Neonatal Outcomes in a Medicaid Population With Opioid Dependence

Abstract

Confounding may account for the apparent improved infant outcomes after prenatal exposure to buprenorphine versus methadone. We used Massachusetts Medicaid Analytic eXtract (MAX) data to identify a cohort of opioid dependent mother-infant pairs (2006–2011) supplemented with confounder data from an external Boston cohort (2015–2016). Associations between prenatal buprenorphine versus methadone exposure and infant outcomes in the MAX Cohort were adjusted for measured MAX confounders, and unmeasured confounders with bias analysis using External Cohort data. 477 women in MAX were treated with methadone and 543 with buprenorphine. More buprenorphine users were white and used psychotropic medications. Adjusting for MAX confounders, risk ratios in buprenorphine versus methadone exposed infants were: preterm birth (0.45, 95% CI: 0.34, 0.61) and low birth weight for gestational age (0.75, 95% CI: 0.51, 1.11). The mean difference in infant hospitalization was −7.35 days (95% CI: −9.16, −5.55). After further adjustment with bias analysis estimates were: preterm birth (0.53, 95% CI: 0.39, 0.71), low birth weight for gestational age (1.14, 95% CI: 0.77, 1.69), and hospitalization (−3.66 days, 95% CI: −5.46, −1.87). External confounder data can be used to adjust for unmeasured confounding in studies of prenatal outcomes in women on opioid agonist therapy based on administrative databases.