Comparison of three systems for the diagnosis of fetal alcohol spectrum disorders in a community sample.

backgroundIt is estimated that 1%-5% of children in the United States are affected by prenatal alcohol exposure while only a small percentage are so identified in clinical practice. One explanation for this discrepancy may be the way in which diagnostic criteria are operationalized.

methodsTo evaluate the extent to which three commonly used systems for the diagnosis of Fetal Alcohol Spectrum Disorder (FASD) consistently identified children in a community sample, data from the Collaboration on Fetal Alcohol Spectrum Disorders Prevalence (COFASP) study were re-analyzed. In the data set, there were 2325 children with variables necessary to allow diagnosis by three systems commonly used in North America. These systems were (1) that used by COFASP, which is a revised modification of the Institute of Medicine's recommendations, (2) the 4-Digit Code, and (3) the most recent Canadian Guidelines. To determine the degree of association among these classifications, the Fleiss Multirater Kappa measure of agreement was applied.

resultsAmong these three systems, 408 children were classified as FASD, 208 by the CoFASP system, 319 by the 4-Digit Code, and 28 by the Canadian Guidelines. Agreement among the findings from the three systems varied from slight to fair.

conclusionsThese results indicate a lack of consistency in these approaches to FASD diagnosis. Discrepancies result from differences in specifying the criteria used to define the diagnosis, including growth, physical features, neurobehavior, and alcohol-use thresholds. The question of their relative accuracy cannot be resolved without reference to a measure of validity that does not currently exist, and this suggests the need for a more empirically based diagnostic schema.