1.0 - INTRODUCTION
Thalassemia is a complex group of diseases that are relatively rare in the United States but common in Mediterranean regions and South and Southeast Asia. Worldwide, there are 350,000 births per year with serious hemoglobinopathies. In the United States, as a consequence of immigration patterns, occurrence of thalassemia disorders is increasing.
Treatment for thalassemia has dramatically improved. Patients should live full lives with careers and children of their own. Unfortunately, many patients die prematurely or develop morbid preventable complications. Outcomes are far better for patients whose care is coordinated by thalassemia centers (Modell, B., Khan, M., and Darlison, M. Survival in beta thalassaemia major in the UK: Data from the UK Thalassaemia Register. Lancet 355 : 2051–2052. Porter, J.B., and Davis, B.A. Monitoring chelation therapy to achieve optimal outcome in the treatment of thalassaemia. Best Practice & Research: Clinical Haematology 15 : 329–368). The majority of patients are managed in small programs which may not have access to recommended monitoring and treatments. Therefore, an established network of care between thalassemia centers, local providers, and patients is required for optimal treatment of thalassemia patients in North America. Each component of this network should follow the Standards of Care Guidelines and communicate frequently.
All patients should undergo at least an annual comprehensive assessment at a thalassemia center. During such an assessment, recommendations are summarized after consultation with multiple specialists and communicated directly to the primary provider and family. Verbal and written communication between the center and the primary provider should occur at least every six months following the formal annual visit and when there are changes in the patient’s clinical and treatment plan.
A specialty center manages the regular care of at least 20 patients. A specialty program includes a team of thalassemia experts working closely together. This team includes a hematologist, a nurse specialist, a hepatologist, a cardiologist, an endocrinologist, a psychologist, a genetics counselor, a social worker, and a dietitian. A center includes linkage to a thalassemia-oriented bone marrow transplant and fertility service. Within the center, specialty laboratory support includes diagnostic imaging, a hemoglobinopathy reference laboratory, and a clinical research center.
The extent of services provided by a primary or regional program varies. Services may include supervising of regular transfusions and providing necessary medications according to the standards of care. Primary care, including monitoring of growth and general health and—for pediatric patients—liaison with the school, is centralized in the local program. Early recognition and stabilization of acute complications—i.e., sepsis, transfusion reactions, drug reactions, or cholecystitis—require close communication between the primary provider and the family. Twenty-four hour backup consultation should be available through the patient’s designated thalassemia center.
In June 2000, a group of providers developed and finalized the first Standards of Care Guidelines for Thalassemia, with the goal of standardizing the management of care for thalassemia patients throughout the state of California. Since then, significant changes in technology and treatment have developed that required the original guidelines to be updated here.
- 1.1 Common Definitions Used in Thalassemia
- Beta thalassemia disorders result from decreased production of beta globin chains, resulting in relative excess of alpha globin chains. The degree of excess nonfunctional alpha chains is the major predictor of disease severity. Beta0 thalassemia refers to the absence of production of beta globin. When patients are homozygous for a beta0 thalassemia gene, they cannot make any normal beta chains (hemoglobin A). Beta+ thalassemia indicates a mutation that presents decreased but not absent production of beta globin. Thalassemia patients in which one or both of their beta thalassemia mutations are beta+ mutations make some hemoglobin A, and the disorder may be less severe. Beta thalassemia major is a clinical diagnosis referring to a patient who has a severe form of the disease and requires chronic transfusions early in life. Beta thalassemia intermedia is a clinical diagnosis of a patient characterized by a less severe chronic anemia and a more variable clinical phenotype. Alpha thalassemia refers to a group of disorders characterized by inactivation of alpha globin genes. This results in a relative increase in nonfunctional beta globin or gamma globin tetramers and subsequent cell damage. Normally, there are four alpha genes. Absence or non-function of three alpha genes results in hemoglobin H disease, and the loss of all four alpha genes usually results in intrauterine death.