Increasing Incidence of the Neonatal Abstinence Syndrome in U.S. Neonatal ICUs

ABSTRACTIn recent years, neonatal abstinence syndrome (NAS), which commonly occurs after opioid use in pregnant women, has increased, nearly tripling in the United States between 2000 and 2009. There are limited data on the treatment of infants with NAS or changes in neonatal intensive care units. Previous studies have focused on specific geographic areas or used hospital billing records, not infant-specific clinical information, to identify cohorts. This study aims to analyze changes in incidence as well as treatment of infants with NAS in neonatal intensive care units (NICUs) across the United States from 2004 to 2013.Data were collected from Pediatrix Clinical Data Warehouse, which includes information from NICUs in 33 states and Puerto Rico. Infants were excluded if they had major congenital anomalies, if they were born before 34 weeks, if they were admitted only for suspected cases or to rule out NAS, or if they had exposure to narcotics but were not diagnosed with NAS. Infants were grouped by year of discharge in 1-year periods. Multiple cross-sectional analyses were performed using general linear regression.A total of 10,327 infants from 299 centers met diagnostic criteria for NAS. The frequency of infants with NAS admitted to NICUs increased from 7 cases per 1000 admissions to 27 cases per 1000 admissions between 2004 and 2013 and increased more rapidly between 2009 and 2013 than between 2004 and 2008. The length of hospital stay also increased from 13 to 19 days between 2004 and 2013, and the number of NICU hospital days attributed to NAS increased from 0.6% in 2004 to 4.0% in 2013 (P < 0.001 for trend). The proportion of infants treated for NAS with pharmacotherapy increased from 74% to 87% (P < 0.001 for trend), and the mean duration of therapy increased (P < 0.001 for trend). Whereas the ratio of days of therapy to NICU days increased (P = 0.004 for trend), the proportion of infants discharged while receiving medications decreased (4% in 2004–2005 vs 2% in 2012–2013, P < 0.001 for trend). The most commonly used medication was morphine, and the proportion of infants on morphine increased from 49% in 2004 to 72% in 2013 (P < 0.001 for trend). Between 2004 and 2013, clonidine use increased, and between 2011 and 2013, methadone use decreased.The study found that between 2012 and 2013, many mothers of affected infants used opioid pain relievers rather than illicit drugs, which is consistent with reports suggesting that increased opioid use in pregna