Association of race and in‐hospital outcomes following acute pulmonary embolism: A retrospective cohort study

Abstract Background Racial disparities in health care are well established, with Black patients frequently experiencing the most significant consequences of this inequality. Acute pulmonary embolism (PE) is increasing in incidence and an important cause of morbidity and mortality in the United States, but little is known about racial disparities in the inpatient setting. Hypothesis Black and White patients admitted with acute PE will have different in‐hospital outcomes. Methods All PE patients from January 1, 2016 to June 30, 2017 were retrospectively identified using ICD‐10 codes. Data were abstracted by manual chart review for all image‐confirmed PEs. Results A total of 782 patients with acute PE were identified, of which 319 (40.8%) were Black and 463 (59.2%) were White. Black patients had higher BMI (median [Q1–Q3]: 30.3 [25.4–36.6] vs. 29.3 [24.5–33.8] kg/m2, p = .017), were younger (61 [48–74] vs. 67 [54–75] years, p = .001), and were more likely to have a history of heart failure (16.0 vs. 7.1%, p < .001), while White patients had higher rates of malignancy (46.9 vs. 34.5%, p = .001) and recent surgery (29.6 vs. 18.2%, p < .001). Black patients were more likely to receive systemic thrombolysis (3.1% vs. 1.1%, p = .040), while White patients had numerically higher rates of surgical embolectomy (0.3% vs. 1.1%, p = .41). No difference in inpatient mortality was observed; however, Black patients had longer hospital length of stay (5.0 [3–9] vs. 4.0 [2–9] days, p = .007) and were more likely to receive warfarin (23.5 vs. 12.1%, p < .001). Conclusions Similar in‐hospital mortality rates were observed in Black and White patients following acute PE. However, Black patients had longer hospital stays, higher warfarin prescription, and fewer traditional PE‐related risk factors.


| INTRODUCTION
Racial disparities are well documented in health care. Within cardiovascular disease, Black Americans have higher rates of morbidity and mortality following diagnosis of coronary artery disease, atrial fibrillation, aortic stenosis, and sudden cardiac death, but are less likely to receive guideline-directed medications and procedures. [1][2][3][4][5][6][7] These disparities are especially important in the care of venous thromboembolism (VTE), specifically acute pulmonary embolism (PE).
This common condition affects nearly 1 million Americans annually and is the third leading cause of cardiovascular mortality. [8][9][10] Black patients are nearly twice as likely to be hospitalized for acute PE and suffer 50% higher rates of 30-day mortality. [11][12][13] Black patients are also more likely to experience complications from treatment, including bleeding and inadequate anticoagulation, when compared to other races. [14][15][16] Health disparities and outcomes following index hospitalization for acute PE remain under investigation. In this study, we aimed to: (1) describe the characteristics of Black and White patients hospitalized for management of acute PE, (2) assess differences by race in performance of risk-stratifying diagnostic tests and referral for advanced therapies, and (3) describe the association between race and outcomes, including all-cause in-hospital mortality, discharge to hospice, and both intensive care unit (ICU) and hospital length of stay.

| METHODS
Methods are described in detail in a previously publication by Holder et al. 17

| Patient identification
Our large health system is comprised of approximately 1500 inpatient beds across one academic hospital and two community hospitals. ICD-10 codes for PE were utilized to identify an initial cohort of patients who presented from January 1, 2016 to June 30, 2017. An electronic health record (EHR) database was queried for demographic, treatment, and outcome information during initial hospitalization. This study was IRB exempt and no informed consent was required.

| Inclusion/exclusion criteria
Inclusion and exclusion criteria are described in the prior study. 17 Patients ≥18 years of age with imaging-confirmed acute PE who identified as Black or non-Hispanic White were included. Patients with any other thromboembolic event including, but not limited to, fat embolism, air embolism, septic embolism, chronic thromboembolic pulmonary hypertension were excluded. Patients without imaging confirmed PE were also excluded.

| Outcomes
The primary outcome was the association between race and the composite endpoint of all-cause mortality during index hospitalization for PE and discharge to hospice. Other outcomes of interest included the association between race and hospital utilization defined as ICU admission, ICU LOS, and hospital LOS.

| Statistical analysis
Continuous data are presented using the median with 25th and 75th percentiles (Q1-Q3), while categorical data are shown using counts

| Diagnostic testing and risk categories
Imaging and laboratory findings are shown in Table 2. Cardiac biomarkers (troponin and BNP) and radiographic images were ordered with similar frequency with no difference in the frequency of abnormal results between groups. Black patients were more likely to have right ventricle (RV) hypokinesis (45.3 vs. 34.8%, p = .016) and elevated right ventricular systolic pressure (RVSP) ( Table 2). There was no significant difference in risk stratification, as defined by the 2019 European Society of Cardiology (ESC) guidelines for acute PE, between Black and White patients (Table S1).

| Advanced therapies
The use of advanced therapies is depicted in Table 3. Black patients with acute PE received systemic tissue plasminogen activator (tPA) more frequently than White patients with acute PE (3.1% vs. 1.1%, p = .040) ( Table 3). There was no difference in the use of catheterdirected thrombolysis (CDT) or extracorporeal membrane oxygenation (ECMO) between groups (Table 3).

| Hospital utilization and mortality
Hospital utilization, intensive care unit (ICU) utilization and discharge destination are shown in Table 4 However, it is less likely that this would have been a factor in inhospital outcomes, which are less frequently influenced by insurance status and patient cost.

| CONCLUSION
In this large cohort of patients hospitalized for acute PE, there were no differences in mortality, discharge to hospice, or ICU utilization between Black and White patients, but Black patients were younger with more cardiometabolic risk factors than White patients, had longer hospitalizations, and more warfarin prescription. While no significant mortality or treatment disparity was found, large-scale studies powered to assess for differences in advanced therapy allocation are still needed to help clinicians better identify patients who stand to benefit from these interventions. Further investigation into racial differences in thromboembolic risk profiles is needed.

ACKNOWLEDGMENTS
This study was investigator-initiated and funded. Alexander E.

Sullivan is supported by the National Institute of General Medical
Science of the National Institutes of Health under award number T32 GM007569. No extramural funding was used to support this work.
The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the paper, and its final contents.
T A B L E 5 Univariable and multivariable regression models for race. Abbreviations: CI, confidence interval; ICU, intensive care unit; IRR, incidence rate ratio; LOS, length of stay; OR, odds ratio.
*Adjusted for age, body mass index, hypertension, congestive heart failure, diabetes, kidney disease, cancer, and prior surgery/trauma.