Autoimmune diseases: Sex and gender evidence in rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis

Abstract Many autoimmune diseases display sex differences in epidemiology, presentation, and prognosis. Rheumatoid arthritis (RA) is three times more common in women and RA is generally more severe in women compared to men. Systemic lupus erythematosus is eight times more common in women and the distribution of lupus-related organ involvement differs by sex. In contrast, ankylosing spondylitis (AS) is more common in men and the clinical presentation of AS differs by sex. In addition, some of the medications used to treat autoimmune diseases have teratogenic effects; appropriate contraception should be included in each patient’s treatment plan. In clinical practice, it is important to consider sex differences in autoimmune diseases, particularly differences in initial clinical presentation and prognosis, because they can influence development of a differential diagnosis and, in established disease, can alter patient counseling regarding expectations for the disease course.