Hospitalizations in Pediatric Patients with Immune Thrombocytopenia
Authors: Lu Z John , Danese Mark D. , Herbert Robert , Eisen Melissa , Deuson Robert 
Published: October 2019

Abstract
Abstract 170

Introduction:
Immune thrombocytopenia (ITP) is a hemorrhagic disorder characterized by low platelet counts, spontaneous bruising, mucosal bleeding, and intracranial hemorrhage. In children ≤ 15 years old, the ITP incidence rate is approximately 2–5 cases per 100,000 person-years, with 30% of such cases considered as chronic ITP, which is characterized by persistently low platelet counts for at least 12 months after initial diagnosis. The disease burden of chronic ITP has not been well studied. Herein, we utilized an all-payer inpatient care database for pediatric discharges in the US to examine resource utilization, costs, and important clinical outcomes in hospitalized children with a diagnosis of ITP. Methods: The 2006 Kids' Inpatient Database (KID) was selected for this analysis. The KID is developed within the Healthcare Cost and Utilization Project (HCUP) sponsored by the federal Agency for Healthcare Research and Quality (AHRQ). Systematic random sampling is used to select 80% of all non-birth pediatric discharges, 10% of all non-complicated births, and 80% of all complicated births from all participating community and non-rehabilitation hospitals for inclusion. The 2006 KID database contains data on over 3 million unweighted discharges collected from over 3,700 hospitals in 38 states. This large sample size enables analyses of relatively rare conditions, such as pediatric ITP. ITP-related discharges were identified with the ICD-9-CM diagnosis code of 287.31, regardless of whether it was the principal diagnosis. We developed national estimates of the following: average total inpatient cost; average length of stay (LOS); incidence rates of costly procedures such as total splenectomy and blood transfusions (through ICD-9 procedure codes); incidence rates of serious complications such as septicemia, bacteremia, intracranial hemorrhage (through hospital DRG codes), and in-hospital death. Hospital charges were converted to costs using hospital-specific cost-to-charge ratios available in the database. In addition, subgroup analyses by the following age groups were conducted: 1 to 5, 6 to 9, 10 to 13, and 14 to 17, as well as by whether the ICD-9 code for ITP was the primary diagnosis or a secondary diagnosis on the discharge summary. Results: Approximately 4,274 (0.26%) of all non-birth-related discharges among patients aged 1–17 were in patients with ITP, including 3,633 identified with ITP as the principal diagnosis and 641 as a secondary diagnosis. The majority of hospitalizations in ITP patients occurred in large, teaching hospitals, and slightly over half were for girls. Close to 50% of the ITP hospitalizations occurred through emergency room admissions or transfers from other hospitals or healthcare facilities. The overall incidence of intracranial hemorrhage among ITP hospitalizations was 0.43%, confirming earlier studies. Total splenectomy occurred in approximately 1 in 25 (4.3%) such hospitalizations. The mortality rate during ITP hospitalizations was 0.38%, compared to 0.23% for all other hospitalizations; the difference was not statistically significant. The average LOS for ITP hospitalizations was shorter than for all other hospitalizations in the KID (2.4 vs. 3.6 days, p < 0.0001), but no significant difference in mean total inpatient costs was noted ($6,869 for ITP vs. $6,515 for all others), indicating that the complexity of hospitalization, and correspondingly the intensity of treatment, might have been greater in patients with ITP. A higher complication rate, greater resource utilization, and total costs were all associated with increasing age, with the oldest pediatric age group (14–17 years) experiencing the highest rate of blood transfusions and total splenectomy, the longest LOS, and the greatest total costs (p < 0.0001 for all). Hospitalizations in which ITP was listed as a secondary diagnosis were associated with significantly greater resource use and total costs compared with those where ITP was the primary diagnosis (p < 0.0001). Conclusion: Although hospitalizations in pediatric patients with ITP were not associated with greater LOS or mortality, they appeared to be associated with a greater intensity of resource use and per-day cost. Older age and ITP as a secondary diagnosis contributed to longer stay, more resource use, and higher total cost during hospitalization.

Disclosures:
Lu: Amgen: Consultancy, Equity Ownership, Research Funding. Danese:Amgen: Consultancy, Research Funding. Herbert:Amgen: Consultancy, Research Funding. Eisen:Amgen: Employment, Equity Ownership. Deuson:Amgen: Employment, Equity Ownership.