Modifiable Risk Factors in Young Adults With First MI

Study Questions:

What is the prevalence of modifiable risk factors (RF) during a first acute myocardial infarction (AMI), sex/race differences, and temporal trends in young adults in the United States?


A retrospective cohort analysis was conducted in the US National Inpatient Sample (NIS) for years 2005 and 2015, to identify adults 18-59 years of age hospitalized for a first AMI. Prevalence rates; race and sex differences; and temporal trends of hypertension, diabetes mellitus, obesity, smoking, dyslipidemia, and drug abuse were analyzed in these patients.


The analysis included 1,462,168 young adults with a first AMI (mean age 50 ± 7 years, 71.5% men, 58.3% white), of whom 19.2% were 18-44 years of age and 80.8% were 45-59 years of age. In the 18- to 44-year-old group, smoking (56.8%), dyslipidemia (51.7%), and hypertension (49.8%) were most prevalent, and 90.3% of patients had ≥1 RF. In the 45- to 59-year-old group, hypertension (59.8%), dyslipidemia (57.5%), and smoking (51.9%) were most prevalent, and 92% of patients had ≥1 RF. Significant sex and racial disparities were observed in the prevalence of individual RFs. Women had a higher prevalence of diabetes mellitus, hypertension, and obesity, and men had a higher prevalence of dyslipidemia, drug abuse, and smoking. The prevalence of all RFs increased temporally except for the rate of dyslipidemia, which decreased more recently. Trends were generally consistent across sex and racial groups.


During a first AMI in young adults in whom preventive measures are more likely to be effective, modifiable RFs were highly prevalent and progressively increased over time. Significant sex and racial disparities were observed for individual RFs.


NIS is derived from the US Healthcare Cost and Utilization Project sample of 20% of inpatient admissions from acute care hospitals. The strength of the data is the sample reflecting geographic regions, hospital teaching status, ownership, and bed size, and ability to evaluate trends. Amongst the limitations of the NIS is the total reliance on accuracy of discharge coding for AMI and risk factors without clinical exam (blood pressure, body mass index), laboratory testing (fasting blood sugar, lipids), or treatments, and reliance on patients for RF diagnosis. In this study, race was not available in 20% and Black and Hispanic patients were under-represented for the United States. While temporal trends should be reliable unless protocols for coding changes, the NIS would underestimate the percentage of those with modifiable RFs. The study suggests the US efforts for primordial and primary prevention for atherosclerotic heart disease have not impacted a very important group. This was highlighted in the VIRGO study of young men and women ages 18-55 years with an AMI (Leifheit-Limson EC, et al., J Am Coll Cardiol 2015;66:1949-57). Despite having significant cardiac risk factors, only one-half believed they were at risk for heart disease before their event.

Keywords: Acute Coronary Syndrome, African Americans, Diabetes Mellitus, Dyslipidemias, Hispanic Americans, Hypertension, Inpatients, Myocardial Infarction, Obesity, Prevalence, Primary Prevention, Risk Factors, Sex Characteristics, Smoking, Substance-Related Disorders, Young Adult

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