Differing Clinical Characteristics Between Young and Older Patients Presenting with Myocardial Infarction

To date, there has been no detailed study of the risk factors and clinical characteristics of patients presenting with myocardial infarction (MI) at a young age in our region. The purpose of this study was to assess the rate and clinical profile of those presenting with young MI in New Zealand.

We identified a cohort of 1199 patients presenting with acute MI between January 2012 and November 2015 from the Wellington Acute Coronary Syndrome Registry. We compared those presenting with young MI, defined as presentation with MI aged 50 years or younger, to those aged over 50 years.

Myocardial infarction at a young age occurred in 154 (12.8%) patients. Compared to those in the older MI group, the young MI group were more likely to be male (80% vs. 71%, p=0.026), of Maori or Pacific Island ethnicity (21% vs. 10%, p<0.0001), have a higher BMI (31kg/m² vs. 29kg/m², p<0.0001), have a family history of premature coronary artery disease (49% vs. 34%, p<0.0001) and to be current smokers (47% vs. 20%, p<0.001). Young MI patients were less likely to have hypertension, dyslipidaemia and diabetes than the older MI patient population. Within the young MI group 36% had none or only one traditional risk factor for MI, and would have been classified as low risk prior to their index event.

Those with young MI accounted for 12.8% of our cohort and had a different risk factor profile to the older MI group with smoking and obesity being particularly prevalent.