Importance: Observer-rated scales, such as the Finnegan Neonatal Abstinence Scoring Tool (FNAST), are used to quantify the severity of neonatal abstinence syndrome (NAS) and guide pharmacologic therapy. The FNAST, a comprehensive 21-item assessment tool, was developed for research and subsequently integrated into clinical practice; a simpler tool, designed to account for clinically meaningful outcomes, is urgently needed to standardize assessment.
Objectives: To identify FNAST items independently associated with the decision to use pharmacologic therapy and to simplify the FNAST while minimizing loss of information for the treatment decision.
Design, setting, and participants: This multisite cohort study included 424 neonates with opioid exposure who had a gestational age of at least 36 weeks with follow-up from birth to hospital discharge in the derivation cohort and 109 neonates with opioid exposure from the Maternal Opioid Treatment: Human Experimental Research Study in the validation cohort. Neonates in the derivation cohort were included in a medical record review at the Universities of Louisville and Kentucky or in a randomized clinical trial and observational study conducted at Tufts University (2014-2018); the Maternal Opioid Treatment: Human Experimental Research was conducted from 2005 to 2008. Data analysis was conducted from May 2017 to August 2019.
Exposures: Prenatal opioid exposure.
Main outcomes and measures: All FNAST items were dichotomized as present or not present, and logistic regression was used to identify binary items independently associated with pharmacologic treatment. The final model was validated with an independent cohort of neonates with opioid exposure.
Results: Among 424 neonates (gestational age, ≥36 weeks; 217 [51%] female infants), convulsions were not observed, and high-pitched cry and hyperactive Moro reflex had extremely different frequencies across cohorts. Therefore, these 3 FNAST items were removed from further analysis. The 2 tremor items were combined, and 8 of the remaining 17 items were independently associated with pharmacologic treatment, with an area under the curve of 0.86 (95% CI, 0.82-0.89) compared with 0.90 (95% CI, 0.87-0.94) for the 21-item FNAST. External validation of the 8 items resulted in an area under the curve of 0.86 (95% CI, 0.79-0.93). Thresholds of 4 and 5 on the simplified scale yielded the closest agreement with FNAST thresholds of 8 and 12 (weighted κ = 0.55; 95% CI, 0.48-0.61).
Conclusions and relevance: The findings of this study suggest that 8 signs of NAS may be sufficient to assess whether a neonate meets criteria for pharmacologic therapy. A focus on these signs could simplify the FNAST tool and may enhance its clinical utility.