Fatal and nonfatal MI rates fell in past decade
MedWire News: Researchers have documented reductions in fatal and nonfatal myocardial infarction (MI) since 1999 in a large, community-based population in the USA.
The team says these reductions correlate with increased use of cardioprotective medications, drugs that may not only influence risk factors but also lower the severity of subsequent cardiac events.
Alan Go (Kaiser Permanente Northern California, Oakland, USA) and colleagues identified a total of 46,086 hospitalizations for MI between 1999 and 2008 in a large, integrated healthcare delivery system.
They report in the New England Journal of Medicine that the age- and gender-adjusted incidence of MI increased from 274 cases per 100,000 years in 1999 to a peak of 287 cases per 100,000 years in 2000, before falling yearly thereafter down to 208 cases per 100,000 person-years in 2008. Analysis showed this equated to a 24% relative decrease between 1999 and 2008.
The age- and gender-adjusted incidence of ST-segment elevation MI (STEMI) fell from 133 cases per 100,000 persons in 1999 to 50 cases per 100,000 persons in 2008 (a 62% relative decrease), whereas that for non-ST-segment elevation MI (NSTEMI) increased from 155 cases per 1000,000 persons in 1999 to 202 per 100,000 persons in 2004 before decreasing thereafter.
The authors note that expanded use of troponin testing in more recent years makes the overall reductions in MI “even more striking.”
The rate of revascularization within 30 days after MI went up from 40.7% in 1999 to 47.2% in 2008; for STEMI the rate increased from 49.9% to 69.6% and for NSTEMI from 33.4% to 41.3%.
Age- and gender-adjusted 30-day mortality after MI declined overall from 10.5% in 1999 to 7.8% in 2008, which was driven by a reduction in case fatality rate from 10.0% to 7.6% for NSTEMI, with no significant change in that for STEMI.
After multivariable adjustment the odds for death at 30 days post MI was a significant 24% lower in 2008 than in 1999. Similarly, the risk for 30-day death after NSTEMI reduced significantly over time, at a corresponding 18% reduced odds.
In contrast, adjusted mortality did not change among STEMI patients, with a nonsignificant 7% lower odds for 30-day death in 2008 compared with 1999.
The authors observe that the reduction in MI, particularly STEMI, incidence likely reflects substantial improvements in primary prevention approaches.
Furthermore, they add, the trends occurred despite the increased sensitivity of new biomarkers for the diagnosis of MI and the increasing prevalence of selected cardiovascular risk factors (obesity and diabetes).
In an accompanying editorial, Jeremiah Brown and Gerald O’Connor (both of Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, New Hampshire, USA) note that despite the improvements, preventive opportunities are still being missed.
In particular they highlight the importance of environment, lifestyle, and nutritional approaches.
“We must not only encourage our society to work toward better health through physical activity, improved nutrition, and abstinence from smoking, but also create active communities that can support healthier lifestyles,” they write.
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By Caroline Price