Background: As clinicians strive to achieve consensus worldwide on how best to diagnose fetal alcohol spectrum disorders (FASD), the most recent FASD diagnosstic systems exhibit convergence and divergence. Applying these systems to a single clinical population illustrates contrasts between them, but validation studies are ultimately required to identify the best system. Currently, only the 4-Digit Code has published comprehensive validation studies.
Methods: The 4-Digit Code and Hoyme 2016 FASD systems were applied to the records of 1,392 patients evaluated for FASD at the University of Washington to: 1) Compare the diagnostic criteria and tools used by each system, 2) Compare the prevalence and concordance of diagnostic outcomes and assess measures of validity.
Results: Only 38% of patients received concordant diagnoses. The Hoyme criteria rendered half as many diagnoses under the umbrella of FASD (n=558) as the 4-Digit Code (n=1,092) and diagnosed a much higher proportion (53%) as fetal alcohol syndrome/partial fetal alcohol syndrome (FAS/PFAS) than the 4-Digit Code (7%). Key Hoyme factors contributing to discordance included relaxation of facial criteria (40% had the Hoyme FAS face, including patients with confirmed absence of alcohol exposure); setting alcohol exposure thresholds prevented 1/3 with confirmed exposure from receiving FAS/FASD diagnoses; and setting minimum age limits for Alcohol-Related Neurodevelopmental Disorder prevented 79% of alcohol-exposed infants with neurodevelopmental impairment a FASD diagnosis. The Hoyme Lip/Philtrum Guides differ substantively from the 4-Digit Lip-Philtrum Guides and thus are not valid for use with the 4-Digit Code.
Conclusions: All FASD diagnostic systems need to publish comprehensive validation studies to identify which is the most accurate, reproducible, and medically valid.
Background: Laboratory studies confirm prenatal alcohol exposure (PAE) causes growth deficiency (GD). GD has traditionally been a core diagnostic feature of fetal alcohol spectrum disorders (FASD), but was removed from the Canadian and Australian FASD diagnostic guidelines in 2016. This study aimed to empirically assess the clinical role and value of GD in FASD diagnosis.
Methods: Data from 1814 patients with FASD from the University of Washington Fetal Alcohol Syndrome Diagnostic & Prevention dataset were analyzed to answer the following questions: 1) Is there evidence of a causal association between PAE and GD in our clinical population? 2) Is GD sufficiently prevalent among individuals with PAE to warrant its inclusion as a diagnostic criterion? 3) Does GD aid the diagnostic team in identifying and/or predicting which individuals will be most impaired by their PAE?
Results: GD significantly correlated with PAE. GD was as prevalent as the other core diagnostic features (facial and CNS abnormalities). GD occurred in all FASD diagnoses and increased in prevalence with increasing severity of diagnosis. The most prevalent form of GD was postnatal short stature. GD was as highly correlated with, and predictive of, severe brain dysfunction as the FAS facial phenotype. Individuals with GD had a two to three-fold increased risk for severe brain dysfunction. Sixty percent of patients with severe GD had severe brain dysfunction. GD accurately predicted which infants presented with severe brain dysfunction later in childhood.
Conclusions: GD is an essential diagnostic criterion for FASD and will remain in the FASD 4-Digit Code.