OBJECTIVES: Transfusion-dependent β-thalassemia (TDT) is a rare hereditary blood disorder in which patients suffer from chronic anemia and the effects of iron overload due to chronic blood transfusions despite chelation therapy, resulting in significant morbidity and early mortality. The impact of transfusion dependence on chronic complications and their subsequent impact on long-term clinical outcomes is not fully characterized. A model was developed to predict long-term clinical outcomes for patients with TDT treated with standard of care in the United States (US).

METHODS: A Markov cohort model with a lifetime horizon was used to track a cohort of adult patients (mean age at baseline: 18 years) assumed to receive an average of 17 blood transfusions per year until death. Mortality was estimated based on transfusion dependence and the presence of complications including cardiac complications and diabetes. Other complications tracked in the model included liver complications, hypogonadism, and osteoporosis. Model inputs were derived from published literature. Scenario analyses varied the mortality inputs and risks of developing complications each by ±20% to explore their impact on life expectancy in this patient population.

RESULTS: The average modelled life expectancy for adults with TDT in the US was 44 years. Starting from age 18, each patient incurred an average of 443 blood transfusions over the remainder of the lifetime horizon. The most common chronic complications developed over the lifetime horizon in the model were hypogonadism (65%), diabetes (36%), and cardiac complications (31%). Scenario analyses demonstrated that survival estimates were most sensitive to the mortality and risk inputs for cardiac complications.

CONCLUSIONS: Model projections demonstrate that patients with TDT receiving standard of care have a high risk of complications and reduced life expectancy. Innovative therapies that can remove the need for blood transfusions could improve long-term clinical outcomes in this patient population.