RESUMO
Most of the world's haemophilia population lives in countries with few medical or financial resources. As such, they cannot easily obtain viral-inactivated clotting product. Many patients are treated with cryoprecipitate made from locally supplied blood. The reasoning for using cryoprecipitate, instead of viral-inactivated products, is based on an unspoken belief that because blood banks can provide reasonably safe products by using modern testing procedures, transmission of HIV and other blood-borne viruses is rare. However, the risk of acquiring a blood-borne infection increases with every exposure, and haemophilia patients treated with cryoprecipitate or fresh-frozen plasma are exposed to hundreds or thousands of donors during their lifetime. The risk that a person infected with HIV will donate blood during the 'window period' is directly related to the incidence of HIV in the country where the donation occurs. To demonstrate the extent of this problem, we devised a model for estimating the risk that a person with haemophilia will encounter HIV-contaminated cryoprecipitate based on the years of treatment and the underlying incidence rate of HIV among blood donors. We applied the model to two countries with different incidence rates of HIV: Venezuela and the United States. We found that a person with haemophilia who receives monthly infusions of cryoprecipitate prepared from plasma of 15 donors over a lifetime of treatment (60 years) is at significant risk of being exposed to HIV. In the United States there is a 2% risk of being exposed to HIV-contaminated blood product, and in Venezuela, the percentage of risk is 40%. Given this degree of risk, medical care providers should carefully evaluate the use of cryoprecipitate except in emergencies or when no viral-inactivated products are available.
Assuntos
Fator VIII/uso terapêutico , Fibrinogênio/uso terapêutico , Infecções por HIV/transmissão , Hemofilia A/virologia , Doadores de Sangue , Contaminação de Medicamentos , Fibronectinas/uso terapêutico , Infecções por HIV/epidemiologia , Infecções por HIV/etiologia , Hemofilia A/complicações , Hemofilia A/terapia , Humanos , Incidência , Modelos Teóricos , Fatores de Risco , Reação Transfusional , Estados Unidos/epidemiologia , Venezuela/epidemiologiaRESUMO
OBJECTIVE: To assess the incremental cost-effectiveness of prophylactic compared with episodic care in boys with severe hemophilia A. SETTING: Eleven U.S. hemophilia treatment centers. METHODS: Charge data from a randomly selected cohort of 70 boys receiving episodic infusions for bleeding events and from all 27 boys receiving infusions prophylactically were collected from documents obtained from the hemophilia treatment centers during a period of approximately 2 years. Published and public sources were used for conversion to cost, lifetime earnings, and earnings losses from disability. A model was constructed for a hypothetical patient from ages 3 to 50 years by means of three infusion scenarios. RESULTS: The cohort receiving prophylactic treatment had fewer bleeding events each year (median, 3 vs 31) but used more concentrate (3323 vs 1015 units/kg per year). Factor VIII concentrate accounted for more than 93% of the cost of both episodic and prophylactic care. Compared with episodic infusion, prophylaxis from ages 3 to 20 years costs $1100 per bleeding event prevented, in comparison with $1380 for prophylaxis from ages 3 to 50 years. The total cost of prophylactic care from ages 3 to 50 years would equal the current total cost of episodic care if the price of the concentrate were decreased by 50%. CONCLUSION: Prophylactic care markedly reduces the number of bleeding events and should prevent joint function impairment, but at substantial cost.
Assuntos
Fator VIII/administração & dosagem , Hemofilia A/economia , Hemofilia A/terapia , Hemorragia/prevenção & controle , Adolescente , Criança , Pré-Escolar , Análise Custo-Benefício , Fator VIII/economia , Hemofilia A/complicações , Hemorragia/economia , Hemorragia/etiologia , Humanos , Lactente , Masculino , Modelos Econômicos , Estados UnidosRESUMO
To determine whether IgG subclass concentrations differed between healthy black and white children, we measured IgG1, IgG2, IgG3, and IgG4 immunoglobulins by enzyme-linked immunosorbent assay in sera from 246 black children aged 6 to 42 months. We then compared these values with the normal values established for 664 white children aged 6 to 60 months. The IgG1, IgG2, and IgG4 subclass concentrations of the black children were lower than those for white children; many of the values were below the 95% confidence limits established for white children: 46 (19%) of 246 IgG2 values and 19 (8%) of 246 IgG4 values for black children were below the normal limits. We compared the geometric mean values for black and white children, as determined for each 6-month age grouping between 6 and 42 months of age; 367 of the 664 white children were less than 42 months of age and were included in this analysis. The geometric mean values for IgG1, IgG2, and IgG4 levels were consistently lower for black children than for white children. The differences were significant for IgG1 subclass values of those children older than 24 months and for IgG2 and IgG4 values of those children older than 18 months. No consistent differences were noted for IgG3 subclass values. We conclude that young black children have lower IgG1, IgG2, and IgG4 serum concentrations than are found in white children. If normal IgG values for white children are used, healthy black children may be erroneously classified as IgG subclass deficient. The mechanism and biologic relevance of these population differences need to be evaluated.