OBJECTIVES: Sickle cell disease (SCD) is a rare hereditary blood disorder with severe symptom burden including vaso-occlusive crises (VOCs) and chronic end-organ damage. VOCs are associated with an increased risk of complications and death. A model was developed to predict long-term clinical outcomes for patients with SCD experiencing recurrent VOCs in the United States (US).

METHODS: We developed a Markov cohort model with a lifetime horizon to track an adult cohort (mean age at baseline: 18 years) who experienced an average of 4 VOCs per year across their lifetime. Mortality was estimated based on the following: disease impact from SCD, occurrence of VOCs, and SCD-related complications including acute chest syndrome, stroke, chronic kidney disease, pulmonary hypertension, and heart failure. Model inputs were derived from published literature. Scenario analyses were conducted to explore the impact of annual number of VOCs (2 to 8) and mortality inputs for VOC and SCD-related complications (±20%) on model outcomes.

RESULTS: The average modelled life expectancy for adults with SCD with recurrent VOCs in the US was 54.8 years. Starting from age 18, patients experienced an average of 147 VOCs over the remainder of the lifetime horizon. The most common chronic complications developed over the lifetime horizon in the model were avascular necrosis (68%), neurocognitive impairment (67%), and chronic kidney disease (52%). Scenario analyses demonstrated that survival estimates were most sensitive to mortality inputs for chronic kidney disease and heart failure. When the average number of annual VOCs was varied from 2 to 8, life expectancy was reduced from 56.6 to 51.3 years.

CONCLUSIONS: Model projections demonstrate that patients with SCD with recurrent VOCs have a reduced life expectancy and experience substantial disease burden. Treatments that can minimize the occurrence of VOCs and reduce disease complications could improve survival and long-term outcomes in this patient population.