The Economics of Care Regionalization

In 2006 the Institute of Medicine recommended the implementation of regionalized emergency care systems which preferentially route patients to facilities with the ability to best meet their needs.  The concept of regionalization has been readily adopted for stroke, a time critical disease that benefits from organized inpatient care. While 16 states had adopted policies requiring Emergency Medical Services (EMS) providers to transport acute stroke patients to the closest Primary Stroke Center (PSC), bypassing closer non-PSC hospitals, the effects of these policies on clinical and cost outcomes has not been assessed.

Despite being both preventable and treatable, stroke remains one of the leading causes of death in the United States and a leading cause of disability. Stroke is a time critical illness. Therapies for stroke become less effective over time.  Many patients are denied treatment because they arrive at the hospital too late, or they are evaluated at hospitals not prepared to administer acute stroke therapies.

In October 2011 such policy went into effect in the city of Philadelphia, reducing the number of hospitals receiving acute stroke patients, within 6 hours of symptom onset, from 23 to only 13. The policy was implemented by the Philadelphia Fire Department (PFD), the sole advanced-life support EMS transporter in the city, by initiating an EMS destination policy. This policy requires EMS providers to transport acute stroke patients to the closest PSC, potentially bypassing closer hospitals.

The recent EMS destination policy has created a natural experiment, allowing us to examine the time-quality tradeoff for stroke patients in Philadelphia. Our basic strategy would be to study the impact of the policy on clinical and cost outcomes for stroke patients by using a difference-in-difference-in-difference methodology, comparing stroke patients before and after the policy implementation, comparing stroke patients to non-stroke patients (e.g. trauma, myocardial infarction, cardiac arrest, poisoning, sepsis, etc.) who were not affected by the policy, and comparing stroke patients in areas impacted by the policy (i.e. areas where the nearest hospital was deemed non-PSC under the policy) to areas where the closest hospitals was a PSC.

To do so, we have merged prehospital data from PFD EMS encounters with administrative claims data from the largest commercial insurer in the city of Philadelphia. This effort resulted in a unique dataset describing prehospital, acute, and post-acute care across all hospitals in Philadelphia. 

This allows us to determine the impact of the care regionalization policy on clinical and cost outcomes for patients identified by EMS as having had a stroke, balancing between the potential superior care in PSCs versus the fact that transport time increases when the number of care outlets decreases. Similarly, PSCs are often more expensive care facilities, however, timely stroke care can prevent long and expensive rehabilitation process. Our data will put us in a unique position to address this tradeoff given the depth and span of our data.