Examining the Association Between Affordable Care Act Medicaid Expansion and Sexually Transmitted Infection Testing Among U.S. Women

Introduction: Sexually transmitted infection (STI) rates are rising among women in the United States, increasing the importance of routine STI testing. Beginning in 2014, some states expanded Medicaid under the Affordable Care Act, providing health coverage to most individuals in and near poverty. Here, we investigate whether Medicaid expansion changed rates of STI testing among U.S. women. Methods: We analyzed nationally representative 2011-2017 National Survey of Family Growth data from U.S. women ages 15-44. Using difference-in-differences analysis, we assessed whether Medicaid expansion was associated with within-state changes in the prevalence of STI testing in the past 12 months, among women overall and by race/ethnicity and sexual orientation, during each year following Medicaid expansion. Models were adjusted for individual- and state-level demographic and socioeconomic factors. Results: Our sample included 14,196 U.S. women. Medicaid expansion was associated with higher STI testing rates, which increased over time. By 3 years post-expansion, expansion states had increased STI testing by 12.7 percentage points more than nonexpansion states (95% confidence interval [CI] [2.5, 23.0], p = .016). This association was imprecisely estimated within racial/ethnic and sexual orientation subgroups, but trended strongest among white, Latina, and heterosexual women, followed by Black and bisexual women (who tested more often at baseline). Conclusions: Medicaid expansion is associated with increased STI testing among U.S. women; these benefits grew over time but varied by both race/ethnicity and sexual orientation. State governments that fail to expand Medicaid may harm their residents' health by allowing more spread of STIs.