Early and pre-discharge aspirin administration among patients with acute myocardial infarction: Current clinical practice and trends in the United States

Objectives: The purpose of our study was to determine the frequency of aspi rin administration among patients with acute myocardial infarction (MI) as dictated by physicians practicing in the United States. Background: Aspirin (ASA), a widely available, inexpensive and generally we ll-tolerated platelet inhibitor, is recommended for patients with acute cor onary syndromes, including acute MI. However, there is concern that aspirin is underutilized in daily clinical practice. Methods: Early (< 24 hours) and predischarge ASA administration were determ ined among 220,171 patients with suspected acute MI enrolled in the Second National Registry of Myocardial Infarction (NRMI 2) between June, 1994 and April 30, 1996. Results: Overall, 165,122 (74.9%) of patients received ASA within 24 hours of hospital admission, whereas 55,049 patients did not. Early ASA recipient s were younger, more often male, arrived at the hospital earlier, and were more likely to be classified as Killip Class II or less compared to those w ho did not receive ASA. Patients who received aspirin were also more likely to have chest pain, electrocardiographic ST segment elevation, and tended to arrive at the hospital earlier than those who did not receive ASA. Howev er, over 20% of patients with ST segment elevation did not receive early AS A therapy. From the total cohort of early ASA recipients, only 69% received ASA at the time of hospital discharge. Trends in early and pre-discharge aspirin admi nistration over a 2 year time period in all patients (72.6 to 75.1% and 71. 5 to 74.6%, respectively; p < 0.001) and in specific patient subsets were e ncouraging with a gradual but steady increase; however, utilization remaine d comparatively low in women and the elderly. By multivariable analysis, in -hospital recurrent MI (OR 0.90, 95% CI; .78-1.0, p = 0.04), stroke (OR 0.6 5, 95% CI, .52-.80, p < 0.001) and death (OR 0.24, 95% CI, .22-.26, p < 0.0 01) occurred less frequently when ASA was administered within 24 hours of h ospitalization. Conclusion: Aspirin is currently underutilized in routine clinical practice as both primary and adjunctive forms of therapy in MI, especially among pa tients known to be at risk for recurrent cardiothrombotic events. The targe ted and timely use of aspirin reduces early cardiovascular events and shoul d remain a priority in national health care efforts.