HLA-DRB1 and rheumatoid arthritis: However, a recently published study in a large RA cohort revealed that several other factors, such as genes (for example, HLA-DRB1 shared epitope alleles), RA-specific factors (for example, autoantibodies and use of systemic steroids) and other factors such as hypothyroidism predicted the presence of CVD in RA [44,45].