Testing the Feasibility of a Passive and Active Case Ascertainment System for Multiple Rare Conditions Simultaneously: The Experience in Three US States.

BACKGROUND: Owing to their low prevalence, single rare conditions are difficult to monitor through current state passive and active case ascertainment systems. However, such monitoring is important because, as a group, rare conditions have great impact on the health of affected individuals and the well-being of their caregivers. A viable approach could be to conduct passive and active case ascertainment of several rare conditions simultaneously. This is a report about the feasibility of such an approach. OBJECTIVE: To test the feasibility of a case ascertainment system with passive and active components aimed at monitoring 3 rare conditions simultaneously in 3 states of the United States (Colorado, Kansas, and South Carolina). The 3 conditions are spina bifida, muscular dystrophy, and fragile X syndrome. METHODS: Teams from each state evaluated the possibility of using current or modified versions of their local passive and active case ascertainment systems and datasets to monitor the 3 conditions. Together, these teams established the case definitions and selected the variables and the abstraction tools for the active case ascertainment approach. After testing the ability of their local passive and active case ascertainment system to capture all 3 conditions, the next steps were to report the number of cases detected actively and passively for each condition, to list the local barriers against the combined passive and active case ascertainment system, and to describe the experiences in trying to overcome these barriers. RESULTS: During the test period, the team from South Carolina was able to collect data on all 3 conditions simultaneously for all ages. The Colorado team was also able to collect data on all 3 conditions but, because of age restrictions in its passive and active case ascertainment system, it was able to report few cases of fragile X syndrome. The team from Kansas was able to collect data only on spina bifida. For all states, the implementation of an active component of the ascertainment system was problematic. The passive component appears viable with minor modifications. CONCLUSIONS: Despite evident barriers, the joint passive and active case ascertainment of rare disorders using modified existing surveillance systems and datasets seems feasible, especially for systems that rely on passive case ascertainment.

Methods for surveillance of fetal alcohol syndrome: The Fetal Alcohol Syndrome Surveillance Network II (FASSNetII) - Arizona, Colorado, New York, 2009 - 2014.

Surveillance of fetal alcohol syndrome (FAS) is important for monitoring the effects of prenatal alcohol exposure and describing the public health burden of this preventable disorder. Building on the infrastructure of the Fetal Alcohol Syndrome Surveillance Network (FASSNet, 1997-2002), in 2009 the Centers for Disease Control and Prevention awarded 5-year cooperative agreements to three states, Arizona, Colorado, and New York, to conduct population-based surveillance of FAS. The Fetal Alcohol Syndrome Surveillance Network II (FASSNetII, 2009-2014) developed a surveillance case definition based on three clinical criteria: characteristic facial features, central nervous system abnormalities, and growth deficiency. FASSNetII modified the FASSNet methods in three important ways: (1) estimation of a period prevalence rather than birth prevalence; (2) surveillance of FAS among school-age children (ages 7-9 years) to better document the central nervous system abnormalities that are not apparent at birth or during infancy; and (3) implementation of an expert clinical review of abstracted data for probable and confirmed cases classified through a computerized algorithm. FASSNetII abstracted data from multiple sources including birth records, medical records from child development centers or other specialty clinics, and administrative databases such as hospital discharge and Medicaid. One challenge of FASSNetII was its limited access to non-medical records. The FAS prevalence that could be estimated was that of the population identified through an encounter with the healthcare system. Clinical and public health programs that identify children affected by FAS provide critical information for targeting preventive, medical and educational services in this vulnerable population.

Fetal alcohol syndrome among children aged 7-9 years - Arizona, Colorado, and New York, 2010.

Fetal alcohol syndrome (FAS) is a serious birth defect and developmental disorder caused by in utero exposure to alcohol. Assessment of the public health burden of FAS through surveillance has proven difficult; there is wide variation in reported prevalence depending on the study population and surveillance method. Generally, records-based birth prevalence studies report estimates of 0.2-1.5 per 1,000 live births, whereas studies that use in-person, expert assessment of school-aged children in a community report estimates of 6-9 per 1,000 population. The Fetal Alcohol Syndrome Surveillance Network II addressed some of the challenges in records-based ascertainment by assessing a period prevalence of FAS among children aged 7‒9 years in Arizona, Colorado, and New York. The prevalence across sites ranged from 0.3 to 0.8 per 1,000 children. Prevalence of FAS was highest among American Indian/Alaska Native children and lowest among Hispanic children. These estimates continue to be much lower than those obtained from studies using in-person, expert assessment. Factors that might contribute to this discrepancy include 1) inadequate recognition of the physical and behavioral characteristics of FAS by clinical care providers; 2) insufficient documentation of those characteristics in the medical record; and 3) failure to consider prenatal alcohol exposure with diagnoses of behavioral and learning problems. Addressing these factors through training of medical and allied health providers can lead to practice changes, ultimately increasing recognition and documentation of the characteristics of FAS.

