HLA-DRB1 and rheumatoid arthritis: Although the studies differ in some aspects of the methodology, such as the ESPOIR is a prospective longitudinal study assessing not only clinical variables but also other factors such as HLA-DRB1 genotyping, synovial immune-histologic markers, radiographic progression, work disability, and economic impact of treatment and mortality, both reach similar conclusions regarding the benefits of early intervention in RA using the 6-month time frame [19, 20].