Association of a Simplified Finnegan Neonatal Abstinence Scoring Tool With the Need for Pharmacologic Treatment for Neonatal Abstinence Syndrome

Key Points Question Can a simplified Finnegan Neonatal Abstinence Scoring Tool (FNAST), composed only of dichotomized items that are independently associated with the decision to initiate pharmacologic therapy, discriminate between infants who did and did not receive therapy as effectively as the original FNAST? Findings In this cohort study of 424 neonates with opioid exposure, the simplified FNAST discriminated between neonates who did and did not receive pharmacologic treatment nearly as well as the original FNAST. Meaning Use of a simplified FNAST may provide an accurate means of identifying neonatal abstinence syndrome and may enhance the clinical utility of the tool.

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.

+ Invited Commentary + Supplemental content Introduction
The medical and nonmedical use of opioids in the United States has increased significantly during the last decade. [1][2][3][4] Opioid use disorder (OUD) during pregnancy increased from 1.5 per 1000 live births to 6.5 per 1000 live births between 1999 and 2014. 5 Antenatal exposure to opioids has led to a 5-fold rise in the incidence of neonatal abstinence syndrome (NAS) between 2004 and 2014, a number that continues to increase. 6,7 Neonatal abstinence syndrome is a withdrawal syndrome that occurs after the interruption of the passive transfer of maternal opioids at the time of birth. The diagnosis of NAS is dependent on the presence of key signs of withdrawal, with severity being highly variable. 8,9 Every neonate exposed to opioids in utero is somewhere along the continuum of withdrawal. While some neonates have mild signs and normal physiologic functions, others have more severe NAS that requires pharmacologic treatment to avoid major complications. 10 Differences in the expression of NAS is associated with many factors, including the type(s) of opioid exposure, coexposure with other illicit drugs and/or psychotropic medications, genetic and epigenetic variability, the gestational age and sex of the neonate, breastfeeding, and parental engagement. [11][12][13][14][15][16][17] Observer-rated scales have been used for more than 40 years to assess the severity of NAS and guide the initiation and adjustment of pharmacologic therapy. [18][19][20][21] Differences between raters in the assessment of NAS have been associated with significant differences in initiation and duration of pharmacologic therapy, length of hospital stay, and health care utilization. 22 The Finnegan Neonatal Abstinence Scoring Tool (FNAST) is commonly used for the assessment of neonates with NAS. [23][24][25] It is a screening tool that comprises 21 items, with many items having 2 to 4 subcategories and weighting for each category, which varies from 1 to 5. 18,19 Although differences among raters have been observed with the use of the FNAST, 26,27 these rater differences can be minimized with a comprehensive educational approach that optimizes and then maintains interobserver reliability. 22,[26][27][28][29] Several tools have been developed to shorten and simplify the FNAST, 27,30-33 but existing studies are limited by small cohorts that lack generalizability, study samples that do not differentiate between neonates with and without pharmacologic treatment, and a lack of external validation of the findings.
The goal of this study was to significantly shorten and simplify the original FNAST by focusing on signs of withdrawal that prompt clinical intervention. In this article, we address the following questions. First, is information lost by dichotomizing components of the FNAST and eliminating weighting? Second, are there large differences among cohorts in how frequently specific signs are observed? Third, which binary-coded FNAST items are independently associated with the receipt of pharmacologic therapy?

Methods
Retrospective medical record reviews of consecutive neonates with antenatal opioid exposure were conducted at the University of Louisville and University of Kentucky for infants born in 2014. In addition, prospective data were obtained from an 8-site clinical trial that compared methadone with morphine for the treatment of NAS (conducted 2014-2018, led by Tufts University) 34 and from a concurrent observational study of neonates whose parents gave consent for the clinical trial but did not require treatment or whose parents refused consent for randomization in the clinical trial but The present analysis used a single assessment point for each neonate, ie, the time of the highest score on the day the neonate initially received pharmacologic therapy for NAS or on day 3 of life if never treated. The third day was selected for analyzing untreated neonates because it was the median day when treatment was initiated among neonates who were treated. The criteria for initial treatment for NAS varied by site and included: 3 consecutive scores of at least 8 or 2 consecutive scores of at least 12 on the FNAST at the Kentucky sites; 2 consecutive scores of at least 8 or 1 score of at least 12 on the FNAST for the multisite study; and 2 consecutive scores of at least 9 or 1 score of at least 13 on the NAS scale for the MOTHER study.

JAMA Network Open | Pediatrics
Items on the FNAST with multiple categories were dichotomized as present or absent; if any sign was recorded, the neonate was coded as having the sign (eg, hyperactive Moro reflex and markedly hyperactive Moro reflex were both coded as hyperactive Moro reflex). The 2 items related to tremors were combined to form a single binary item.

