Rate of Bleeding-Related Episodes (BREs) in Adult Patients with Primary Immune Thrombocytopenic Pupura (ITP): A Population-Based Retrospective Cohort Study of Administrative Medical Claims Data in the United States (US)
Authors: Cetin Karynsa , Wasser Jeffrey , Wettten Sally , Altomare Ivy 
Published: October 2019

Background: ITP is a rare disorder characterized by low platelet counts and an increased tendency to bleed. The goal of ITP therapy is to treat or prevent bleeding. In ITP therapy trials, ethical considerations require that any patient determined to be at imminent risk of bleeding is treated with any therapy necessary to reduce this risk (“rescue therapy”). Therefore, BREs reported in this setting may not reflect true bleeding rates. Understanding the frequency of both actual bleeding events and/or use of rescue therapy in routine clinical practice could provide additional insights on the real-world burden of this disease.

Methods: Based on administrative medical claims from the MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits Databases in the US, we identified adults diagnosed with primary ITP between 01/01/2008 and 12/31/2012. BREs were defined as ≥1 actual bleeding event (of any severity) and/or rescue therapy use (platelet transfusion, intravenous immunoglobulin [IVIg], anti-D, or IV steroids). The rate of BREs (per person per year) was calculated for the ITP cohort overall and by ITP phase (newly diagnosed: 0 to <3 months; persistent: 3-12 months; and chronic: >12 months) and splenectomy status. Patients were followed from ITP diagnosis until death, disenrollment from the health plan, or 06/30/2013, whichever came first.

Results: Of approximately 67 million adults in the database, we identified 6,651 adults with primary ITP followed for 13,046 person-years (mean age: 52.4 years; 59% female). During follow-up, 3,768 patients (57%) experienced at least one BRE, translating into a rate of 1.08 BREs per person per year (95% CI: 1.06-1.10). Of the total 14,115 BREs, 41% contained bleeding events only; 58% contained rescue therapy only, and 2% contained both. The most common bleeding types were: gastrointestinal hemorrhage, hematuria, epistaxis, and ecchymoses. Intracranial hemorrhage was reported in 74 patients (1.1%). Newly diagnosed and splenectomized patients had higher BRE rates (Table).

Conclusions: We provide current real-world estimates of BRE rates in adults with primary ITP. In our study, the majority of ITP patients experienced at least one BRE, and over half of all BREs were defined by rescue therapy use alone. This demonstrates the importance of examining both bleeding and rescue therapy use to fully assess disease burden and ultimately help determine the relative success of different ITP therapies.

Abstract 202. Table 1 BREs with bleeding only BREs with rescue therapy use only BREs with both bleeding and rescue therapy All BREs Count Rate per person per year (95% CI) Count Rate per person per year (95% CI) Count Rate per person per year (95% CI) Count Rate per person per year (95% CI) Newly diagnosed ITP 2,059 1.29 (1.24-1.35) 2,063 1.30 (1.24-1.35) 126 0.08 (0.07-0.09) 4,248 2.67 (2.59-2.75) Persistent ITP 1,678 0.40 (0.38-0.42) 2,805 0.66 (0.64-0.69) 79 0.02 (0.01-0.02) 4,562 1.08 (1.05-1.11) Chronic ITP 1,984 0.27 (0.26-0.29) 3,272 0.45 (0.44-0.47) 49 0.01 (0.01-0.01) 5,305 0.73 (0.71-0.75) Splenectomized 347 0.42 (0.37-0.46) 618 0.74 (0.69-0.80) 5 0.01 (0.00-0.01) 970 1.17 (1.09-1.24) Non-splenectomized 5,374 0.44 (0.43-0.45) 7,522 0.62 (0.60-0.63) 249 0.02 (0.02-0.02) 13,145 1.08 (1.06-1.09) Overall 5,721 0.44 (0.43-0.45) 8,140 0.62 (0.61-0.64) 254 0.02 (0.02-0.02) 14,115 1.08 (1.06-1.10)

Disclosures

Cetin: Amgen: Employment. Wasser:Amgen: Consultancy. Wettten:Amgen: Employment. Altomare:Amgen: Consultancy.