Young adults with premature myocardial infarction: are current SCORE2 thresholds sufficient?

Background Acute Coronary syndrome (ACS) is becoming more prevalent in younger population but risk estimation in young adults remains difficult, as short-term absolute risk was studied in older population. We sought to examine how SCORE2 classifies patients who presented with premature myocardial infarction. Methods The YMIR (Young adults with Myocardial Infarction in Reunion Island) registry included all patients younger than 45 years admitted for ACS in Reunion island between 2016 and 2021. Among those 517, SCORE2 could be calculated in 228 individuals aged 40 years or older without prior cardiovascular disease nor diabetes. Risk categories were interpreted according to ESC 2021 age-specific thresholds. Results Using age-adapted cut-offs for individuals under 50 years-old, 58.8% of patients were classified as high risk (2.5–7.5%), and 0.4% as very high risk (≥7.5%). However, 40.8% were considered low-to-moderate risk (<2.5%) despite subsequently experiencing MI before age 45. (Figure 1) The overall cohort (n = 517) displayed a substantial burden of modifiable risk factors: 68% were active smokers, 35.5% had obesity, 60% had HDL cholesterol below 0.4 g/L, and nearly 20% had diabetes. Overall, 51.6% of patients had LDL-C levels above 1.16 g/L, indicating that more than half exceeded recommended primary prevention thresholds despite their young age. Only 9.4% were receiving statin therapy prior to the acute coronary event. Conclusions Although SCORE2 identifies half of young adults who develop premature MI as high risk, a significant proportion remains classified as low risk despite significant cardiometabolic exposure with the limit that it can only be used for patients ≥40 years old. Implications These findings suggest that reliance on 10-year absolute risk alone may be insufficient in young adults and support complementary strategies such as earlier risk factor screening.