A Simulation Study Comparing SNP Based Prediction Models of Drug Response

Lack of replication on findings and missing heritability are two of the major challenges in Pharmacogenetics (PGx) studies. Recently developed statistical methods for genome-wide association studies offer greater power both to identify relevant genetic markers and to predict drug response or phenotype based on these markers. However, the relative performance of these methods has not been thoroughly studied. Here, we present several simulations to compare the performance of these analysis methods. In our first simulation, we compared five different approaches: Elastic Net (EN), Genome-wide Association Study (GWAS)+EN, Principal Component Regression (PCR), Random Forest (RF) and Support Vector Machine (SVM). The results showed that EN has the smallest test mean squared error (MSE) and the highest portion of causal SNPs among identified SNPs. In the second simulation, we compared three approaches, GWAS+EN, GWAS+RF and GWAS+SVM. The GWAS+RF has the smallest test MSE and the highest causal percent. In the third simulation study, we compared two cross validation procedures: GWAS+EN versus modified learn and confirm cross validation GWAS+EN. The latter approach demonstrated better prediction accuracy at the expense of greatly increased computational time.