Epidemiology of immune thrombocytopenia: study of adult patients at a referral hematology service in Northeastern Brazil.

Immune thrombocytopenia (ITP) is an acquired bleeding disorder observed in the clinical practice. Little is known about its epidemiology in Brazil. The present study was conducted at a hematology referral center which covers a population of over 8 million in 184 municipalities in the state of Ceará. The purpose of this study was to draw a demographic profile of adult ITP patients with regard to sex, age, geographical origin and distribution across the state, and the proportion of secondary ITP. Following ethics committee approval, information was collected with an ad hoc instrument. The sample consisted of 187 adult ITP patients attending the Walter Cantídio University Hospital in 2015. The median follow-up time was 67 months (range: 1 month to 29 years). Female sex (n = 154; 82.35 %) was strongly prevalent in all age brackets, with an overall female/male ratio of 4.7:1. The median age was 41 ± 16.1 with an interquartile range of 29-55.5 years; there was no difference between the genders. Secondary ITP (18/187; 9.6 %) displayed a bimodal distribution and a linear increase between 38 and >68 years of age. The results of this survey on the epidemiology of ITP in Brazil suggest that ethnic and geographical factors may have a great impact on age and sex distribution and on the distribution of secondary ITP.