Economic burden of beta-thalassemia/Hb E and beta-thalassemia major in Thai children

Beta-thalassemia (β-thalassemia) is a common inherited blood disorder worldwide. Hemoglobin E/β-thalassemia is particularly common in Southeast Asia and the Indian subcontinent, as well as coastal North America, where Southeast Asian immigrants constitute a substantial percentage of the population [1–3]. With a population of 65 million, 7% with a β-thalassemia trait and 17% with an HbE trait, an estimated 35,000 patients are living with β-thalassemia syndrome in Thailand [4]. Hb E/β-thalassemia has a variable severity [5–7].

Studies on the economic burden of β-thalassemia have been reported from the United Kingdom [8], Canada [9], Israel, Taiwan, Sri Lanka [10], and Myanmar [11]. In Thailand, a study on the lifetime cost of homozygous β-thalassemia in children was conducted in 2001, and estimated the direct medical cost of treatment to be 6,660,000 Thai baht, or approximately US$149,899, over a period of 30 years [12]. This cost estimate was based on expert opinion, covering mainly blood transfusion and iron chelation drugs. There is also a study on the cost-benefits of prevention measures [13]. Based on our knowledge, we have not found any cost-of-illness study of thalassemia employing patient-specific cost data covering both direct and indirect costs in Thailand. We therefore conducted a comprehensive study of the cost of Hb E/β-thalassemia.

Unlike thalassemia in European countries, a majority of Thai thalassemia patients represented in this study are of intermediate severity. Most children with severe thalassemia in Thailand are under-treated by international standards [16], as evidenced by pre-transfusion hemoglobin below 7 g/dL. Few received iron chelation, and all but very few patients received adequate iron chelation. The choices of high or low transfusion are individually determined by the treating physician, as well as through compliance of the patient's family. There are differences in the practice of thalassemia treatment. While the proportion of types and severity of thalassemia in children were comparable among the three study sites, one-quarter of patients treated in the medical school received high transfusion, > 40% had high ferritin, and more than half received iron chelation. In contrast, all but one patient at Saraburi received high transfusion, only 20% had high ferritin, and < 5% received iron chelation. It is therefore not surprising that costs are significantly higher at medical centers in Bangkok.

Although this study may have limitations on the number of hospitals included, they do represent three major health service settings: namely, public hospitals, teaching hospitals, and military hospitals. In regard to the representativeness of the patients, based on the proportion of newborn thalassemia (thal): β-thal/Hb E, homozygous β-thal, and Hb H disease constitute 30%, 6%, and 64%, respectively. Life spans of β-thal/Hb E, homozygous β-thal, and Hb H disease patients are estimated as 30 years, 10 years, and 60 years, respectively [20, 21]. The proportion of β-thal/Hb E to homozygous β-thal was 5:1. By comparison, proportions of β-thal/Hb E and homozygous β-thal in this study are 91% and 9%, respectively (Table 1). The proportion of β-thal/Hb E and homozygous β-thal was thus 10:1. Therefore, the mean cost of the samples may not represent that of the population. In addition, we conducted a subgroup analysis. A weighted average technique can be applied to calculate the mean cost of the population [22]. Other studies used cost at charge or incomplete cost items [11, 23, 24]. The cost composition included in this analysis is the most complete, since it covers material cost, labor cost and capital cost, including the cost of patient care and non-patient care activities [25]. However, it is a prevalence-based cost-of-illness study, and therefore does not show the whole picture as an incidence-based or lifetime cost of illness, as do other studies. The lifetime cost of thalassemia is presented elsewhere [8, 9].

Direct medical cost was approximately 60% of the total cost. Among the direct medical costs, iron chelation drugs accounted for 39%. Iron chelation contributes significantly to the cost of treatment. Adequate iron chelation has been shown to reduce the complications related to thalassemia and iron overload, and reduce the cost of treatment for these complications [26]. Proportion of indirect cost would increase if we can capture productivity loss due to a decrease of working capacity. In addition, it would be higher among adult patients who are all in working age with higher number of death. Please see the supplement files for the detail of sensitivity analysis and cost function. (see Additional file 2)

In conclusion, to our knowledge, this is the first time that a complete cost-of-illness study of thalassemia has been performed in Thailand. The results provided the cost of taking care of child patients in a societal perspective, covering direct medical cost, direct non-medical cost, and indirect cost. The average annual cost per patient was US$950. Direct medical cost accounted for 59% of the total cost. The costs were classified by hospital type, thalassemia type, severity, and complication. The effects of blood type and iron chelation drug as cost drivers were quantitatively explored. A cost model was fitted; hospital, health insurance, blood transfusion level, iron chelation drug use, and health insurance were significant predictor variables.