Reclassification of SIDS cases—a need for adjustment of the San Diego classification?

A study was undertaken reclassifying cases of sudden infant death syndrome (SIDS) taken from two geographically separate locations utilizing the San Diego definition with subclassifications. One hundred twenty-eight infant cases were examined from files at Forensic Science South Australia in Adelaide, SA, Australia over a 7.5-year period from July 1999 to January 2007. Thirty-one cases (24%) had initially been diagnosed as SIDS and 30 (23%) as undetermined while 67 (52%) had an explainable cause of death. After reclassification, the number of SIDS cases had increased to 49 of the 128 cases, now representing 38% of the cases; category IB SIDS constituted 10 (20%) and II SIDS 39 (80%) of the SIDS cases. No cases were classified as IA SIDS. Two hundred eighteen infant cases were identified from the files of the Department of Forensic Medicine, Aarhus University, Denmark over a 16-year period from 1992 to 2007. Eighty-two (38%) were originally diagnosed as SIDS, 128 (59%) with identifiable causes of death, and 8 (4%) as unexplained. After review, 77 (35%) cases were reclassified as SIDS, a decrease of 6%. Twenty (26%) infants were classified as category IB SIDS and 57 (74%) as II SIDS. None of the cases met the criteria for IA SIDS. Problems arose in assessing cases with failure to thrive, fever, and possible asphyxia. Modifications to the San Diego subclassifications might improve the consistency of categorizing these cases.