Retrospective Review of 524 Cases of Pediatric ITP at An Academic Medical Center: Changes In Treatment of Childhood ITP Between 2003–2010
Authors: Long Michelle , Grace Rachael F. , Kalish Leslie A. , Neufeld Ellis J. 
Published: October 2019

Abstract
Abstract 2510

Background:
Childhood ITP is an immune-mediated disorder characterized by low platelet counts and increased risk of bleeding, but life-threatening bleeding is extremely rare, and 2/3 of childhood ITP cases spontaneously resolve. Thus, studies to discern “best” initial therapy have not been feasible. The choice of observation vs. pharmacologic treatment and among treatments is empirical, varying by clinician and center. Expert consensus statements recommend initial observation but how closely these suggestions are followed is unclear (Provan D, et al. Blood 2010; 115: 168). Our objective for this study was to evaluate a large cohort of ITP patients at a single center for treatment trends.

Methods:
After IRB approval, charts were reviewed from 524 subjects with ITP, identified from Children's Hospital Boston hematology records and from hospital wide ICD-9 billing codes. Only subjects with a first hematology clinic visit from April 2003 through June 2010 were included. Demographic, laboratory, and treatment data were collected. Treatment with “short steroid course” was defined as ≤14 days. Initial observation was defined as ≥7 days from diagnosis without treatment. Remission from ITP on observation was defined as a platelet count ≥ 100,000/uL. SAS 9.3 was utilized for Cochran-Armitage tests for trend.

Results:
Of the 524 subjects, 92 % had primary ITP and 8% had secondary ITP, including Evans syndrome and ALPS. 73% had acute (<3 months) or persistent ITP (<1 year), and 27% had chronic ITP (>1 year duration)(Rodeghiero F, et al. Blood 2009; 113:2386). Median age at diagnosis in those with acute or persistent ITP was 4.4 y (IQR 2–10.1) and with chronic ITP was 10.8 years (IQR 4.4–15.1), p<0.001. 39 (7.4%) subjects experienced Grade IV bleeding, and 6 (1.1%) had Grade V (life threatening) bleeding by the scoring system of Buchanan and Adix (J Pediatr 2002; 141:683). The most frequent first treatments used were: anti-D globulin (anti-D)(40.2%), short steroid course (38%), and IVIG (12%). Of 280 Rh+-subjects who received treatment, 133 (47.5%) received anti-D. Use of anti-D as first line therapy significantly decreased by year from 2003 to 2009 (p for trend<.001). Short course steroid use for initial therapy increased by year over the same time period (p for trend <.001). These changes preceded the recent U.S. FDA-mandated boxed warning regarding hemolysis with anti-D. There was no significant trend in use of IVIG and observation as initial therapy over time. 204 (39%) subjects were initially observed without medications. Of these, 60% went into remission during observation and required no further treatment. 17% of the 204 observation subjects developed chronic ITP and continued observation. 23% (47) of the 204 initially observed later received treatment; in this group, median time between diagnosis and treatment after a period of observation was 1.6 mos (IQR 0.5–9.4 mos). Of the 47 observed patients who were later treated, the most commonly cited reasons for treatment initiation included “thrombocytopenia” (25%), bruising (15%), and lifestyle considerations (i.e. desire to be more active)(14%). The most common reasons subjects received drug therapy rather than observation as a first treatment option were thrombocytopenia (27%), bruising (21%), and active bleeding (13%).

Conclusions:
Within one large ITP center, initial treatment choices changed over the past 7 years. Previously, anti-D was given most frequently, but its use has declined while use of short course steroids increased. IVIG use remained constant. Despite recommendations for observation and data confirming its safety, use of observation has not changed with time and only 39% of patients in our center were initially observed without pharmacologic therapy. The most common reason for taking children off of observation and treating was not bleeding. Inconsistencies in treatment of pediatric ITP exist even within academic centers. Efforts should be made to follow published treatment guidelines.

Disclosures:
No relevant conflicts of interest to declare.