The Clinical and Direct Medical Cost Burden of Splenectomy among Managed Care Patients with Chronic Immune Thrombocytopenic Purpura (ITP).

Background: ITP is a serious chronic disease involving increased platelet destruction and impaired platelet production. Corticosteroids (CS) are used most commonly to treat ITP and are associated with reduction in quality of life. Splenectomy is used less frequently but is a bigger cost driver. Improved therapies for ITP are needed in view of these compromises.

Objective: A retrospective database analysis assessed clinical and economic burdens of ITP in a managed care population, focusing on CS use and splenectomy.

Methods: Patients with a diagnosis of ITP (ICD9-CM code 287.3) between July 1, 2000, and December 31, 2003, were included if they had continuous health plan enrollment 6 months prior to and 12 months after index ITP diagnosis, were aged ≥18 years, and had any ITP-related treatment. This analysis used data from the PharMetrics Integrated Medical and Pharmaceutical Database, which includes data on diagnoses (ICD-9-CM format), procedures (CPT-4 and HCPCS formats), prescriptions (classified by NDC and AHFS), amounts paid and charged, and dates of service for all claims from >45 million patients participating in 82 different managed care plans (80% commercial, 3% Medicaid, 1.7% Medicare Risk, with the remainder “other”).

Results: A total of 770 patients met the study criteria. The mean age was 43.2 years (±14.9) and females accounted for approximately 64% (n=489) of patients. A majority of patients (n=632, 82%) had at least one claim for CS therapy during the 12-month follow-up, and 93% (n=718) received CS for an average of 59.2 (±90.8) days during the 18 months surrounding the index diagnosis; 12% of patients (n=90) received splenectomy within 12 months of index diagnosis. The average time from ITP diagnosis to splenectomy was 119 days (±97). The average annual cost of care per patient was $23,420, with 43% attributable to inpatient hospitalizations. Splenectomized patients incurred an average annual cost of care of $48,424 (±$62,034), compared with $20,110 (±$45,466) for nonsplenectomized patients. Inpatient hospitalizations were the primary cost driver in patients who had undergone splenectomy (39.6%) as well as in those who had not (43.8%). Total health care costs were higher 14 days postsplenectomy ($12,839) versus 14 days presplenectomy ($7,176); this was consistent for inpatient costs ($6,988 vs $4,708), outpatient costs ($834 vs $631) and other combined costs ($4,623 vs $1,178). Almost 90% of splenectomized patients also received CS; this percentage was also greater at 14 days postsplenectomy (48.9%) compared with 14 days presplenectomy (30%). Anti-rhesus D (anti-D) immunoglobulin was also administered more frequently post- versus presplenectomy (8.9% vs 1.1%); this is potentially important, as average annual costs were higher ($32,268 ± 43,704) for patients with anti-D rescue therapy than for those without ($21,718 ± 48,494).

Conclusions: Splenectomized patients (n=90) were nearly 2.5 times more costly than nonsplenectomized patients (n=680), incurring almost $28,000 greater costs, and also showed increased CS use after versus before splenectomy. Additional subanalyses are underway to assess impact of treatment-specific costs in this ITP patient population. Prospectively designed studies are needed to reevaluate standards of care for ITP and long-term patient outcomes as new treatments for ITP are developed.