Secular changes in rehospitalization of very low birth weight infants.

Neonatal survival among very low birth weight infants (less than 1,500 g) has improved dramatically during the last decade. Concern about the quality of life among these survivors has focused mainly on the prevalence of severe motor, sensorineural, and intellectual impairment. This study examined the possible effects of increasing survival on less serious morbidity as evidenced by hospital readmission patterns. The experience of VLBW survivors in a geographically defined population has been compared with that of a randomly selected group of heavier infants. As VLBW infant survival rates improved from 35% to 48% between 1968 to 1972 and 1974 to 1978, the rehospitalization rate before 2 years of age increased from 22% to 27%. In contrast, among heavier infants, rehospitalization rates decreased from 9.8% to 8.9%. The relative risk of readmission associated with VLBW thus increased from 2.2 to 3.0. Although this increase in the overall relative risk of rehospitalization in VLBW infants was not statistically significant, there was a dramatic and statistically significant increase in the relative risk of being readmitted because of structural defects (particularly hernias). Overall, there was a marked decline in the number of days spent in the hospital in both birth weight groups.