Mortality Risk Assessment by SNAP-II and SNAPPE-II among Very Low Birth Weight Newborns- An Observational Study

Abstract

Introduction: Very Low Birth Weight (VLBW) babies are those with a birth weight of less than 1500 gm and require special care, attention, and resources. However, despite all efforts, their mortality rate remains high. Proper assessment of these neonates is crucial to identify high-risk cases and take early steps to reduce mortality. In addition to technical advances in neonatal care, severity scores have been developed to predict neonatal mortality. Richardson developed the Score for Neonatal Acute Physiology (SNAP-II) and SNAP with Perinatal Extension (SNAPPE-II) as scoring systems for predicting mortality in the Neonatal Intensive Care Unit (NICU). Aim: To assess the usefulness of SNAP-II and SNAPPE-II as predictors of mortality in VLBW neonates. Materials and Methods: This was an observational cross-sectional study involving 145 VLBW neonates admitted to the NICU of North Bengal Medical College and Hospital (NBMCH) from May 2019 to April 2020. Relevant data were collected to assess the mortality risk scores SNAP-II and SNAPPE-II. The outcome of discharge or death was recorded. Data entry was performed using MS excel and analysed using Statistical Package for Social Sciences (SPSS) version 20.0. The relationship between newborn survival and SNAP-II or SNAPPE-II final scores was determined using the Mann- Whitney U test, and the relationship between survival and various SNAP-II and SNAPPE-II score categories was determined using Fisher’s-Exact Test. A p-value of less than 0.05 was considered statistically significant. An ROC curve was generated to determine the best cutoff score for predicting mortality. Results: The mean scores of SNAP-II and SNAPPE-II were higher in babies who expired compared to those who survived. The mean (±SD) SNAP-II scores were 8.96 (±13.865) for survived newborns and 41.08 (±23.174) for expired newborns. The mean (±SD) SNAPPE-II scores were 20.01 (±14.54) for survived newborns and 48.85 (±25.02) for expired newborns. The optimal cutoff values for SNAP-II and SNAPPE-II in predicting mortality were 31.5 and 36, respectively. The sensitivity and specificity of SNAP-II were 83.0% and 89.1%, while for SNAPPE-II they were 69.8% and 89.1%, respectively. Conclusion: The mean SNAP-II and SNAPPE-II scores were higher among expired VLBW neonates compared to those who survived. A SNAP-II score of 31.5 and SNAPPE-II score of 36 were associated with higher mortality, indicating that both scores are effective predictors of mortality regardless of Gestational Ages (GA) and birth weight.