Medicaid Expansion and Inpatient Hospital Charges Among Women with Major Depressive Disorder

Abstract Objective To evaluate the effect of Medicaid expansion under the Affordable Care Act (ACA) on total inpatient hospital charges among women with MDD, comparing Maryland, an expansion state with an All-Payer Model, and Florida, a non-expansion state. Methods We conducted a retrospective cohort study using the Maryland State Inpatient Database and the Florida State Inpatient Database. The study population included women aged 18–64 years admitted with a primary diagnosis of MDD. The study period was stratified into pre-ACA (2007–2009) and post-ACA (2018–2020) eras. Difference-in-differences models with robust standard errors, complemented by inverse probability-weighted regression adjustment (IPWRA), were employed to estimate policy effects on hospital charges. Models adjusted for age, race/ethnicity, insurance type, discharge quarter, comorbidities, and neighborhood income quartile. Results A total of 122,963 hospitalizations were analyzed. Pre-ACA, baseline charges in Maryland averaged $7,123 (95% CI, 6,878–7,369). Following the ACA, Maryland experienced a moderated increase of $3,108 (95% CI, 2,752–3,465; p<0.001). In contrast, Florida’s charges remained significantly higher, exceeding Maryland by $5,136 pre-ACA and $11,413 post-ACA (p<0.001 for both). Difference-in-differences estimates confirmed that Medicaid expansion in Maryland mitigated cost escalation, producing a net relative reduction of $3,445 (95% CI, −3,886 to −3,004; p<0.001). Stratified analyses demonstrated the greatest financial protection among self-pay and Medicaid patients. Conclusion Medicaid expansion was associated with significantly lower inpatient charges among women with MDD in Maryland compared to non-expansion Florida, and may reduce financial burden, advance equity, and improve hospital resource sustainability.