ST elevation myocardial infarction epidemiology and demographics

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Associate Editors-In-Chief: Yuri B. Pride, M.D. [mailto:ypride@bidmc.harvard.edu] ;

Overview
Myocardial infarction is a common presentation of ischemic heart disease. The World Heart Organization (WHO) estimated in 2002 that, 12.6 percent of deaths worldwide were from ischemic heart disease.

Ischemic heart disease is the leading cause of death in developed countries, but third to AIDS and lower respiratory infections in developing countries.

Over 9 million patients in the United States alone have angina. An estimated 80,700,000 American adults (one in three) have one or more types of cardiovascular disease (CVD), of whom 38,200,000 are estimated to be age 60 or older. Except as noted, the estimates were extrapolated to the U.S. population in 2005 from NHANES 1999–2004. (Total CVD includes diseases in the bullet points below except for congenital heart disease). Due to overlap, it is not possible to add these conditions to arrive at a total.


 * Hypertension: 73,000,000
 * Coronary heart disease: 16,000,000
 * Myocardial infarction: 8,100,000
 * Angina pectoris: 9,100,000


 * Heart failure: 5,300,000
 * Stroke: 5,800,000
 * Congenital heart disease: 650,000 – 1,300,000

This means that roughly every 65 seconds, an American dies of a coronary event.

The following prevalence estimates are for people age 18 and older from NCHS/NHIS, 2005:

 * Among whites only, 12.0% have heart disease, 6.6% have CHD, 21.0% have hypertension and 2.3% have had a stroke.
 * Among blacks, 10.2% have heart disease, 6.2% have CHD, 31.2% have hypertension and 3.4% have had a stroke.
 * Among Hispanics or Latinos, 8.3% have heart disease, 5.9% have CHD, 20.3% have hypertension and 2.2% have had a stroke.
 * Among Asians, 6.7% have heart disease, 3.8% have CHD, 19.4% have hypertension and 2.0% have had a stroke.
 * Among Native Hawaiians or other Pacific Islanders, 22.4% have hypertension (other prevalence estimates considered unreliable).

Although it is difficult to ascertain the true incidence of ST elevation myocardial infarction (STEMI), according to the ACC/AHA guidelines, a conservative estimate is that approximately 500,000 patients suffer STEMI each year. The incidence of STEMI has decreased over time. In an observational study of 5,832 metropolitan patients spanning from 1975 to 1997, the incidence of STEMI decreased from 171/100,000 to 101/100,000

Risk factors for STEMI mirror those for coronary artery disease (CAD) and include diabetes mellitus, cerebrovascular disease manifested by stroke or transient ischemic attack, peripheral arterial disease, aortic atherosclerosis and aneurysm, age (male ≥45 years old, female ≥55 years old), family history of premature CAD (MI or sudden death before age 55 in a first-degree male relative or before age 65 in a first-degree female relative), tobacco abuse, hypertension, hyperlipidemia and low high-density lipoprotein (HDL)

The mortality among patients who suffer STEMI has progressively declined in recent years. From 1975 to 1997, one observational study reported that the in-hospital mortality decreased from 24% to 14%. In the Global Registry of Acute Coronary Events (GRACE), a multinational cohort study that includes 16,814 patients with STEMI were enrolled and followed up in 113 hospitals in 14 countries between 1999 and 2006, in-hospital mortality declined from 8.4% in 1999 to 4.6% in 2005.

The reason for this decline in mortality is likely multifactorial and includes, but is certainly not limited to, decline in symptom onset-to-presentation time, more widespread use of primary PCI, improvements in time to reperfusion (door-to-needle and door-to-balloon times) and improved medical therapy, including increases in the use of evidence-based therapies such as aspirin  , beta blockers  , clopidogrel  , statins and angiotension converting enzyme inhibitors or angiotensin receptor blockers.