David Brill
A decrease in the severity of heart attacks is fuelling the decline in coronary heart disease (CHD) deaths in the US, new research suggests.
The study – an analysis of 10,285 myocardial infarction (MI) cases hospitalized over 15 years – showed significant declines across almost all indicators of severity.
This trend, which appears to be mirrored by data from some parts of Asia, was independent of either gender or ethnicity.
“This landmark study suggests that better prevention and better management in the hospital have contributed to the reduction in deaths,” said Dr. Merle Myerson, principal investigator of the Atherosclerosis Risk in Communities (ARIC) study, published in Circulation. [2009 Jan 19; Epub ahead of print]
“Better control of risk factors for heart disease, such as blood pressure and cholesterol, as well as improvements in hospital management, may lessen the severity if somebody has a heart attack,” he said.
The time between symptom onset and arrival at hospital remained constant throughout the study, period with only around a third of patients arriving at the hospital within 2 hours of an attack.
Dr. Adrian Low, a consultant at the National University Heart Centre Singapore, stressed the importance of raising public awareness in order to further improve MI outcomes.
“While this study is reassuring, it also emphasizes that we still have room for improvement. A significant percentage of patients still present late to us for treatment,” he said.
“We know that early presentation and appropriate management can result in better outcomes. This will only be achieved with enhanced public education and a better evaluation of how we can overcome our shortcomings,” he added.
The ARIC investigators reviewed MI discharge data from 1987 to 2002, taken from hospitals across four communities in North Carolina, Maryland, Mississippi and Minnesota. The analysis was limited to white and African-American patients, aged 35 to 74.
Previous studies had shown that CHD mortality in the US was dropping but that the incidence of MI remained unchanged – prompting the researchers to investigate whether declining MI severity might be the driving force behind the bigger-picture CHD effect.
In-hospital deaths from acute MI in Singapore have also dropped over a similar period, according to data from the National Heart Center, where overall inpatient mortality declined from 20.6 percent in 1988 to 14.7 percent in 2002. [Ann Acad Med Singapore 2007 Dec;36(12):974-9] A study published last year by the Singapore’s National University Hospital, meanwhile, showed that the use of evidence-based medications for MI has significantly reduced 1-year mortality in both elderly and young patients. [Am J Geriatr Cardiol 2008 Jan-Feb;17(1):21-6]
Low added that the ARIC study “reinforces our current understanding that cardiovascular risk factors, treated aggressively, can impact on subsequent development and outcome of acute MI,” but noted that there are several limitations to the research. The generalizability to other populations is not clear, nor is it known which specific measures led to the improved outcomes, he said. He also added that some of the severity indicators used by the researchers are proxies for disease severity, while more direct measures such as left ventricular ejection fraction were unavailable.
Twenty MI severity indicators were used in the ARIC study, including the proportion of cases having major ECG abnormalities. For ST-segment elevation, for example, the proportion of cases dropped by 1.9 percent per year (P = 0.002), while the percentage of cases with any major Q wave dropped by 4.5 percent per year (P<0.001).>
The study – an analysis of 10,285 myocardial infarction (MI) cases hospitalized over 15 years – showed significant declines across almost all indicators of severity.
This trend, which appears to be mirrored by data from some parts of Asia, was independent of either gender or ethnicity.
“This landmark study suggests that better prevention and better management in the hospital have contributed to the reduction in deaths,” said Dr. Merle Myerson, principal investigator of the Atherosclerosis Risk in Communities (ARIC) study, published in Circulation. [2009 Jan 19; Epub ahead of print]
“Better control of risk factors for heart disease, such as blood pressure and cholesterol, as well as improvements in hospital management, may lessen the severity if somebody has a heart attack,” he said.
The time between symptom onset and arrival at hospital remained constant throughout the study, period with only around a third of patients arriving at the hospital within 2 hours of an attack.
Dr. Adrian Low, a consultant at the National University Heart Centre Singapore, stressed the importance of raising public awareness in order to further improve MI outcomes.
“While this study is reassuring, it also emphasizes that we still have room for improvement. A significant percentage of patients still present late to us for treatment,” he said.
“We know that early presentation and appropriate management can result in better outcomes. This will only be achieved with enhanced public education and a better evaluation of how we can overcome our shortcomings,” he added.
The ARIC investigators reviewed MI discharge data from 1987 to 2002, taken from hospitals across four communities in North Carolina, Maryland, Mississippi and Minnesota. The analysis was limited to white and African-American patients, aged 35 to 74.
Previous studies had shown that CHD mortality in the US was dropping but that the incidence of MI remained unchanged – prompting the researchers to investigate whether declining MI severity might be the driving force behind the bigger-picture CHD effect.
In-hospital deaths from acute MI in Singapore have also dropped over a similar period, according to data from the National Heart Center, where overall inpatient mortality declined from 20.6 percent in 1988 to 14.7 percent in 2002. [Ann Acad Med Singapore 2007 Dec;36(12):974-9] A study published last year by the Singapore’s National University Hospital, meanwhile, showed that the use of evidence-based medications for MI has significantly reduced 1-year mortality in both elderly and young patients. [Am J Geriatr Cardiol 2008 Jan-Feb;17(1):21-6]
Low added that the ARIC study “reinforces our current understanding that cardiovascular risk factors, treated aggressively, can impact on subsequent development and outcome of acute MI,” but noted that there are several limitations to the research. The generalizability to other populations is not clear, nor is it known which specific measures led to the improved outcomes, he said. He also added that some of the severity indicators used by the researchers are proxies for disease severity, while more direct measures such as left ventricular ejection fraction were unavailable.
Twenty MI severity indicators were used in the ARIC study, including the proportion of cases having major ECG abnormalities. For ST-segment elevation, for example, the proportion of cases dropped by 1.9 percent per year (P = 0.002), while the percentage of cases with any major Q wave dropped by 4.5 percent per year (P<0.001).>