Importance: Expanding insurance coverage may be associated with overuse of medical care because newly insured patients are insulated from having to pay the full cost.
Objective: To examine the use of ambulance transport before and after the rollout of the Patient Protection and Affordable Care Act (ACA) in New York City (NYC), New York.
Design, setting, and participants: In this case-control study, the volume of ambulance dispatches in NYC for minor injuries before and after the rollout of the ACA was examined. Data were drawn from a census of all ambulance dispatches in NYC between January 1, 2013, and July 31, 2016. Ambulance dispatches for more severe injuries, which are more difficult to characterize as unnecessary, were used as the control group. Analyses were conducted from August 17, 2017, to May, 10, 2019.
Main outcome and measures: The main outcome was the number of ambulance dispatches for minor injuries, defined per month per dispatch zone. The implementation of the ACA was measured using an indicator variable of 1 for dispatches starting January 1, 2014, and 0 for dispatches before January 1, 2014. The number of ambulance dispatches for injuries and major injuries was used to account for secular trends. Injury severity was classified by the dispatchers based on information from the 911 callers with a severity score on a scale of 1 to 8, where 1 is the most severe; minor injuries had a score of 7; injuries, 5; and major injuries, 3.
Results: There were 4 787 180 ambulance dispatches in NYC during the study. After the 2014 expansion of insurance coverage under the ACA, there was an increase in ambulance dispatches for minor injuries compared with dispatches for more severe injuries. Compared with the preimplementation mean (SD) of 20.75 (14.24) minor injury dispatches per dispatch zone per month, there were 7.71 (95% CI, 1.23-14.19) additional minor injury dispatches per dispatch zone per month compared with dispatches for other types of injuries, an increase of 37.2%. Given that NYC has 31 dispatch zones, this increase is equivalent to approximately 239 additional dispatches per month or 2868 additional dispatches per year for minor injuries.
Conclusions and relevance: There was a significant increase in use of ambulance transport for minor injuries in NYC after the ACA insurance expansion, suggesting that the change in health insurance structure was associated with increased use of emergency medical services in nonemergent situations. Future reforms to the US health insurance system should take into account the potential for increased use of emergency medical services in nonemergent situations, which the literature suggests may lead to congestion and slower response times.