Racial Disparities in Pediatric Immune Thrombocytopenic Purpura.

Immune thrombocytopenic purpura (ITP) occurs in children with an estimated incidence of 5/100,000; however, it is not known whether racial disparities in the incidence of pediatric ITP exist. We hypothesize that because petechiae may go unrecognized in black children the observed incidence of ITP in this race may be less. The purpose of this study was to analyze an established pediatric ITP population at New York Medical College in order to assess whether such disparities exist amongst races and to determine the presenting features of ITP in black children.

Retrospective chart review of 630 pediatric ITP patients diagnosed and treated at New York Medical College from 1985 to 2009 was performed to determine the incidence in various races and to study the presenting features in black children. The patients' race was determined by review of medical records, physician recollection and when necessary by contacting patients by phone. Observed rates of ITP in various races were compared to expected rates given the incidence of ITP and the area's demographic construct. Census of children younger than 19 years residing in the Hudson Valley (Westchester, Putnam, Dutchess, and Rockland counties and Danbury, Connecticut) was obtained from the United States Census Bureau. We used a χ² “goodness-of-fit” test to determine whether the sample distribution differed from the population distribution.

Racial demographics were available for 530 of 630 (84%) ITP patients. The estimated racial demographics of children younger than 19 years residing in the Hudson Valley are as follows: total population, 468,550; 75% Caucasian; 10% Hispanic 10% black; and 5% Asian. Of the 530 identified, 406 (76.6%) were found to be Caucasian, 55 (10%) Hispanic, 36 (7.5%) Black, and 33 (6.2%) Asian. If ITP is detected equally amongst races, one would expect to find 397.5 White patients (observed expected difference [O – E] 8.5 with a residual of 0.426), 53 Hispanic (O - E 2 with a residual of 0.275), 53 black patients (O – E -17 with a residual of -2.335), and 26 Asian (O – E 6.5 with a residual of 1.263). The distribution of our sample over race groups compared with the distribution of the population over race groups had a p-value of 0.063 with the largest contribution due to under-representation of black children in our sample. Of the 36 black children with ITP 18 (50%) were found to present with bruising/petechiae, 4 (11%) presented with a combination of wet purpura and bruising/petechiae, 3 (8%) presented with wet purpura alone, and 11 (31%) were asymptomatic.

The incidence of ITP in black children may be less than in Caucasian, Hispanic, and Asian children.

No relevant conflicts of interest to declare.