Characterizing a Population with Severe Manifestations of Sickle Cell Disease Using U.S. Real-World Evidence

Background Sickle cell disease (SCD) is a monogenetic disorder, with 300,000 to 400,000 infants born annually with the disease around the world (Kato et al, Nat Rev Dis Primers 2018). SCD is a progressively debilitating and life-threatening disease characterized by hemolytic anemia, painful vaso-occlusive events (VOEs) and persistent vasculopathy that result in significant morbidity, poor quality of life and early mortality. There is significant heterogeneity in clinical manifestations of SCD, given that vaso-occlusion and hemolysis-associated endothelial dysfunction may manifest in any tissue or organ. Severely affected patients may experience a diverse set of complications (Kato et al, Nat Rev Dis Primers 2018). Given the limited research to date in this area, the objectives of this real-world, retrospective study were to 1) identify and describe severely debilitating clinical complications experienced by patients with SCD in the U.S. and 2) examine rates of associated co-morbidities for this cohort. Methods A retrospective cohort analysis was undertaken utilizing patient-level, de-identified administrative claims data from the Truven Health U.S. MarketScan® Commercial, Medicare Supplemental, and Medicaid Multi-State Databases, for the period from January 1, 2010 to September 30, 2016. SCD patients were identified based on: ≥ 2 separate dates during study period with a medical claim having a SCD diagnosis (based on set of relevant ICD-9 or ICD-10 CM codes) and included in analyses if they had ≥ 2 years of follow-up with continuous plan enrollment. Treatment approaches and clinical outcomes were defined using a pre-specified list of relevant diagnosis and treatment codes. Commonly identified characteristics of severe SCD were assessed for each patient during their 1st 2 years of continuous enrollment during study period. These included 1): having frequent (i.e. ≥ 4) VOEs [i.e. sickle cell crises either distinct from acute chest syndrome (ACS) or unspecified] that require emergency room care or hospitalization, 2) stroke or history of stroke, 3) receiving chronic red blood cell (RBC) transfusions, or 4) ≥ 1 medical encounters for ACS. Results A total of 18,740 patients with SCD (56% Female; 61% from Medicaid database; 75% Black [only reported in Medicaid sample]) met the study criteria. Nearly 60% of the cohort were Conclusions Based on this contemporary real-world evidence from the U.S. setting, a substantial proportion of patients with SCD experience a diverse set of severely debilitating complications of the disease, as well as other co-morbidities associated with the disease. The high rate of comorbidities across all age groups and overrepresentation of patients younger than 30 years of age (relative to age distribution of general U.S. population) indicate that patients with SCD still experience significant morbidity and early mortality with current standard medical care. Given the notable heterogeneity of the clinical manifestations of SCD, future treatment approaches should address the root cause of the disease. Disclosures Paramore:bluebird bio: Employment, Equity Ownership. Kong:bluebird bio: Consultancy, Research Funding. Minegishi:bluebird bio: Employment, Equity Ownership. Shi:bluebird bio: Employment, Equity Ownership.