Cost of Bleeding-Related Episodes (BREs) in Adult Patients with Primary Immune Thrombocytopenia (ITP): A Population-Based Retrospective Cohort Study of Administrative Claims Data for Commercial Payers in the United States

Background: ITP is a rare disorder characterized by low platelet counts, which leads to an increased tendency to bleed and bruise. Previously, we reported real-world estimates of the incidence of BREs in adult patients with primary ITP using a large administrative commercial claims database in the US, where BREs were defined as a bleeding event and/or the use of a rescue or emergency ITP therapy (Cetin et al., Blood 2014: 124 [21]). We found that the majority of ITP patients experienced at least one BRE. To further advance our understanding of ITP disease burden, we expanded on this work by examining the economic impact of the BREs observed in this study.

Methods: The study was conducted using the MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits Databases. Patients diagnosed with primary ITP were identified between the years 2007 and 2012 if they had at least 2 outpatient claims separated by at least 30 days or 1 inpatient claim with ICD-9-CM diagnosis code (287.31) for primary ITP. The occurrence of a BRE, occurring between 2007 and 2013, was defined according to a combination of diagnosis codes and/or procedure codes indicating a form of bleeding, administration of intravenous immunoglobulin, anti-D or IV corticosteroids, or platelet transfusion. For cost estimates, the total reimbursed amount received by the providers (including out-of-pocket costs and reimbursement from insurance) was used. Specifically, for outpatient costs, cost on any records with a BRE-related code (diagnosis or procedure) from the start date of the BRE to (1) the date prior to the start date of the next BRE, or (2) a date followed by three consecutive days without any BRE-related claims, whichever came first, was included. For inpatient costs, cost for all services from the admission date (or BRE start date if not the first BRE during the hospital stay) until the earlier of (1) the date prior to the start date of a new BRE, or (2) the discharge date was counted. All costs were adjusted to 2013 dollars using the appropriate Consumer Price Indices (CPI) (hospital and related services CPI and medical care CPI were used for inpatient and outpatient cost adjustment, respectively). Mean and 95% confidence interval (CI) for BRE costs were estimated and subgroup analyses (splenectomy status and BRE types) were conducted. The differences among subgroups were tested by analysis of variance (ANOVA) at a significance level of 0.05 and the standard errors were clustered at the individual patient level.

Results:

As previously reported, among 6,651 patients with primary ITP, a total of 14,115 BREs were identified. The mean (SD) age was 55(18) years at the start of corresponding BRE and females accounted for 59% of the population. The mean total cost of a BRE was $5,606 (Table 1), with a mean inpatient BRE cost of $41,545 and a mean outpatient BRE cost of $2,046. The cost per BRE was approximately $2,300 higher in splenectomized patients compared with non-splenectomized patients, but the difference was not statistically significant. The cost of BREs with actual bleeding only was $9,591, whereas with solely rescue therapy was $2,652. The cost of BREs that included both bleeding and rescue therapy use was $10,380.

Conclusion:

Our study offers insight into the healthcare expenditures incurred by patients with ITP who experience BREs. Higher costs were found among patients requiring hospitalization and in those using bleeding therapy.

Table 1. Cost of BREs in Adult Patients with Primary ITP

Group	N	Mean	Lower 95% CI	Upper 95% CI	P a
Overall	14,115	$5,606	$5,051	$6,161	<.0001
Inpatient b	1,272	$41,545	$36,822	$46,269
Outpatient c	12,843	$2,046	$1,827	$2,266
Gender					0.0665
Male	5,415	$6,268	$5,359	$7,178
Female	8,700	$5,194	$4,494	$5,893
Age					0.0023
18-34	2,071	$6,629	$5,191	$8,066
35-44	1,948	$6,047	$4,432	$7,661
45-54	2,648	$5,833	$4,640	$7,026
55-64	3,359	$6,423	$5,037	$7,809
65+	4,089	$4,060	$3,263	$4,856
Splenectomy status					0.1948
No	13,192	$5,455	$4,915	$5,995
Yes	923	$7,765	$4,304	$11,225
BRE Type					<.0001
Bleeding & Rescue	261	$10,380	$7,836	$12,924
Bleeding only	5,718	$9,591	$8,313	$10,870
Rescue only	8,136	$2,652	$2,368	$2,935

^a Analysis of Variance (ANOVA)

^b Inpatient group refers to BREs requiring inpatient care and other subsequent patient care in different settings if any

^c Outpatient group refers to BREs only requiring outpatient care