Expansion of the New York State Newborn Screening Panel and Krabbe Disease: A Systematic Program Evaluation

摘要

The purpose of this study was to conduct a formal program evaluation of the New York State newborn screening for Krabbe disease (KD), a rare neurological disease with variable onset of symptoms to assess 1) the perceptions of stakeholders 2) KD test characteristics, and 3) actual program costs. Using the CDC Framework for Program Evaluation in Public Health, integration of qualitative and quantitative techniques was used to provide a comprehensive evaluation. Stakeholder input was elicited using semi-structured interviews of medical professionals and parents and content analysis of the interview transcripts identified five themes: Legislative/Political, Unintended Consequences, Knowledge and Science, Communication, and Moral Issues. Finally, cost and charge data were used to calculate the cost of the KD screening program from the perspective of the State. Triangulation of the results provided the conclusions for practice and policy recommendations. Using the data from the State annual reports of 9 positive KD screening results, sensitivity was calculated at 100%, specificity was 99%, positive predictive value was 5%, negative predictive value was 100% and prevalence was 1/100,000 births. However, the State reports did not include the 19 infants with low enzyme activity and mutations that could develop into later onset forms of KD. When these 19 infants were included, sensitivity, specificity, and negative predictive value remained unchanged; however, positive predictive value rose to 15%, and prevalence increased to 3/100,000 births. The total annual cost of the program from the perspective of the State was calculated at $750,652. For parents, the cost calculated from initial newborn screen to neurodiagnostic testing was $2669/family. Since 2006, there have been more than 1,000,000 infants screened for KD in New York State. While the screening has identified four infants with the early infantile form of the disease, there have been 24 others identified with low enzyme activity and mutations that may cause later onset forms of the disease, which are poorly understood. This unexpected finding suggests that newborns may be diagnosed with a disease that may not present symptomatically until adulthood. Unfortunately, the current confirmatory enzyme test and neurodiagnostic tests cannot predict onset of disease or severity of symptoms. In addition, the only available treatment, a cord blood transplant, is irreversible, has a high risk of morbidity and mortality, and long term outcomes have not been studied. While the cost of the program from the perspective of the state is not excessive, cost-effectiveness studies are needed to determine the cost of KD screening from the societal perspective, and should include treatment and follow up costs.