Beta-thalassemia natural history, complications and prognosis

Without regular blood transfusions, affected individuals by major beta-thalassemia typically develop severe anemia and other complications such as pulmonary hypertension, right heart failure, iron overload, infections early in life, while beta-thalassemia intermedia patients would have a variable clinical course, complications, and prognosis. Beta-thalassemia minor subjects would not have significant symptoms, while in some cases might have an increased risk for iron deficiency anemia. Iron overload complications happen in transfusion-dependent thalassemia. The prognosis of beta-thalassemia depends on the severity of the disease and the presence of complications such as iron overload-related complications and cardiovascular disorders.

• Untreated beta-thalassemia can result in significant morbidity, mortality, and diminished quality of life. Patients with non-transfusion-dependent beta-thalassemia (NTD) can develop a wide range of complications in critical organ systems due to ineffective erythropoiesis, hemolysis, and primary iron overload. NTD patients can progress to transfusion-dependent beta-thalassemia (TD) later in life, which further exacerbates the risk of complications and iron overload^[1].
• Untreated thalassemia major patients are at a high risk of developing pulmonary hypertension and right heart failure. The prevalence of these conditions in beta-thalassemia patients depends on the severity of the disease and the adequacy of treatment. Thalassemia major patients who do not receive treatment almost universally develop pulmonary hypertension. On the other hand, thalassemia intermedia patients are more likely to develop pulmonary hypertension compared to treated thalassemia major patients^[2].
• Untreated beta-thalassemia major patients may also experience irreversible bone and organ damage due to iron overload^[3].

Beta-thalassemia is associated with complications such as:

• Hemolytic anemia, chronic microcytic hypochromic anemia
• Iron overload due to chronic hemolysis and transfusion
• Irreversible bone and organ damage secondary to iron overload^[3].
• Oxidative stress, which is mainly caused by tissue injury due to the overproduction of free radicals resulting from secondary iron overload^[4].
• Infections (hepatitis B, hepatitis C, HIV) due to contaminated blood transfusion^[5].

The prognosis of beta-thalassemia depends on the severity of the disease and the presence of complications.

• Beta-thalassemia major: Without treatment, individuals with thalassemia major may experience growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, and skeletal changes. Regular transfusion therapy can lead to iron overload-related complications, including endocrine complications, dilated cardiomyopathy, liver fibrosis, and cirrhosis. Cardiac disease caused by myocardial injury is the most important life-limiting complication of iron overload in beta-thalassemia.
• Beta-thalassemia intermedia: present later in life with moderate anemia and do not require regular transfusions. However, they may experience complications such as hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis, gallstones, painful leg ulcers, and increased predisposition to thrombosis.
• Beta-thalassemia minor: clinically asymptomatic, but some individuals may have moderate anemia^[6].

The prognosis of beta-thalassemia can also be influenced by cardiovascular involvement.

• Parenchymal injury secondary to myocardial iron deposition and immune-inflammatory processes are known to be primary reasons for cardiovascular disorders in patients with thalassemia.
• Early abnormalities in ventricular myocardium can occur in patients with beta-thalassemia, even in those receiving effective chelation therapies.
• Aortic elasticity indices are impaired in patients with beta-thalassemia major, and these parameters may be used to predict cardiovascular complications in asymptomatic patients^[7].

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