Abstract
Introduction
The complex interaction between genes and environmental factors contribute to individual-level risk of coronary artery disease (CAD), often resulting in premature CAD. The role for genetic risk scores in premature CAD is still controversial.
Objective
To evaluate the importance of conventional risk factors and of a genetic risk score in younger and older patients with coronary artery disease
Methods
From a group of 1619 pts with angiographic documented CAD from the GENEMACOR study, we selected 1276 pts admitted for ACS and analysed them in 2 groups (group A: ≤50 years, n=491 pts, 87.2% male, mean age 44±4.9 and group B: >50 years, n=785 pts, 75.2% male, mean age 57±4.2). Univariate analysis was used to characterize the traits of each group and we used ROC curves and respective AUCs to evaluate the power of genetics in the prediction of CAD, through a Genetic Risk Score (GRS).
Results
99.3% of the young patients had at least one modifiable risk factor, 18.4% had 2 modifiable risk factors and 75.2% had 3 or more modifiable risk factors. The pattern of risk factors contributing to CAD were different among groups: family history (A: 27.5%, B: 21.4%, p=0.015) and smoking habits (A: 64.8%, B: 42.9%, p<0.001) were more frequent among patients under 50, and traditional age-linked factors like hypertension (A: 58%, B: 75.7%, p<0.001), diabetes (A: 21.6%, B: 38.6%, p<0.001) were more common in the older group. Acute ST-elevation myocardial infarction was more frequent among the young (A: 55.4%, B: 47.4%, p=0.006), as non-ST clinical presentation was higher among elder patients. Regarding angiographic presentation, single vessel CAD was higher in group A (A: 50.3%, B: 40.9%, p<0.001), while multivessel diasease was higher in group B (A: 33.3%, B: 53.9%, p<0.001). At a mean follow-up of 5 years, older patients had a worst prognosis, registering a higher rate of cardiovascular death (A: 4.1%, B: 8.6%, p=0.002) and higher MACE (A: 26.8%, B: 31%, p=0.128),. Adding the genetic risk score (GRS), we achieved only a slight improvement in the AUC for predicting CAD (0.796->0.805, p=0.0178 and 0.748->0.761, p=0.0007 in patients under and over 50, respectively).
Conclusion
Coronary artery disease is not all the same, as premature CAD shares a unique and specific pattern of risk factors, clinical presentation, angiographic severity and prognosis. Genetics should not be used as an excuse to justify premature CAD, as there is frequently more than one potentially reversible risk factor present even in young patients and the additive predictive value of GRS is modest.
Naïve Bayesian Classifier and Genetic Risk Score for Genetic Risk Prediction of a Categorical Trait: Not so Different after all!