Conflicting MI Trends in Young and Old: FAST-MI

August 27, 2012

August 27, 2012 (Munich, Germany) — While the overall mortality rate after ST-elevation MI (STEMI) has decreased over the past 15 years, the reasons for this are not just due to better treatment strategies. Rather, new French data show a worrying trend of more MIs occurring in younger people, particularly women [1].

Dr Nicholas Danchin (Hôpital Européen Georges Pompidou, Paris, France), senior investigator of the French Registry of Acute ST-Elevation and Non–ST-Elevation Myocardial Infarction (FAST-MI) study, told heartwire : "There seems to be two different trends occurring--the MI mortality risk in older patients, whom we traditionally think of as MI candidates, is falling, probably because of better primary-prevention efforts in people with recognized risk factors, together with faster treatment and more use of primary PCI when the MI occurs. But there is a worrying increase in MI in younger people--particularly younger women (under 60 years) who smoke."

Younger Women: New Target Group for Prevention

Danchin said he was surprised to see the large increase in MIs in younger women. "This is a group that has always been thought to have a very low risk, but we saw a large increase in MI in those in this group that did not have any recognized risk factors apart from smoking. We have known for a while that smoking rates in younger women are increasing. Now we have shown that this is having the direct consequence of an increase in MI. So this is a new target group to whom we need to direct the prevention message."

The results of the FAST-MI study were presented here today at the European Society of Cardiology 2012 Congress and simultaneously published in the Journal of the American Medical Association. Researchers analyzed data from four one-month French nationwide registries, conducted five years apart (1995 to 2010), which included a total of 6707 STEMI patients.

During the study period, 30-day mortality decreased from 13.7% to 4.4% in STEMI patients; mortality decreased from 9.8% to 2.6% in men and from 23.7% to 9.8% in women.

The average age of those with STEMI declined from 66.2 years to 63.3 years over the study period. This appeared to be due to an increase in the proportion of younger women (<60 years) with STEMI. "The proportion of younger patients developing STEMI despite not having hypertension, diabetes, or hypercholesterolemia increased markedly, particularly in younger women," Danchin said.

He noted that younger women still represent a small proportion of all MI patients (about 7% to 8%), but this up from about 2% to 3% 15 years ago. "Among women who develop an MI, 25% are now in the under-60 age group, up from 12% in 1995. And the number [of MIs] in women under age 50 is increasing even more quickly, up from around 3% in 1995 to 11% in 2010. The most likely explanation for this is the increased prevalence of smoking in younger women," he commented.

Smoking Worse Than Obesity

Danchin noted that smoking rates in younger women who have had an MI dramatically increased over 1995 to 2010, from 37% to 73%. While obesity rates also increased in this group--up from 18% in 1995 to 27% in 2010--Danchin believes this is doing less damage than smoking. "Smoking is definitely worse than obesity for MI risk. It is better to put on some weight and give up smoking, but fear of weight gain is one reason why many women don't stop smoking." He added that among this MI population, women smokers had an average body-mass index two points lower than nonsmokers, so "smokers are definitely leaner."

Other study findings include increased use of reperfusion therapy, from 49% to 75%, and more frequent use of primary PCI, from 12% to 61%, between 1995 and 2010. There was also increased use of beta blockers, ACE inhibitors, or angiotensin-receptor blockers (ARBs), statins, antiplatelet agents, and low-molecular-weight heparins. In addition, time from symptom onset to hospital admission decreased, with a shorter time from onset to first call, and broader use of mobile intensive-care units.