Bad livin' is protective, sort of ... mortality from 1st MI inversely related to risk factors
According to compelling new data, you can win the genetic lottery and live healthy all your life, and you'll still be more likely to die from your first heart attack than the diabetic guy in the next bed who keeps going outside to smoke to relieve his chest pain. But you'll at least have had more time to get your affairs in order, it seems.
Canto et al peered into the National Registry of Myocardial Infarction, 1994-2006, and analyzed 542,008 cases of people hospitalized with their first myocardial infarction without a prior history of cardiovascular disease. What can we learn from this awesome data set?
One in 7 (14%) of people experiencing their first MI had none of the 5 major risk factors for coronary artery disease (hypertension, smoking, dyslipidemia, diabetes, family history of CAD). Yikes!
(Granted, there are many other less robust risk factors for MI, like obesity, which may have been present and were not captured by this database.)
These low-risk people tended to put off their first MI to an average age of 71.5 -- as opposed to those with 5 risk factors, whose average age was a ripe old 57 at the time of their first MI.
The more risk factors you had, the less likely you were to die in the hospital after your first MI:
0 risk factors : 15% in-hospital mortality
1 risk factor: 11%
2 risk factors: 8%
People with 3 (5%), 4 (4%), and 5 risk factors (3.6%) had the lowest mortality.
Authors fretted about self-reporting bias possibly influencing this relationship (think of an intubated or confused older patient -- sicker and more likely to die, and also likely to under-report risk factors). They performed "extreme sensitivity analyses," which sounds like something they do at Guantanamo. In effect, they re-ran the analyses after segmenting the population into age-groups, and after excluding various segments (particularly the people with zero risk factors). The relationship, & its stat.significance, persisted.
Of course, these are just the people who made it to the hospital. Is there a morbid, but silver-haired lining here? If heart attacks in healthy people are more severe and mortal, but occur later in life, could an even larger number of folks have died suddenly at home, well into their 70s or 80s, a snifter of brandy in one hand, the other petting Rufus, their old trusty Labrador when the widowmaker strikes? Invisible in registries and clinical trials, their passing noted only in kindly worded euologies and obituaries in folksy local newspapers? These are the thoughts that comfort me. I'm sure you're amazing doctors, but I don't want to get to know you all (as your patient) if I don't have to.
Canto JG. Number of Coronary Heart Disease Risk Factors and Mortality in Patients With First Myocardial Infarction. JAMA 2011;306(19):2120-2127.