Costs of Managing Chronic Immune Thrombocytopenic Purpura (ITP) in Adults: A Retrospective Analysis.
Authors: Khellaf Mehdi , Eckert Laurent , Poitrinal Priscille , Francesconi Camille , Haddad Albert , Languille Laetitia , Bierling Philippe , Michel Marc , França Lionel Riou , Launois Robert , Godeau Bertrand 
Published: October 2019

Abstract
Abstract 4462

Background and objectives
The treatment of chronic immune thrombocytopenic purpura (ITP) requires therapies which vary considerably in type, duration, and cost. The impact of ITP on resource utilization and direct healthcare costs in France is currently unknown. Yet it is crucial to gain a better understanding of the cost of ITP, particularly in its chronic form, in order to determine the value of new therapies in this therapeutic area. We report here the annual costs in a group of patients with chronic ITP enrolled consecutively and followed for a period of one year in a single French reference center.

Design and Methods
This is a single-center, single-arm, retrospective, observational cohort study in which adult (>18 years) patients with chronic ITP (diagnosed as per ASH guidelines) were enrolled and followed for at least one year. Patients with secondary ITP were excluded. Resource utilization and costs for treatments (drugs and splenectomy) and hospitalization/visits were estimated over a one-year follow-up, from a French public hospital perspective. Costs per patient were estimated (mean), and bootstrapping methods were used to calculate 95% confidence intervals (as cost data are not normally distributed). Healthcare resource utilization was analyzed for the entire population (whole group) and in two subgroups in which patients had a more severe form of the disease. The first subgroup (subgroup 1) included patients who were admitted to the hospital during the one-year study period for ITP treatment, treatment of side effects related to ITP treatment, or bleeding symptoms. Among them, we selected a second subgroup (subgroup 2) in which the severity of the disease required at least one intravenous immunoglobulin (IVIg) infusion during the one-year study period. IVIg treatment is costly and commonly used as a rescue therapy in patients with ITP.

Results
A total of 57 consecutive patients (42F/15M) with a mean age of 48 years (SD: 19) at ITP diagnosis were studied. Mean platelet count at diagnosis was 28 ± 26×109/L. Mean length of ITP duration at the time of inclusion in the study was 3.1 years (SD: 2) and 8 patients had undergone splenectomy. Subgroup 1 included 27 patients (47%) who were admitted to the hospital during the one-year study period (full hospitalization, n=23; and/or day hospitalization, n=8). Among them, 12 patients (21%) received at least one IVIg infusion during the one-year study period and were included in subgroup 2. When severity was not considered (whole group), the total mean cost per patient for the one-year study period was €7,293 [3,369; 13,584]. In subgroup 1, of 27 patients with at least one hospitalization, costs rose substantially, with costs being roughly twice that of the whole group: €15,334 [7,876; 27,459] mean cost per patient. Finally, the most dramatic cost increase was observed in 12 patients who received IVIg (subgroup 2). Costs in this group were more than three times those in the whole group: €26,581 [12,241; 50,578] mean cost per patient. IVIg costs accounted for 50% of the whole group costs and up to 64% of costs when considering patients with the most severe disease.

Interpretation and conclusion
Management of adults with chronic severe ITP is costly in France, with IVIg use being a major cost driver. From a budget payer's perspective, the availability of therapeutic agents that could reduce the need for IVIg and emergency hospitalizations could mitigate the costs of current ITP treatments. As the present study investigated only a limited group of patients from a single center, further research to better understand the likely effect of new therapies on resource utilization and costs is warranted.

Disclosures:
Eckert: AMGEN: Employment. Poitrinal:AMGEN: Employment. Francesconi:AMGEN: Employment. Haddad:AMGEN: Employment. Riou França:AMGEN: Employment. Launois:AMGEN: Employment. Godeau:AMGEN: Consultancy.