Investigation of sudden unexpected deaths in infancy

To compare the clinical characteristics associated with sudden infant death syndrome (SIDS) and explained sudden unexpected deaths in infancy (SUDI).Three year population based, case control study with parental interviews for each death and four age matched controls.Five regions in England (population,17 million; live births,470,000).SIDS: 325 infants; explained SUDI: 72 infants; controls: 1,588 infants.In the univariate analysis, all the clinical features and health markers at birth, after discharge from hospital, during life, and shortly before death, significant among the infants with SIDS were in the same direction among the infants who died of explained SUDI. In the multivariate analysis, at least one apparent life threatening event had been experienced by more of the infants who died than in controls (SIDS: 12% v 3% controls; odds ratio (OR) = 2.55; 95% confidence interval (CI), 1.02 to 6.41; explained SUDI: 15% v 4% controls; OR = 16.81; 95% CI, 2.52 to 112.30). Using a retrospective illness scoring system based on "Baby Check", both index groups showed significant markers of illness in the last 24 hours (SIDS: 22% v 8% controls; OR = 4.17; 95% CI, 1.88 to 9.24; explained SUDI: 49% v 8% controls; OR = 31.20; 95% CI, 6.93 to 140.5).The clinical characteristics of SIDS and explained SUDI are similar. Baby Check might help identify seriously ill babies at risk of sudden death, particularly in high risk infants.