Incidence and prevalence of polymyositis and dermatomyositis in a health management organization in Buenos Aires.

BackgroundPolymyositis (PM) and dermatomyositis (DM) are infrequent diseases. Data on incidence and prevalence are scarce and conflicting. There are no such data in Latin America and in Argentina in particular.ObjectivesWe undertook to examine the incidence and prevalence of PM/DM in the prepaid hea