There are limited data on the recent trend in the use of optimal evidence-based medical therapies after acute coronary syndromes (ACSs). We sought to evaluate (1) the temporal changes in medical management of patients discharged after an ACS; (2) patient and practice characteristics associated with optimal medical therapy at discharge; and (3) the association between discharge medication use and 1-year outcome.

The Canadian ACS I (September 1999-June 2001) and ACS II (October 2002-December 2003) Registries were prospective, multicenter, observational studies of 6853 patients admitted for ACS. We examined the discharge use of medications among 5833 hospital survivors who did not have any contraindications to antiplatelet/anticoagulant, β-blocker, angiotensin-converting enzyme inhibitor, or lipid-modifying therapies. Optimal medical therapy was defined as the use of all indicated medications. Follow-up data at 1 year were collected by telephone interview. We performed hierarchical logistic regression to identify patient characteristics and care patterns associated with optimal medical treatment and to examine its relationship with 1-year mortality.

There were significant increases in the discharge use of all 4 classes of medications over time; 28.9% and 51.8% of patients in ACS I and ACS II Registries, respectively, were prescribed optimal medical therapy (P < .001). Advanced age, female sex, prior heart failure, renal dysfunction, and coronary bypass surgery during hospitalization were negative independent predictors of optimal medical therapy. Conversely, enrollment in ACS II Registry, history of dyslipidemia, presence of ST elevation and abnormal cardiac biomarker, previous myocardial infarction, and previous coronary revascularization were independently associated with the use of combination therapy. After adjusting for other validated prognosticators, patients receiving optimal medical therapy had significantly lower 1-year mortality (adjusted odds ratio 0.54, 95% confidence interval 0.36-0.81, P = .003) compared with those given 0 or 1 drug at discharge. Over the 1-year follow-up period, substantial numbers of patients discontinued therapies, whereas others were initiated on treatment.

Despite the temporal increases in the combined use of evidence-based pharmacologic therapies, which is associated with improved outcome, medical management of ACS remains suboptimal. Quality improvement strategies are needed to enhance the appropriate use of effective therapies, targeting specifically the high-risk but undertreated patients who may derive the greatest therapeutic benefit.