The San Diego definition of SIDS: practical application and comparison with the GeSID classification

The new definition of the term sudden infant death syndrome (SIDS) and the criteria introduced in San Diego for the subclassification of cases have been used to re-classify the first 100 consecutive cases of sudden and unexpected infant deaths that were registered with the German SIDS study (GeSID). Although there are 30 different variables that have to be considered in the general and stratified sections of the San Diego definition, it is practical, in particular, as an international standard to perform scientific studies. The comparison of the San Diego definition and the classification used for GeSID shows similarities in the methods but differences in the criteria used. Nevertheless, the numbers of cases classified as SIDS and borderline SIDS are similar (San Diego n=69, GeSID n=74). The SIDS IA criteria of the San Diego definition were not fulfilled by any case because metabolic screening and vitreous chemistry were not included in the GeSID investigation scheme. An important advantage of the San Diego definition is the introduction of the category of unclassified sudden infant death, which includes cases for which no autopsy was performed. This demonstrates that such cases cannot be classified as SIDS. In conclusion, we recommend the universal acceptance and use of the San Diego SIDS definition.