Association of Affordable Care Act Implementation With Ambulance Utilization for Asthma Emergencies in New York City, 2008-2018

This quasi-experimental cohort study assesses the association between Affordable Care Act implementation and asthma treatment by examining changes in ambulance dispatch rates for asthma emergencies in New York City between 2008 and 2018. Importance Emergency medical services (EMS) are an essential component of the health care system, but the effect of insurance expansion on EMS call volume remains unclear. Objective This study investigated the association between health insurance expansion and EMS dispatches for asthma, an ambulatory care-sensitive condition. We hypothesized that insurance expansion under the Patient Protection and Affordable Care Act (ACA) would be associated with decreased EMS dispatches for asthma emergencies. Design, Setting, and Participants This cohort study examined 14865267 ambulance calls dispatched within New York City from 2008 to 2018, including 217303 calls for asthma-related emergencies, and used interrupted time series analysis to study the change in the annual incidence of EMS dispatches for asthma emergencies after implementation of the ACA. Multivariable linear regression examined the association between the uninsured rate and the incidence of asthma-related dispatches, controlling for population demographic characteristics and air quality index. Exposures Implementation of ACA on January 1, 2014. Main Outcomes and Measures Incidence of EMS dispatches for asthma emergencies per 100000 population per year (ie, asthma EMS dispatch rate) as classified by the 911 call-taker. Results In this study of 217303 EMS dispatches for asthma-related emergencies, there was a decrease in the asthma EMS dispatch rate after implementation of the ACA, from a mean (SD) of 261 (24) dispatches per 100000 population per year preintervention to 211 (47) postintervention (P = .047). This decrease in asthma EMS dispatch rate after ACA implementation was significant on interrupted time series analysis. Prior to 2014, the annual asthma EMS dispatch rate was increasing by 11.8 calls per 100000 population per year (95% CI, 6.1 to 17.4). After ACA implementation, the asthma EMS dispatch rate decreased annually by 28.5 calls per 100000 population per year (95% CI, -37.6 to -19.3), a significant change in slope from the preintervention period (P < .001). Multivariable linear regression, controlling for percentage of individuals younger than age 18 years, degree of racial/ethnic diversity, median household income, and air quality index, found that a 1% decrease in the citywide uninsured rate was associated with a decrease of 98.9 asthma dispatches per 100000 population per year (95% CI, 5.72-192.10; P = .04). Conclusions and Relevance Insurance expansion within New York City under the ACA was associated with a significant reduction in the asthma EMS dispatch rate. Insurance expansion may be a viable method to reduce EMS utilization for ambulatory care-sensitive conditions such as asthma. Question What is the association between insurance expansion and emergency medical services (EMS) dispatches for an ambulatory care-sensitive condition like asthma? Findings In this cohort study including 217303 EMS dispatches for asthma emergencies in New York City, implementation of the Patient Protection and Affordable Care Act was associated with a decrease in calls for asthma emergencies. In adjusted models, larger decreases in the uninsured rate were associated with larger decreases in the asthma EMS dispatch rate. Meaning The findings of this study suggest that insurance expansion may lead to improved outpatient management of ambulatory care-sensitive conditions like asthma, resulting in decreased utilization of EMS.