Applicability of 2009 international consensus terminology and criteria for immune thrombocytopenia to a clinical pediatric population

Background Since pediatric immune thrombocytopenia (ITP) is relatively infrequent, comparisons among clinical studies are critical but have previously been limited by differences in terminology. In 2009, an international working group (IWG) developed consensus criteria to enhance comparability in future studies in adults and children. Methods. We performed a retrospective medical record review of all pediatric ITP patients seen at a single children's hospital with a first visit between 2003 and 2010 and ;applied both historical (criteria(Hist)) and IWG (criteria(IWG)) ITP criteria to available clinical data. Results. Among the 505 patients seen for ITP over 7 years, 98% could be classified as acute or chronic ITP using the criteriaHist, while only 90.7% could be classified as newly diagnosed, persistent, or chronic ITP using the criteriaIWG (P < 0.01). Only 33.7% met criteriaIWG for severe ITP, whereas 77.4% met criteriaHist for severe ITP. A striking difference was that overall response to therapies was lower if the criteriaIWG were used rather than the criteriaHist, particularly for IVIG (55.4% vs. 70%, P = 0.02) and rituximab (35.3% vs. 83.3% P = 0.05). Only 2 subjects (0.4%) met the criteriaIWG for refractory ITP. Conclusions. Most ITP patients could easily be classified using the 2009 criteriaIWG. Limitations to applying the criteriaIWG included absence of treatment response durations, incomplete definition of pediatric refractory ITP, and exclusion of secondary ITP. Nevertheless, the criteriaIWG were more clinically relevant given the reliance on definitions based on bleeding and their ability to be applied prospectively. The utility of using the criteriaIWG within prospective trials remains to be determined. Pediatr Blood Cancer 2012; 58: 216-220. (C) 2011 Wiley Periodicals, Inc.