title: Applicability of 2009 international consensus terminology and criteria for immune thrombocytopenia to a clinical pediatric population.
abstract: 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 criteria(Hist) , while only 90.7% could be classified as "newly diagnosed," "persistent," or "chronic" ITP using the criteria(IWG) (P < 0.01). Only 33.7% met criteria(IWG) for severe ITP, whereas 77.4% met criteria(Hist) for severe ITP. A striking difference was that overall response to therapies was lower if the criteria(IWG) were used rather than the criteria(Hist) , 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 criteria(IWG) for refractory ITP.
  
  
  CONCLUSIONS
  Most ITP patients could easily be classified using the 2009 criteria(IWG) . Limitations to applying the criteria(IWG) included absence of treatment response durations, incomplete definition of pediatric "refractory ITP," and exclusion of secondary ITP. Nevertheless, the criteria(IWG) were more clinically relevant given the reliance on definitions based on bleeding and their ability to be applied prospectively. The utility of using the criteria(IWG) within prospective trials remains to be determined.
authors.affiliation: Children's Hospital Boston, Boston, MA, USA. rachael.grace@childrens.harvard.edu
authors.forename: Rachael F
authors.initials: RF
authors.lastname: Grace
authors.forename: Michelle
authors.initials: M
authors.lastname: Long
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Kalish
authors.forename: Ellis J
authors.initials: EJ
authors.lastname: Neufeld
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D032921:Consensus; D005260:Female; D005500:Follow-Up Studies; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data*; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D007155:Immunologic Factors / Q000627:therapeutic use; D007223:Infant; D007391:International Cooperation; D008297:Male; D008499:Medical Records; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000145:classification* / Q000175:diagnosis* / Q000188:drug therapy; D012189:Retrospective Studies; D009626:Terminology as Topic; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D016756:Immunoglobulins, Intravenous; D007155:Immunologic Factors