Analysis of the Impact and Burden of Illness of Myelofibrosis in the US

Myelofibrosis (MF) is a Philadelphia chromosome–negative myeloproliferative neoplasm. Common disease manifestations include bone marrow failure, enlarged spleen due to extramedulary hematopoiesis (splenomegaly), debilitating symptoms including fatigue, night sweats, pruritus, early satiety, abdominal pain and discomfort, and marked decrement in patient's quality of life (QoL). Decreased survival is a hallmark of the disease as a result of infections, bleeding and leukemic transformations. There are no recent literature estimates looking at clinical and economic burden of illness of this rare disease. The objective of this study was to describe patient demographics, prevalence, comorbidities, utilization and costs for MF using real-world data.

The US IMPACT® insurance claims database was used to retrospectively identify unique patients with any MF (including all primary and secondary MF cases) between 1/1/08 and 12/31/10. The IMPACT database is a fully de-identified, HIPAA compliant national database that captures the complete medical history for over 100 million managed-care individuals, including patient demographics, disease description, laboratory results, details of medical, pharmacy, outpatient, and inpatient claims.

These databases can track patients longitudinally over multiple years, are linked at the patient level by a unique identifier that is consistent across services, health plans, and time and are representative of the US population. ICD-9-CM codes were used to identify MF. The Charlson Comorbidity Index (CCI) was employed to assess overall comorbid disease status. Enrollment was restricted to those with full year of medical and pharmacy benefit. Control group was age and gender matched but without any diagnosis of myelofibrosis. Medical costs include inpatient, outpatient and emergency room cost.

In 2010, 433 patients with MF (mean age 60, 50% female) were identified from about 12 million enrollees. This corresponds to an age-adjusted prevalence of 5.4 per 100,000 patients. Compared with age-gender matched control patients, MF patients had higher overall comorbidities (mean CCI of 2.1 vs. 0.9), were hospitalized more often (34% vs. 11%), had higher number of average hospital days (7 vs. 1 day), and had more outpatient office visits (58 vs. 22) in 2010. Accordingly, MF patients incurred much higher average annual cost ($54,168 vs $10,203) driven by both medical ($45,646 vs $7,987) and pharmacy ($8,523 vs $2,216) cost. Over a period of 3 years, annual cost of MF ranged from $54,000-$68,000. The utilization rate and total cost in each of conditions were significantly higher than those of their matched patients in each of the three years.

Myelofibrosis is associated with a significant burden of illness. Patient with MF incurred about five times healthcare expenditure than those in the control group. Our study indicates that MF-associated medical resource utilization and the corresponding expenditures for those services are substantive. Continued efforts in the development of more efficacious treatments for myelofibrosis are needed in order to reduce the burden of illness associated with this disease.

Wang:Sanofi: Employment, Equity Ownership. Mehta:Sanofi: Employment. Iqbal:Sanofi: Employment, Equity Ownership. Mesa:Incyte: Research Funding; Lilly: Research Funding; Sanofi: Research Funding; NS Pharma: Research Funding; YM Bioscience: Research Funding.