Down syndrome and hospitalizations due to respiratory syncytial virus: a population-based study.

OBJECTIVE: To assess the risk estimates for respiratory syncytial virus (RSV) hospitalization in children with Down syndrome (DS) and the clinical features and severity of RSV lower respiratory tract infection (LRTI) in hospitalized children. STUDY DESIGN: Statewide hospitalization data for children with DS for 1995 through 2006 from the Colorado Health and Hospital Association database were combined with birth data from the Colorado Department of Public Health and Environment to obtain population-based estimates of RSV LRTI hospitalization for children with DS in the first 2 years of life. RSV hospitalization data for children with DS at the Children's Hospital Colorado for 2000 through 2006 were used to compare the course and severity of hospitalization of DS LRTI admissions with those of matched control subjects. RESULTS: There were 85 RSV LRTI hospitalizations in 630 children born with DS in Colorado, with 50 having no concurrent underlying conditions identified. Children with DS had a significantly higher risk than did those without DS for being hospitalized with RSV LRTI (OR, 5.99; 95% CI, 6.68-5.38), even in the absence of other underlying conditions (OR 3.5; 95% CI, 3.10-4.12). In the case-control study, children with DS hospitalized for RSV presented more frequently with fever (P = .005), had consolidation reported more often on chest radiography (P = .003), and were given bronchodilator therapy more often during the hospital stay (P = .002). CONCLUSIONS: Children with DS have a higher risk of being hospitalized with RSV LRTI even in the absence of coexisting risk factors. They present more often with fever and more often have radiographic consolidation detected on chest radiography.

Hospitalizations due to respiratory syncytial virus in children with congenital malformations.

Statewide respiratory syncytial virus (RSV) lower respiratory tract infection hospitalization data of Colorado children with congenital malformations was used to estimate the population-based risk and severity of disease of RSV hospitalizations. Spina bifida without anencephaly, cleft palate, lung agenesis or dysgenesis, and biliary atresia were associated with a higher risk of being hospitalized with RSV lower respiratory tract infection and an increased severity of disease when hospitalized.

Screening for autism spectrum disorders in children with Down syndrome: population prevalence and screening test characteristics.

OBJECTIVE: We assessed the prevalence of autism spectrum disorders (ASD) and screening test characteristics in children with Down syndrome. METHOD: Eligible children born in a defined geographic area between January 1, 1996, and December 31, 2003, were recruited through a population-based birth defects registry and community outreach, then screened with the modified checklist for autism in toddlers or social communication questionnaire, as appropriate. Screen-positive children and a random sample of screen-negative children underwent developmental evaluation. RESULTS: We screened 123 children (27.8% of the birth cohort). Mean age was 73.4 months (range, 31-142). Compared to screen-negative children, screen-positive children had similar sociodemographic characteristics but a lower mean developmental quotient (mean difference: 11.0; 95% confidence interval: 4.8-17.3). Weighted prevalences of autistic disorder and total ASD were 6.4% (95% confidence interval [CI]: 2.6%-11.6%) and 18.2% (95% CI: 9.7%-26.8%), respectively. The estimated minimum ASD prevalence, accounting for unscreened children, is 5.1% (95% CI: 3.3%-7.4%). ASD prevalence increased with greater cognitive impairment. Screening test sensitivity was 87.5% (95% CI: 66.6%-97.7%); specificity was 49.9% (95% CI: 37.0%-61.4%). CONCLUSION: The prevalence of ASD among children with Down syndrome aged 2 to 11 years is substantially higher than in the general population. The modified checklist for autism in toddlers and social communication questionnaire were highly sensitive in children with Down syndrome but could result in many false positive tests if universal screening were implemented using current algorithms. Research needs include development of specific ASD screening algorithms and improved diagnostic discrimination in children with Down syndrome. Timely identification of these co-occurring diagnoses is essential so appropriate interventions can be provided.