Neonatal Abstinence Syndrome in North Carolina: Incidence and Characteristics among Infants and Mothers

BACKGROUND Neonatal abstinence syndrome (NAS) is a complex disorder characterized by withdrawal symptoms secondary to in utero exposure to drugs capable of producing physical dependence. The objective of this study was to determine the incidence of NAS, as well as infant and maternal characteristics associated with NAS in North Carolina (NC). METHODS This retrospective, cross-sectional, observational study used the State Inpatient Database (SID) to compare the incidence rates of NAS for NC for the year 2016 to historical data (years 2000 to 2013). A multivariable logistic regression model including available covariates of interest was constructed. RESULTS Overall NAS incidence rate (IR) for NC was found to be 9.7 per 1,000 live births, a 32.3-fold increase since 2000 (IR=0.3 in 2000). The multivariable logistic regression model suggested race group (both black [OR 0.11; 95% CI: 0.08, 0.16] and 'other' [OR 0.43; 95% CI: 0.31, 0.61] vs white), ethnicity [OR 0.43; 95% CI: 0.31, 0.61], insurance group (both 'other/self-pay' [OR 0.35; 95% CI: 0.24, 0.52] and 'private insurance' [OR 0.07; 95% CI: 0.05, 0.10] vs Medicaid/Medicare), region (Piedmont [OR 0.62; 95% CI: 0.50, 0.79] vs Mountain), income quartile (both 4th [OR 0.45; 95% CI: 0.26, 0.79] and 3rd [OR 0.70; 95% CI: 0.50, 0.96] vs 1st), county population size (50k-249k [OR 0.54; 95% CI: 0.34, 0.86] vs ≥1 million), birth weight [OR 0.87; 95% CI: 0.78, 0.98], and length of stay [OR 1.23; 95% CI: 1.20, 1.26] as potentially important predictors of NAS. LIMITATIONS Only hospitals providing data to the SID for 2016 were included and ICD-9 codes, in use at the time of data collection, were used. CONCLUSIONS The incidence of NAS has increased in NC in 2016 compared to prior years spanning back to 2000. Specific infant and maternal characteristics including race, ethnicity, payer type, geographic region, county population, parental income status, birth weight, and length appear to be associated with an infant bearing the diagnosis of NAS.