Linking Multiple Data Sources in Fetal Alcohol Syndrome Surveillance -- Alaska

Although fetal alcohol syndrome (FAS) is a major preventable cause of mental retardation in the United States (1), surveillance for this problem is subject to at least five constraints: difficulty in identifying the syndrome at birth (2); the subjective nature of the diagnosis; variability in the severity and type of conditions associated with FAS; age-specific variations in the expression of the phenotype; and the lack of specificity in the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code for FAS. Previous studies have documented high rates of FAS among American Indians and Alaskan Natives (ANs) (3,4). To better ascertain cases of FAS in Alaska and to determine the prevalence of this problem among ANs, the Alaska Department of Health and Social Services (ADHSS), the Indian Health Service (IHS), and CDC linked and analyzed data from state sources (i.e., birth and death certificates and Medicaid claims), an IHS case file, and a private pediatric practice case file. This report summarizes the findings from this analysis and presents a preliminary minimum FAS prevalence rate for ANs.

Potential cases were identified in the state data sources using an FAS check box on birth certificates filed from 1989 through 1990, from Medicaid claims filed from 1989 through 1990 using ICD-9-CM code 760.71 (alcohol affecting fetus or newborn via placenta or breast milk), and from death certificates issued during 1977-1990 using ICD-9 code 760.7 (noxious influences affecting fetus or newborn via placenta or breast milk). The IHS case file consisted of patients in whom FAS was diagnosed or who were designated as having fetal alcohol effects (FAE) by a physician during 1985-1992. The pediatric case file consisted of patients examined from 1990 through 1992 by a large pediatric practice, which maintains a computerized case file of children exposed to alcohol in utero or who had been evaluated for FAS or FAE. A case of FAS was defined as a patient meeting five criteria: 1) prenatal alcohol exposure or a maternal history of alcohol abuse, 2) FAS noted by a physician, 3) one or more characteristic FAS facial features, 4) growth deficiency (i.e., prenatal or postnatal height or weight less than or equal to 10th percentile for age), and 5) central nervous system (CNS) impairment (5).

A total of 348 persons were identified; medical records were available for 323, of whom 83 met all five criteria and were considered to have FAS (Table 1). Twelve (14%) persons were identified by more than one data source. The average age (as of December 1992) of persons with FAS was 8 years (range: 0-19 years); 46 (55%) were male. The average age at the time of diagnosis was 3 years; 47 (57%) case-patients had a chart mention of FAS as early as the first year of life. For 49 (59%) case-patients, FAS was diagnosed by a dysmorphologist. Fifty-four (65%) were either adopted or in foster care. Seventy-five (90%) of the case-patients were ANs.

The most prevalent facial features were short palpebral fissures (80%), long and flat philtrum (69%), thin upper lip (51%), and hypoplastic midface (45%). Two or more facial features were noted in 92% of the cases. The most prevalent CNS impairments included developmental delay (69%), microcephaly (41%), speech or language delay (35%), and short attention span (28%). Most (68%) had low birthweights ( less than 2500 g), but because of the high percentage of preterm deliveries (54%), only 46% were small for gestational age (i.e., less than or equal to 10th percentile).

Based on these preliminary data, the minimum FAS prevalence rate for ANs was 2.1 per 1000 live births during 1978-1991 (Table 2). Prevalence estimates were calculated only for ANs because ascertainment was considered incomplete for other racial/ethnic groups.

Reported by: M Bergeson, MD, Tanana Valley Medical Center, Fairbanks; D Ingle, E McKenzie, K Pearson, MSPH, A Zangri, MS, JP Middaugh, MD, State Epidemiologist, Div of Public Health, S Perry, S Cassidy, Div of Alcoholism and Drug Abuse, Alaska Dept of Health and Social Svcs. S Clarren, MD, Div of Congenital Defects, Univ of Washington, Seattle. Alaska Area Native Health Svc, Indian Health Svc, Anchorage. Div of Field Epidemiology, Epidemiology Program Office, and Div of Birth Defects and Developmental Disabilities, National Center for Environmental Health, CDC.

Editorial Note

Editorial Note: The findings in this report indicate that multiple data sources are required to ascertain cases of FAS. For example, in Alaska, the state data sources contained only three (19%) of the 16 cases identified within the pediatric practice and birth certificates identified only two (15%) of the 13 case-patients born with FAS in 1989 and 1990. Although the FAS Study Group of the Research Society on Alcoholism does not require evidence of alcohol exposure in the diagnosis of FAS (5), a history of maternal alcohol abuse or prenatal alcohol exposure was used in the case definition of this report to further ensure that the persons identified had FAS.

The lower rate of FAS for the most recent birth years may reflect incomplete case ascertainment in those birth cohorts rather than an actual temporal decline in the rate of FAS among ANs. In addition, although the true number of prevalent FAS cases in Alaska is unknown, the count presented in this report probably underestimates the total number. Cases were underascertained for at least three reasons. First, the presence of conditions associated with FAS (i.e., facial features and maternal alcohol use) are generally underreported in medical charts (2). Second, medical charts were not always available directly from the source of the Medicaid billing. Third, because of limited resources, data from only one pediatric practice were included.

The large proportions of FAS cases in the IHS case-file and diagnosed by a dysmorphologist reflect the efforts of IHS to ascertain and treat children who have been affected by prenatal alcohol exposure.

Approaches to improve surveillance and increase ascertainment of FAS cases in Alaska include identifying FAS cases from additional private physician practices and patient-care information systems in additional hospitals throughout the state. These efforts should produce a more accurate estimate of the prevalence of FAS, which is essential for evaluating activities to prevent FAS in Alaska.

References

1. Abel E, Sokol RJ. Incidence of fetal alcohol syndrome and economic impact of FAS-related anomalies. Drug Alcohol Depend 1987;19:51-70.

2. Little BB, Snell LM, Rosenfeld CR, Gilstrap LC, Gant NF. Failure to recognize fetal alcohol syndrome in newborn infants. Am J Dis Child 1990;144:1142-6.

3. May AM, Hymbaugh DJ, Aase JM, Samet JM. Epidemiology of fetal alcohol syndrome among American Indians of the Southwest. Soc Biol 1983;30:374-87.

4. Ch¤vez GF, Cordero JF, Becerra JE. Leading major congenital malformations among minority groups in the United States, 1981-1986. In: CDC surveillance summaries (July). MMWR 1988; 37(no. SS-3):17-24.

5. Sokol RJ, Clarren SK. Guidelines for use of terminology describing the impact of prenatal alcohol on the offspring. Alcoholism: Clinical and Experimental Research 1989;13:597-8.

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