Interinstitutional variation in prediction of death by SNAP-II and SNAPPE-II among extremely preterm infants.

BACKGROUND

Illness severity scores predict death among infants admitted to NICUs. We know of no study limited to a population defined by an extremely low gestational age.

METHODS

A total of 1467 infants born before the 28th postmenstrual week at 14 institutions were given Score for Neonatal Acute Physiology II (SNAP-II) and Score for Neonatal Acute Physiology Perinatal Extension II (SNAPPE-II) values based on data collected within the first 12 postnatal hours. All deaths in the intensive care nursery were identified.

RESULTS

The rate of death before postnatal day 28 was 13% (interinstitutional range: 7%-20%), whereas the overall mortality rate was 18% (8%-31%). SNAP-II values, SNAPPE-II values, and mortality rates tended to decrease with increasing gestational age. Even within gestational age strata, however, the risk of death decreased with decreasing SNAP-II and SNAPPE-II values. The positive predictive values of most SNAP-II and SNAPPE-II cutoff levels were close to 30%. In general, institutions' mortality rates increased with the proportions of infants whose SNAP-II values were >/=30.

CONCLUSION

The physiologic instability in the first 12 postnatal hours that is identified by illness severity scores conveys information about the risk of death among infants at the lowest gestational ages.