone a cardiac procedure at Duke Medical Center in Durham, North Carolina, since 1969. Since 1995, annual follow-up surveys have been conducted in this population; for the study reported here, data from the 1995 through 2002 surveys were analyzed.

The good news is that the use of all four types of medication increased each year, indicating, perhaps, that prescribing practices and education are improving. By 2002, 83% of patients were taking aspirin, and more than half were taking a [beta]-blocker (61%), a lipid-lowering agent (63%), or aspirin plus a [beta]-blocker (54%). In a subgroup of patients who had coronary artery disease (CAD) but not heart failure, 39% were using ACE inhibitors, and in those with CAD and heart failure, the rate of ACE use in 2002 was 51% (up from 32% in 1995).

The bad news is that consistent use of any agent (defined as "reporting a medication use on at least two consecutive occasions and continuing to do so until death, withdrawal from follow-up, or the end of the study period") except aspirin was rare; rates of consistent use remained below 50%, and only a fifth of patients were consistently taking aspirin, a [beta]-blocker, and a lipid-lowering agent. And inconsistent use did not confer the same preventive benefit that consistent use did. Patients who always used an evidence-based agent had better chances of survival than those who did not.

Analysis of patient characteristics showed that those who were at greatest risk for subsequent ischemic coronary events and death were the least likely to be taking the necessary medications: "the elderly and patients with diabetes and evidence of heart failure." The study authors write that, "It may be possible to design educational and compliance intervention programs targeted to groups of patients at high risk for both underuse of medications in secondary prevention and adverse clinical outcomes."

Newby LK, et al. Circulation 2006;113(2): 203-12.