Statistical Analysis
Differences among the 3 cohorts in the frequency of each binary item were tested using a χ 2 test for proportions. Endorsement of each item across cohorts was also compared using the area under the curve (AUC). Items that differed by more than 50 percentage points among cohorts and items that were never observed were excluded from subsequent analyses. Forward stepwise multivariable logistic regression was used to determine which of the remaining items were independently associated with receipt of pharmacologic therapy, adjusting for cohort. The criteria for stepping items into the model and retaining items in the model were P < .10 and P < .05, respectively. Model discrimination was evaluated using the AUC. The selected items were validated by calculating the AUC of a multivariable logistic regression on the validation data set. Thresholds for the new score were selected to optimize agreement between it and the FNAST in categorizing scores into 3 groups: low (<8 on FNAST), medium (Ն8 to <12), and high (Ն12).
Statistical analysis was conducted with SAS statistical software version 9.4 (SAS Institute).
Except as stated for model building, statistical significance was set at P < .05, and all tests were 2-tailed.  Table 4. For example, the 3 levels of sleeps after feeding were collapsed into 1 category; similarly, the 2 categories of fever were collapsed into 1. Thresholds of 4 and 5 on the simplified scale yielded the closest agreement with FNAST thresholds of 8 and 12, with a weighted κ of 0.55 (95% CI, 0.48-0.61) ( Table 5).

Discussion
In this cohort study, a simplified, binary, 8-item FNAST scale was developed to discriminate between neonates who did and did not receive pharmacologic therapy based on traditional FNAST parameters ( consecutive FNAST scores of Ն8 or 1 of Ն12; 3 consecutive scores Ն8 or 2 of Ն12), and they did not lose predictive power in an independent validation sample that used a different algorithm (ie, the MNS) for assessing the need for pharmacologic therapy. The high AUC that we observed in the validation cohort is evidence of the transportability of the 8-item simplified scale, especially since the MNS scale differed from the FNAST by including some signs that were not in the FNAST and excluding others that were.
When the FNAST and simplified FNAST scores were categorized according to treatment cutoffs, the agreement was only moderate (weighted κ = 0.55; 95% CI, 0.48-0.61). There are 2 cutoffs for the original FNAST that were predetermined at 8 and 12 points, leaving little room to set the simplified FNAST thresholds to optimize agreement. In practice, the treatment decision is based on frequent assessments, not a single score. Because there is no criterion standard, there is currently no method for determining whether an algorithm based on the original FNAST or the 8-item version would yield better clinical outcomes.
The model did not select some signs because they occurred infrequently or almost always and hence were not useful in predicting pharmacologic treatment for NAS. Not every item that was associated with the outcome in univariate analyses made it into the final logistic regression model.
Having a high odds ratio in a univariate analysis does not ensure retention in a multivariable model if an item is associated with other items and/or the confidence interval is wide. Signs that were absent from the final model may still be clinically important, although they do not have to be checked to make a treatment decision.
Each item on the original FNAST was weighted and based on clinical observations at the time the tool was developed. Discerning the degree of expression of several items on the original FNAST has proven difficult. 35 Differences in the assessment of withdrawal severity have been associated with suboptimal short-term outcomes in neonates with NAS. 36 In this study, we evaluated differences in the scoring of individual items of the FNAST among different cohorts (Table 3) and    Our proposed scale overlaps with the Eat, Sleep, and Console (ESC) assessment method. [37][38][39] This method assesses if a neonate with opioid exposure can eat at least 1 ounce (or age appropriate volume) per feed or breastfeed well, sleep at least 1 hour, and be consoled within 10 minutes. While the ESC approach has gained acceptance at many sites in the United States since the initial quality improvement study introduced the approach in 2017, the generalizability and safety of the approach has yet to be demonstrated. Tachypnea, which is a key sign of central nervous system irritability and autonomic dysfunction, is not assessed with the ESC approach. However, it was retained in our simplified FNAST, in the sFNAST, and in the 5-item MNS.

Limitations
There are several limitations in this study. First, data were retrospective for some of the cohorts and prospective for others. Next, most binary FNAST items had statistically significant differences among cohorts. The 2 items that were eliminated because of pronounced sample differences in percentage endorsement (ie, high-pitched crying and hyperactive Moro reflex) could perhaps be reintegrated in the future, if consistency in assessment can be achieved. Despite the statistically significant variability of some of the included items, the simplified score's ability to discriminate neonates who were treated vs those who were untreated (as measured by the AUC) was very high, even in the validation cohort.
Shorter tools have been published (ie, the 5-item MNS and the ESC), but we retained 8 items because of the trade-off between brevity and potential loss of generalizability. Further prospective studies that incorporate nursing and caregiver input are needed to establish clinical utility and determine the validity and reliability of this simplified tool in comparison with other tools and approaches.

Conclusions
In this study, the 21-item FNAST was simplified to an 8-item scale that discriminated nearly as well as the original and was validated with an independent cohort. This shorter assessment tool could simplify clinical assessment by focusing on components that are relatively consistent across sites. It is important to prospectively validate this scale, which could be widely used and lead to the standardization of the clinical approach and management of neonates prenatally exposed to opioids.