ACA dependent coverage extension and young adults' substance-associated ED visits.

Objectives: The Affordable Care Act (ACA), enacted in 2010, aimed to improve health insurance coverage and access to care, notably through a provision extending dependent coverage up to age 26 years. This study investigates the ACA's impact on substance use disorder (SUD)-associated emergency department (ED) visits among young adults aged 23 to 29 years.

Study design: A quasi-experimental study analyzed opioid- and alcohol-associated ED visits and inpatient admissions among young adults (aged 23-25 [treatment] vs 27-29 [comparison] years) using 2007-2019 Nationwide Emergency Department Sample data.

Methods: A difference-in-differences approach assessed the ACA's impact, adjusting for covariates including sex, comorbidities, payer source, income, residence, and hospital region. Generalized linear models estimated adjusted ORs with 95% CIs, ensuring robust analysis of the ACA's effects on substance-related health care utilization.

Results: Opioid-associated ED visits had no change between the treatment and comparison groups, whereas alcohol- associated ED visits declined more for the treatment group after the ACA (OR, 0.841; 95% CI, 0.828-0.855). No changes in inpatient admissions among opioid- or alcohol-associated visits, respectively, were seen between the 2 groups.

Conclusions: Our findings indicate that the ACA's implementation led to mixed effects on substance-associated health care utilization among young adults, with reduced alcohol-associated visits in the treatment group but unchanged discrepancies in opioid-associated ED visits and inpatient admissions between the 2 groups. Further research is warranted to explore state-level variations and population-level substance use trends along with continuous monitoring to inform interventions addressing substance-associated public health challenges.