Print version ISSN 0021-7557
J. Pediatr. (Rio J.) vol.86 no.4 Porto Alegre July/Aug. 2010
Toward high quality medical care for sickle cell disease: are we there yet?
MD, MS, Assistant member, Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA
Sickle cell disease (SCD), one of the most common single gene disorders in the world, affects approximately 280,000 live births per year worldwide; SCD and thalassemia syndromes together account for 3.4% of all deaths of children younger than 5 years.1 Infants with SCD are particularly at risk of premature mortality from SCD because of the early loss of the filtrative function of the spleen.2,3 This places these vulnerable infants at a high risk of invasive infection by encapsulated organisms, especially pneumococcus. In addition, splenic sequestration is an important SCD-related complication that, if not recognized and treated early in its course, can lead to circulatory collapse and death.4
Despite the increased risk of fatal complications in early life, mortality rates of patients with SCD have significantly declined over the past 4 decades. The most significant decrease has occurred in the first 5 years of life, with a continued shift toward mortality later in life.5 This important trend of increased survival among children can be attributed to simple measures such as early diagnosis, followed by prophylactic therapy and anticipatory guidance. The first and most fundamental of these steps is the implementation of screening programs for newborns. Identification of an at-risk young population has allowed targeted use of prophylactic penicillin and special immunization with Streptococcus pneumoniae, Haemophilus influenzae, and Meningococcus meningitidis vaccinations. These basic public health strategies have positively impacted the overall outcome of pediatric patients with SCD not only in the USA but also worldwide.6,7
Recent statistics from a pediatric cohort from Dallas, TX, USA, shows that the chances of children with SCD dying before 5 years of age are less than 1%.8 This represents a major shift from the 1960s and 1970s, when many children with SCD were not expected to live into adulthood and their risk of sepsis was 20 to 30 times higher than that of the general population.9,10 In this issue of Jornal de Pediatria, Dr. Fernandes and her colleagues have elegantly demonstrated that implementation of an organized, centralized, and well-designed newborn screening program, followed by diligent employment of basic clinical standards, is able to yet again impact and modify the natural course of SCD among young children. Survival rates of children from Minas Gerais, Brazil, who have SCD and are younger than 5 years, are comparable with those from North America, Europe, and the Caribbean, despite the relatively brief existence of Brazil's hemoglobinopathy newborn screening program (Table 1).11
In the future, further improvements are expected in the Brazilian SCD program. Dr. Fernandes's study found that the rate of special immunization (pneumococcal and meningococcal vaccinations) was very low among fatal cases (only 40% of the children who died were immunized), and 31% of patients succumbed to acute splenic sequestration. This underlines the need for a greater effort toward global immunization against encapsulated organisms. In addition, further investment in educating family members about the complications of SCD could have prevented fatal cases of splenic sequestration. A greater emphasis on educating health care providers from primary health care units about SCD is likely to improve the outcome of many more children with SCD. Considering that 58% of the families who lost a child with SCD in Minas Gerais had a monthly income of less than US$ 50.00, the relative low death rate observed in Dr. Fernandes's work shows that adequate diagnosis and medical care can prevent mortality even in the setting of extreme poverty.
Another potential disease modifier that could impact the natural history of SCD and reduce early mortality is hydroxyurea therapy. Hydroxyurea appeared to have prevented deaths among adults with SCD in the United States and Greece.12,13 Given its ease of administration and low cost, hydroxyurea therapy could be adopted and used in developing nations. The feasibility of its use, including the cost of ongoing monitoring of hydroxyurea therapy's toxicity and efficacy, may pose a problem for resource-poor areas of the world, but with adequate planning and some basic infrastructure in place, it is doable. Hydroxyurea therapy has the potential to reduce mortality rates of young children with SCD because of its possible role in organ protection and proven effect in reducing acute vaso-occlusive episodes.14,15
Finally, it is important to note that the creation of an enterprise that will be responsible for successfully diagnosing and treating SCD in the context of an emerging economy requires substantial efforts from its organizers and sustained government support. Despite the natural obstacles to establishing such a medical infrastructure, as well as the substantial low socioeconomic status of most patients, deaths can be prevented and outcomes improved with such an undertaking. The experience in Brazil can serve as an example to many other nations with similar socioeconomic circumstances. As caregivers of SCD, we have come a long way, and although we have not yet achieved the goal of excellence in medical care for all patients with SCD, the road ahead may be successfully traveled.
The author is indebted to Dr. Charles Quinn, MD, for providing additional information about survival from the Dallas Newborn Cohort, and Drs. Winfred Wang, MD and Vani Shanker, PhD for helpful comments on the editorial.
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Correspondence: Conflicts of interest: No conflicts of interest
declared concerning the publication of this editorial.
Jane S. Hankins
St. Jude Children's Research Hospital
262 Danny Thomas St., Mail Stop 800
Memphis, TN 38105 - USA
Conflicts of interest: No conflicts of interest declared concerning the publication of this editorial.