The Health Outcome
Many states currently are considering expanded newborn screening to cover more than 20 biochemical genetic disorders. Routine newborn screening is required throughout the United States , and started back in 1960 to screen for the single biochemical genetic disorder, phenylketonuria (PKU).(1) Congenital hypothyroidism (CH) was added in the mid-1970s, and with tandem mass spectrometry (MS/MS) newborn screening can now screen for an additional 20+ diseases.(2)
The goal of this study was to analyze the clinical utility of expanded newborn screening while addressing the issues that false-positive results bring to parents. Children with metabolic disorders and their parents' health and development were researched, and the following outcomes were compared between children who were diagnosed with a metabolic disorder through newborn screening and children who were clinically diagnosed: effect on medical outcome, effect on developmental status of the child, impact on resource use and satisfaction with healthcare, and the impact on the family and parental stress. Comparisons were also made between parents of children screened with false-positive results for metabolic disorders and children screened with normal results: interaction with health care professionals, impact on child health, impact on the family and parental stress.(3)
The Finding
Children in the clinically identified group were more likely to be transferred to a neonatal intensive care unit, be hospitalized in the first 6 months of life, have symptoms at diagnosis, have medical complications, have neurological complications, require a gastrostomy tube, require special services, and have lower mental and motor development scores compared to the newborn screened group (all p-values < .05).
Mothers of children in the clinically identified group were more likely to experience distress, to perceive their children as difficult, and to have a dysfunctional parent-child relationship, as measured by the parental stress index (PSI) compared to children in the newborn screened group (all p-values < .001, except parental distress, whose p=.06).
Parents of children identified by newborn screening expressed greater satisfaction with their social support network and were less likely to engage in medico-legal proceedings than parents of clinically identified children (both p-values < .05).
False-positive children were more likely to be hospitalized than the true-negative control group (p=.06). The parents of false-positive children scored significantly higher on the PSI, including the parent-child dysfunction subscale (p<.001).
Public Health Implications
The authors concluded that children identified to have biochemical genetic disorders through expanded newborn screening experience fewer developmental and health problems compared with children whose disorders are identified clinically. These results would have been bolstered had matching been done on the specific disease outcomes since the two groups being compared differed in the types of diseases diagnosed. Issues relating to the penetrance and differing severity of the biochemical disorders as well as information on the percentage of asymptomatic children who were never diagnosed through expanded screening also need to be integrated when analyzing the clinical utility of expanding newborn screening programs.
Issues that should be addressed when deciding whether to expand newborn screening programs include cost-benefit analyses, negative consequences of screening (such as increased parental stress associated with false-positive results), and the total public health burden caused by these rare diseases.
References
- Carlson, M D. Recent advances in newborn screening for neurometabolic disorders. Curr Opin Neurol 2004 April; 17(2) 133-138
- Carpenter KH, Wiley V. Application of tandem mass spectrometry to biochemical genetics and newborn screening. Clin Chim Acta 2002; 332:1-10
- Waisbren, S E, et al. Effect of expanded newborn screening for biochemical genetic disorders on child outcomes and parental stress. JAMA. 2003 Nov; 290(19): 2564 2572
