Abstract 93: Trends in Intravenous Alteplase Use and Mortality Among Medicare Beneficiaries With Acute Stroke: A Eight-Year Retrospective Analysis

Abstract

Timely stroke treatment with intravenous alteplase (IV-tPA) reduces functional dependence and mortality. Therefore, communities have taken tremendous efforts to increase IV t-PA use through better access to emergency services and stroke centers and through efficient processes at stroke centers. Our objective is to examine the cumulative effect of these processes over an 8-year period on IV-tPA use and mortality in a national sample of Medicare beneficiaries. Methods: Within a sample of Medicare claims from 2007-2014, we identified patients aged 66+ and evaluated the first hospitalization per patient with primary diagnosis of ischemic stroke. Outcome measures were emergency department (ED) -administered IV-tPA and 30-day mortality. We excluded patients without continuous prior 1-year enrollment in Parts A+B and those not treated in the ED. IV-tPA was identified using ICD-9 procedure 99.10 and CPT 37195. Mortality was derived from the Medicare Beneficiary Summary File. We calculated Cochran-Armitage trend tests to assess outcomes over time and chi-square tests to compare outcomes by patient and hospital characteristics. Results: Among 240,486 patients, there was a significant increase in IV-tPA use from 2.8% to 7.7% (p<0.001). IV-tPA utilization was higher in urban areas (5.5% vs. rural 3.7%, p<0.001) and for patients arriving by ambulance (6.7% vs. 2.5%, p<0.001), with the highest IV-tPA rates observed among urban ambulance-transport patients (Figure). Patient demographics were associated with IV-tPA (all p<0.001); younger (age 66-75) and Non-Hispanic White patients were most likely to receive IV-tPA. During the study period, 30-day mortality decreased from 15.7% to 14.5% (p<0.001). Conclusions: Although we observed tripling of IV t-PA during this period, rural areas had lower use when compared with the urban areas. In this ongoing multi-year study, we will investigate enablers and barriers to IV t-PA use within pre-hospital and hospital systems of care.