Trends in Infant Mortality Among Infants Admitted to Four NICUs in North Carolina † 1212

Abstract

OBJECTIVE: This study examined race specific trends in the mortality of very-low-birth-weight (VLBW) infants over two time periods among newborns admitted to four neonatal intensive care units (NICUs) in North Carolina. METHODS: Data for this study were obtained from the NC-NICU statewide database from 1988-1995. Eleven hospitals in North Carolina contribute clinical data on all admissions to their NICUs to a central computerized database. Four tertiary level NICUs which have contributed data consistently to this database were selected for study based on the similar number of admissions per year and the similar services available at each medical center. Data for all 2,535 VLBW infants (500-1500 grams) admitted to the four centers were merged and mortality rates for the two time periods were compared. The time periods selected for analysis were Pre-Surfactant, the period before each NICU began using surfactant, and Post-Surfactant, the period following the introduction of surfactant use at each of the four NICUs. Multiple logistic regression was used to determine the effect of surfactant therapy and race on mortality while controlling for infants' sex, birth weight and NICU. RESULTS: Since the introduction of surfactant therapy, the mortality rate has decreased by 33 percent for VLBW infants of both races in our study population. The reduction was similar for white (-34.2%) and black (-26.2%) infants. Multiple logistic regression found that VLBW infants of both races were significantly less likely to die in the post-surfactant than the pre-surfactant time period controlling for sex, race, birth weight and NICU (odds ratio = 0.54, 95% CI= 0.40, 0.73). The findings were similar when separate models were run for white infants (odds ratio = 0.56, 95% CI= 0.38, 0.81) and black infants (odds ratio= 0.50, 95% CI= 0.31, 0.82). CONCLUSION: Since the introduction of surfactant therapy in four North Carolina NICUs, mortality rates for black as well as white VLBW infants have decreased significantly. This differs from the conclusion of Hamvas et al. (N Eng J Med 1996;334:1635-40), who found that the mortality rate for black infants did not change significantly in the post-surfactant era.