Systemic lupus erythematosus: demographics, prognosis, and outcome.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder with an annual incidence of 50 to 70/million and a prevalence of 500/million population. The highest incidence is observed in women aged 20 to 40 years. The clinical manifestations of SLE are remarkably heterogeneous. Major organ system involvement may occur in the heart, lungs, kidneys, and central nervous system and is responsible for most of the mortality and morbidity caused by the disease. Complications of drug treatment, in particular corticosteroid side effects, contribute to longterm morbidity. The major causes of death are directly related to the disease and include acute vascular neurologic events, renal failure, cardiovascular or pulmonary involvement, infection, and coronary artery disease.