Hydroxychloroquine is associated with a lower risk of polyautoimmunity: data from the RELESSER Registry

Objectives This article estimates the frequency of polyautoimmunity and associated factors in a large retrospective cohort of patients with SLE. Methods RELESSER (Spanish Society of Rheumatology Lupus Registry) is a nationwide multicentre, hospital-based registry of SLE patients. This is a cross-sectional study. The main variable was polyautoimmunity, which was defined as the co-occurrence of SLE and another autoimmune disease, such as...