Down Syndrome Abstract
of the Month:
July 2007
Screening for celiac disease in asymptomatic children with Down syndrome: cost-effectiveness of preventing lymphoma.
Swigonski NL, Kuhlenschmidt HL, Bull MJ, Corkins MR, Downs SM.
Pediatrics. 2006 Aug;118(2):594-602.
Dept. of Pediatrics, Indiana Univ. School of Medicine, Indianapolis, Indiana, USA.
Abstract:
BACKGROUND: Studies demonstrate an increased prevalence of celiac disease in persons with Down syndrome, leading some organizations and authors to recommend universal screening of children with Down syndrome. However, many children with Down syndrome are asymptomatic, and the long-term implications of screening are unknown. The complication of celiac disease that leads to mortality in the general population is non-Hodgkin's lymphomas. OBJECTIVES: The purpose of this research in asymptomatic children with Down syndrome was to (1) calculate the number needed to screen to prevent a single case of lymphoma and (2) present a cost-effectiveness study of screening. METHODS: We constructed a decision tree using probabilities derived from the published literature for Down syndrome or from the general population where Down syndrome-specific data were not available. Celiac disease was determined by serologic screening and confirmation with intestinal biopsy. Sensitivity analysis was used to alter probability estimates affecting the cost of preventing lymphoma. RESULTS: Using our baseline values, the no-screen strategy is dominant; that is, screening not only costs more but also results in fewer quality-adjusted life-years. A screening strategy costs more than $500,000 per life-year gained. Screening all asymptomatic children with Down syndrome for celiac disease costs almost $5 million to prevent a single case of lymphoma. CONCLUSION: These analyses do not support the cost-effectiveness of screening, and more data are needed before recommendations to screen asymptomatic children with Down syndrome for celiac disease can be made.
My comments:
The purpose of a screening test is to look for signs of a disease that may not be readily apparent on a physical examination. A good screen should indicate at least 90% of people who actually have the disease and not point at very many people who don't have it. The screen should be easy to perform and should not cost more than the actual tests that confirm the diagnosis. The screen should also have a purpose of finding people who have a disease or condition that requires treatment to avoid illness. In this study, we're looking at the cost of the screening for celiac disease.The observation that celiac disease may appear without any remarkable symptoms is a fairly new one, and the information that children with Down syndrome are more prone to celiac disease is also new. So there is currently no well-developed policy for screening children with DS for celiac disease. To institute a policy for such a screening, the screen needs to fulfill the requirements I outlined above.
The study here looked at several variables and then set up a computer model to determine if the screen is worth doing for children with DS. They concluded that it was not. I could go into a long discussion about how the researchers set up their calculations, but the main factor to look at is that they felt the only important complication of celiac disease is intestinal lymphoma, an uncommon complication that does not appear till the person with untreated celiac disease is in their late 50s or 60s. Since the life expectancy of people with DS was calculated by the researchers as 56 years of age, it is easy to see how their calculations showed no benefit of screening.
My concern as a pediatrician is that we may not currently know the true complications of untreated celiac disease in children with DS, and that is not considered in this study. But the effects of this study will be that the American Academy of Pediatrics will not be including any recommendation to screen for celiac disease in their Health Supervision for Children with Down Syndrome articles.
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