Medicaid Expansion and Health Care Use Among Adults With Asthma and Low Incomes: The Adult Asthma Call-Back Survey

Asthma disproportionately affects Black people and people with low incomes, but Medicaid expansion (hereinafter, expansion) data on these populations are limited. We investigated health care use among adults with asthma, before and after expansion, and examined whether asthma-related health care use after expansion varied by demographic characteristics.

We analyzed data from the 2011-2013 and 2015-2019 Behavioral Risk Factor Surveillance System Adult Asthma Call-Back Survey on participants aged 18-64 years with current asthma and low incomes in 23 US states. We assessed 5 asthma-related outcomes, including medical visits (routine and emergency) and medication use, for expansion and nonexpansion groups. We used t tests to compare weighted percentages and 95% CIs, then performed adjusted difference-in-differences analyses. Secondary analyses stratified data by race, ethnicity, and sex.

Primary analyses (N = 10 796) found no significant associations between expansion and any outcome. Analyses stratified by race and ethnicity found no significant changes (eg, asthma controller medication use among non-Hispanic Black participants in the expansion group was 24.1% [95% CI, 14.4%-37.5%] in 2011-2013 and 35.5% [95% CI, 27.0%-45.1%] in 2015-2019; P = .13). Use of asthma controller medication increased significantly among non-Hispanic Other participants in the nonexpansion group (2011-2013: 16.0% [95% CI, 9.5%-25.5%]; 2015-2019: 40.2% [95% CI, 25.5%-56.8%]; P = .01). Asthma-related hospitalizations decreased significantly among women in the expansion group: 2011-2013 (7.8%; 95% CI, 5.3%-11.3%) and 2015-2019 (3.5%; 95% CI, 2.5%-4.9%) (P = .009).

Investigating factors other than health insurance (eg, social determinants of health) that influence the use of asthma-related health care could advance knowledge of potential strategies to advance health equity for adults with asthma and lower incomes.