Please help me understand the STEMI vs. NSTEMI disease burden for those with ACS in the US. How many are killed from a STEMI and NSTEMI heart attack each year in the US?
Precompiled data featuring mortality rates in the United States, as broken down into STEMI and NSTEMI related deaths was not readily available, therefore I have calculated based on available data. 112,575 people were killed in 2017 by a NSTEMI heart attack in the United States, while an average of 48,328.6 people are killed annually by STEMI attacks.
I first researched STEMI, NSTEMI, and unstable angina, which are the three types of heart attack that make up acute coronary syndrome. Then I searched government databases, scientific journals, and trusted medical sites in order to find up-to-date information about the mortality rates of each type of myocardial infarction. There is limited data collected about each type separately within the United States. Up-to-date mortality rates specifically involving the umbrella of acute coronary syndrome are similarly difficult to find. As such, I have found recently published studies involving slightly older information, for instance, a 2017 study done on STEMI that collected data from 2003-2010. I have then triangulated data to find the estimated mortality rates, which is explained in detail below.
ST elevation myocardial infarction, or STEMI, is a heart attack that is caused by a complete blockage in an artery in the heart. Patients presenting with a full-blown heart attack from STEMI, which is caused by lack of blood flow long enough to begin to kill the muscle tissue, require CPR and defibrillation to restore a normal rhythm to their heartbeat. There are many early symptoms of a STEMI heart attack, such as dizziness, nausea, chest pain, or a general feeling of doom or anxiety. Unfortunately, these symptoms are often brushed off by the patient as something smaller and non-threatening, causing essential care to be delayed. The amount of time the blockage exists is directly related to the odds of survival. Therefore, early detection and treatment are vital for patient prognoses.
The most recent US study on mortality due to STEMI, published in July 2017, involved patient data collected from 2003-2010 from hospitalized patients. According to the study, 1.99 million patients over 18 years of age were diagnosed with STEMI throughout the eight-year span. Of those, there was a roughly 17% in-hospital mortality rate. Using a desk calculator to multiply 1.99 million by 17%, we can estimate that 338,300 people died from STEMI between 2003 and 2010. In order to find the mortality rate for one year, I have divided 338,300 by 8 years, which equals 42,287.5 deaths on average per year. One study performed in January 2017 concluded that the mortality rate of females was higher than that of males that presented with STEMI.
The overall length of stay for STEMI patients in the hospital averaged 5 days, and the consumer-price-index adjusted hospital costs reached roughly $39,717 on average between 2003 and 2010.
Non-ST elevation myocardial infarction, or NSTEMI, happens when an artery is partially blocked, as opposed to fully blocked as with a STEMI. Slightly less severe, NSTEMI intervention can be delayed up to 72 hours, barring circumstances that put the patient at higher risk. Although the studies are controversial, earlier intervention may lower mortality by as much as 87% for low-risk patients.
A July 2016 study shows that incidences of NSTEMI have increased exponentially since 1994 when 19% of heart attacks fell under this type. In 2006, the percentage rose to 59% and continues to climb. This rise is concurrent with a consistent drop in STEMI related heart attacks. According to a November 2017 study, the in-hospital mortality rate for NSTEMI patients averaged 19%, which could be lowered significantly with surgery or other invasive management. Hospital stays could also be lessened by close to 7 days with the use of the invasive procedures.
According to the CDC, roughly 790,000 people have heart attacks every year in the United States. In 1990, 14.2% of all heart attacks were NSTEMI. In 2006, it had risen to 59.1%, and in 2011 it was reported to be 68.6%. By plotting these years and percentages on a graph and assuming a roughly linear progression, we can estimate the percentage in 2014-2015 would be around 75%.
I have calculated that 75% of 790,000 is 592,500 NSTEMI heart attacks. The mortality rate of NSTEMI patients is 19%. Therefore, 19% of 592,500 is 112,575 deaths per year from NSTEMI related heart attacks.
STEMI heart attacks account for approximately 42,287.5 deaths per year, while NSTEMI deaths count for 112,575 deaths per year in the United States.