Publication Date

2019-06-18

Availability

Embargoed

Embargo Period

2021-06-17

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Epidemiology (Medicine)

Date of Defense

2019-04-29

First Committee Member

Tatjana Rundek

Second Committee Member

WayWay M. Hlaing

Third Committee Member

Tulay Koru-Sengul

Fourth Committee Member

Ralph L. Sacco

Abstract

Racial/ethnic minorities and women are disproportionately affected by stroke. Non-Hispanic (NH) Blacks and Hispanics have a greater risk of stroke compared to NH Whites. Similarly, women have a greater lifetime risk of stroke and experience more strokes annually compared to men. The vast majority of these strokes are ischemic and are typically characterized by a clot obstructing blood flow to the brain. Previous studies have shown that race/ethnic minorities and women who are hospitalized with ischemic stroke are less likely to receive many evidence-based care processes and treatment defined by the American Heart Association/American Stroke Association (AHA/ASA). NH Blacks and women receive intravenous tissue plasminogen activator (tPA), the standard thrombolytic therapy for acute ischemic stroke, less frequently than NH Whites and men. Furthermore, NH Blacks and women experience greater disability and overall lower quality of life in the months and years following an ischemic stroke. This dissertation sought to further assess racial/ethnic and sex disparities in the acute phase of stroke, with a primary focus on time to treatment with tPA (door-to-needle time), admission blood pressure, and clinical outcomes in patients hospitalized with ischemic stroke. Specifically, this dissertation sought to a) determine whether there are racial/ethnic and/or sex disparities among tPA-treated acute ischemic stroke patients in achievement of the AHA/ASA target door-to-needle time <60 minutes and the Target: Stroke Phase II goal door-to-needle time><45 >minutes; b) determine whether there are racial/ethnic and/or sex differences in severely uncontrolled hypertension at admission (SBP > 185 mmHg and/or DBP > 110 mmHg) – a contraindication to tPA which must be treated before tPA can be administered – among patients hospitalized with ischemic stroke; and c) determine whether there are racial/ethnic and/or sex disparities in the following 3 clinical outcomes for patients hospitalized with ischemic stroke: in-hospital death, independent ambulation at discharge (IAD), and favorable modified Rankin Score (mRS) at discharge. Each aim for this dissertation was completed using data from the Florida-Puerto Rico Collaboration to Reduce Stroke Disparities (CReSD) Study. The CReSD Study consists of data from patients admitted to participating hospitals in Florida and Puerto Rico. Data are included for patients admitted or discharged with final clinical diagnosis of ischemic stroke, hemorrhagic stroke, transient ischemic attack (TIA), or stroke not otherwise specified. From 2010 through 2017, there were 132,644 ischemic stroke records entered into the CReSD Registry from 98 hospitals (85 in Florida, 13 in Puerto Rico). Among records with final clinical diagnosis of ischemic stroke, 50% are women. Sixty-three (63%) are NH White, 18% are NH Black, 13% are Hispanics residing in Florida, and 5.0% Hispanics residing in Puerto Rico. The mean age + standard deviation in years is 71+14 and 32% are working-age (18 to 65 years of age). Hypertension is the most common comorbidity (68%), followed by dyslipidemia (39%) and diabetes mellitus (30%). Twenty-two (22%) percent have a history of coronary artery disease or prior myocardial infarction and 26% have a history of stroke or TIA. Multivariable logistic regression modeling was performed to test the hypotheses of each aim. The regression models were fit using generalized estimating equations, GEE, to account for the clustering effect at the hospital level. After adjustment for multiple patient and hospital factors including stroke onset-to-hospital arrival time, stroke severity, academic status of hospital, and hospital size, women were less likely to be treated with tPA within 60 minutes and 45 minutes of hospital arrival compared to men. Likelihood of severely elevated admission blood pressure was greater in NH Blacks and women compared to NH Whites and men, respectively. NH Blacks had lower odds of in-hospital death, independent ambulation at discharge, and favorable modified Rankin score at discharge compared to NH Whites. Similarly, women had lower odds of in-hospital death, independent ambulation at discharge, and favorable modified Rankin score compared to men. Significant racial/ethnic and sex disparities were found among hospitalized ischemic stroke patients in CReSD. These findings highlight the need to improve blood pressure management and increase pre-hospital interventions to control blood pressure in incoming stroke patients, particularly in NH Blacks and women. It is also crucial to identify additional patient and process-of-care factors that contribute to slower treatment times in women and greater disability at discharge in NH Blacks and women.

Keywords

race; ethnicity; sex; disparities; stroke; outcomes

Available for download on Thursday, June 17, 2021

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