Abstract TMP35: Prehospital Bypass Policies Increase The Proportion Of Stroke Patients Transported To Primary Stroke Centers - A Quasi-experimental Study In A National Sample Of Medicare Beneficiaries

Objective: Prehospital bypass policies were designed to encourage transport of eligible stroke patients to stroke centers in order to receive rapid assessment and treatment. In a national dataset we examined the relationship between implementation of bypass policies and the proportion of patients transported to stroke centers. Methods: We included EMS transported ischemic stroke patients aged 66+ from a 20% sample of Medicare claims (2007 - 2014). We excluded patients not admitted through the ED, and those not continuously enrolled in parts A/B in the prior year. The outcome measure was transport to PSC. Stroke certification status was validated by multiple stroke certification databases; policy implementation details were obtained from review of statutes and regulations. We employed difference-in-differences (DID) analyses with a state-level random intercept. Results: A total of 20,345 patients were included in the study with 7,239 from policy states and counties and 13,106 from non-policy states and counties. The proportion of patients arriving at PSCs increased from 28% to 43% in non-policy areas and 33% to 57% in policy areas. The DID analysis revealed a net effect of 11% (p Discussion: In pre-thrombectomy era, statewide prehospital bypass policies were related to significant increases in proportion of stroke patients transported to stroke centers. Future analyses will assess if these effects occur in the thrombectomy era, and if these policies influence delivery of stroke treatments.