Epidemiology

Kernicterus rates have remained stable, with no increase in the 1990s

Last Updated: 2011-03-29 13:43:29 -0400 (Reuters Health)

By Dave Levitan

NEW YORK (Reuters Health) - In spite of previous reports to the contrary, there appears to have been no increase during the 1990s in rates of kernicterus -- a rare neurological condition that occurs in some newborns with severe jaundice -- according to a new population-based study.

"Despite a widely held impression in the medical community that kernicterus had disappeared in the 1970s and 1980s, the evidence indicates that it did not," said study lead author Dr. Jordan Brooks, of the University of California, Berkeley, in an e-mail to Reuters Health.

"From the late 1980s through the 1990s," he added, "the incidence of kernicterus in California remained very low, roughly 1 per 200,000 live births, which indicates broad clinical success during this period."

The new study used a different data source than was used in past reports - diagnosis codes from the California Department of Developmental Services - to estimate kernicterus rates. The results were published online ahead of print on March 28 in Pediatrics.

The total study population included 64,346 babies born between 1988 and 1997. The investigators identified a total of 25 "strict definition" kernicterus diagnoses, and another 95 who met a "loose definition." The strict cases were listed with diagnosis codes specific for kernicterus only, while the loosely defined cases included those with a diagnosis for isoimmunization, neonatal jaundice and hemolytic anemias.

The strict cases led to an estimated population incidence of kernicterus of approximately 0.44 per 100,000. The investigators note that there's no indication of any change in incidence over time.

They also compared infant mortalities due to kernicterus between 1979 and 2006. There was a rate of 0.21 deaths per million infants between 1979 and 1992, and a rate of 0.36 per million between 1993 and 2006. The difference wasn't significant.

"It is reassuring that there was no significant difference in kernicterus before and after the 1994 publication of American Academy of Pediatrics guidelines, which suggested a less aggressive approach to management of neonatal hyperbilirubinemia," Dr. Brooks said. "The findings of the current study underscore the necessity of ongoing surveillance and research to determine optimal levels of screening and treatment."

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Pediatrics 2011.