CHANGES IN SURVIVAL PATTERNS OF VERY-LOW-BIRTH-WEIGHT INFANTS FROM 1980 TO 1993

Objective: To determine changes in survival patterns among very low-bi rth-weight (<1500 g) infants between 1980 and 1993. Methods: The recor ds of 12 960 infants treated in nine perinatal intensive care centers in Florida were analyzed on the basis of survival (discharged alive fr om hospital) according to four independent variables: birth weight, ra ce, sex, and transport status. Survival curves were generated using lo g linear regression techniques for each race by sex by transport statu s group. Results: Race, sex, and transport status correlated significa ntly with survival: survival percentages were higher among black infan ts, female infants, and infants transported to the perinatal intensive care centers than among white infants, male infants, and those admitt ed initially to the tertiary care centers. After 1985, 95% of neonates with birth weights between 1200 and 1500 g survived. In addition, sur vival of 500- to 550-g transported black male infants increased from z ero to near 80% during the 13-year period; that of 500- to 550-g inbor n white female infants rose from 35% to 70%. Conclusions: These result s illustrate the value of taking into account race, sex, and transport status in efforts to understand the contribution that neonatal intens ive care of extremely low-birth-weight infants makes to the lowering o f infant mortality, and of using multivariable statistical procedures to generate predicted survival probabilities for different subpopulati ons. These probabilities can be applied to (1) predicting survival for specific subgroups of extremely low-birth-weight infants, and (2) hel ping physicians develop clinical guidelines for extending care to infa nts at the threshold of viability.