Simplification of the Finnegan Neonatal Abstinence Scoring System: retrospective study of two institutions in the USA

OBJECTIVE: To develop a simplified Finnegan Neonatal Abstinence Scoring System (sFNAS) that will highly correlate with scores ≥8 and ≥12 in infants being assessed with the FNAS. DESIGN, SETTING AND PARTICIPANTS: This is a retrospective analysis involving 367 patients admitted to two level IV neonatal intensive care units with a total of 40 294 observations. Inclusion criteria included neonates with gestational age ≥37 0/7 weeks, who are being assessed for neonatal abstinence syndrome (NAS) using the FNAS. Infants with a gestational age <37 weeks were excluded. METHODS: A linear regression model based on the original FNAS data from one institution was developed to determine optimal values for each item in the sFNAS. A backward elimination approach was used, removing the items that contributed least to the Pearson’s correlation. The sFNAS was then cross-validated with data from a second institution. RESULTS: Pearson’s correlation between the proposed sFNAS and the FNAS was 0.914. The optimal treatment cut-off values for the sFNAS were 6 and 10 to predict FNAS scores ≥8 and ≥12, respectively. The sensitivity and specificity of these cut-off values to detect FNAS scores ≥8 and ≥12 were 0.888 and 0.883 for a cut-off of 6, and 0.637 and 0.992 for a cut-off of 10, respectively. The sFNAS cross-validation resulted in a Pearson’s correlation of 0.908, sensitivity and specificity of 0.860 and 0.873 for a cut-off of 6, and 0.525 and 0.986 for a cut-off of 10, respectively. CONCLUSION: The sFNAS has a high statistical correlation with the FNAS, and it is cross-validated for the assessment of infants with NAS. It has excellent specificity and negative predictive value for identifying infants with FNAS scores ≥8 and ≥12.