A population-based descriptive study of neonatal abstinence syndrome using hospital discharge and birth certificate data

Abstract

Background: Neonatal abstinence syndrome (NAS), largely a consequence of prenatal opioid exposure, results in substantial morbidity. Population-based studies of NAS going beyond Medicaid populations and hospital discharge data (HDD) alone are limited. Using statewide Tennessee (TN) HDD and birth certificate (BC) data, we examined trends and evaluated maternal and infant factors associated with NAS.

Methods: We conducted a population-based descriptive study during 2013-2017 in TN. NAS infants were identified with International Classification of Diseases (ICD)-9-Clinical Modification (CM) and ICD-10-CM codes in HDD and linked to BC data using iterative deterministic matching algorithms. Descriptive analyses were conducted for infant and maternal factors (exposures) by NAS (outcome). Multivariable logistic regression models were used to estimate adjusted ORs and 95% CIs.

Results: NAS incidence increased from 13.4 to 15.4 per 1,000 live births between 2013-2017 (15% increase; p_trend<0.001), but remained stable in 2017. In adjusted models, maternal factors associated with reduced odds of NAS included breastfeeding (OR:0.55, 95%CI:0.52-0.59) and prenatal care (OR:0.36, 95%CI:0.32-0.41). Smoking, preterm birth and lower birthweight were associated with increased odds of NAS.

Conclusions: This study highlights the value of utilizing surveillance data to monitor trends and correlates of NAS to inform prevention efforts and targeting of public health resources.

Keywords: birth certificates; epidemiology; neonatal abstinence syndrome; newborn; retrospective cohort.

Figure 1.

Study design, exclusions and final analytic sample

Figure 2.

Incidence rate of newborns diagnosed with neonatal abstinence syndrome and potential neonatal abstinence syndrome in Tennessee before and after the ICD-9-CM to ICD-10 CM Transition per 1,000 live births, 2013–2017* *The dotted line indicates when the U.S. transitioned from the ICD-9-CM to ICD-10-CM diagnosis coding system on October 1, 2015.

Figure 3.

Multivariable odds ratios (ORs) and 95% CIs for maternal factors and infant birth outcomes in association with NAS using linked birth and HDD data (n=400,958)* *ORs were adjusted for maternal age at delivery, maternal education, maternal race, prenatal care, infant sex, parity, pre-pregnancy body mass index, and total cigarettes per day during pregnancy as appropriate. Birthweight was also adjusted for length of gestation.