Comparison between different mortality risk scores in a neonatal intensive care unit

Abstract

OBJECTIVES: To evaluate and compare birthweight and scores as predictors of neonatal mortality in a Neonatal Intensive Care Unit (NICU). METHODS: The survey included 494 newborns admitted to the neonatal intensive care unit (NICU) of a general hospital in Porto Alegre, southern Brazil, immediately after delivery, between March 1997 and June 1998. Birthweight and scores were evaluated in terms of the variable "death while in NICU". Exclusion criteria were: discharge or death less than 24 hours after admission, admission not immediately following delivery, incomplete study protocol, and congenital malformations incompatible with survival. For CRIB (Clinical Risk Index for Babies) evaluation purposes, only patients born weighing up to 1,500 g were considered. ROC (Receiver Operating Characteristics) curves were calculated for SNAP (Score for Neonatal Acute Physiology) , SNAP-PE (Score for Neonatal Acute Physiology - Perinatal Extension), SNAP II, SNAP-PE II , and CRIB scores, as well as for birthweight. RESULTS: Of the 494 patients studied, 44 died (8.9% mortality). Of the 102 patients born weighing up to 1,500 g, 32 (31.3%) died. The area below the ROC curves ranged from 0.81 to 0.94. There were no statistically significant differences between the areas obtained for all scores evaluated. All mortality risk scores evaluated performed better than birthweight, especially on newborns with birthweight =1,500 g. CONCLUSIONS: All neonatal mortality scores had better performance and were superior to birthweight as measures of in-hospital mortality risk for newborns admitted to NICU.