Prevention Efforts Seem to Be Paying Off as Acute MIs Continue Slide

Continuing the trend from an earlier time period, overall acute MI rates remained on a downward slope from 2008 to 2014 in a large, integrated healthcare system caring for nearly 4 million people, with benefits seen across patient subgroups, a new study shows.

There’s uncertainty about the largest drivers of the trend, but the persistent improvement is likely related mostly to aggressive use of primary prevention approaches, including system-wide programs to control blood pressure, lipids, and diabetes and to ensure optimal use of preventive medications as well as efforts to encourage healthy smoke-free lifestyles with high levels of physical activity and healthy diets, lead author Matthew Solomon, MD, PhD (Kaiser Permanente Northern California, Oakland), told TCTMD.

“I think it’s safe to say that all of those efforts are likely what’s contributing to these pretty dramatic declines in myocardial infarction,” he said. “We should be very encouraged by these results.”

The findings, published in a research letter in the August 9, 2016, issue of the Journal of the American College of Cardiology, extend the results of a prior analysis showing marked reductions in acute MI rates from 1999 to 2008 in the Kaiser Permanente North California (KPNC) system.

For the new study, the investigators looked at administrative claims data on 29,087 adult patients hospitalized for acute MI out of 3,966,248 patients enrolled for at least 1 year within KPNC between 2008 and 2014.

Over that time, rates (per 100,000 person-years) of acute MI declined:

• Overall: from 225 to 173
• NSTEMI: from 177 to 136
• STEMI: from 47 to 37

Rates were higher in men than in women, although declines were seen in both sexes. MI was more frequent among older patients, but percentage declines were roughly similar across groups, ranging from 27.0% to 33.1%.

Diabetics were about six to seven times more likely to be hospitalized for acute MI than were nondiabetics, but both groups saw reductions (21% in diabetics and 26% in nondiabetics).

Solomon noted that in the earlier time period, the decline in overall acute MI was driven by substantial reductions in STEMIs, whereas in more recent years, NSTEMIs accounted for the bulk of the drop. From 2008 to 2014, there were similar percentage declines in STEMI and NSTEMI, but the rate of decline for STEMI slowed compared with the earlier study.

“It’s possible that given aggressive primary and secondary prevention . . . STEMIs could just be reaching a natural plateau and that the drivers of residual STEMIs may not be the traditionally targeted and modifiable risk factors,” Solomon said.

He and his colleagues acknowledge that the findings may not be fully generalizable to other settings, areas of the country, or uninsured patients, but Solomon pointed out that a Medicare analysis published earlier this year also showed declines in acute MI rates over time through 2013.

“Good things are happening nationally, as well, which is, I think, heartening for all cardiologists,” Solomon said.

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