Racial disparities exist across age groups in Illinois for pulmonary embolism hospitalizations

Introduction

Pulmonary embolism (PE) is an important cause of cardiovascular morbidity and mortality, contributing to over 185,000 hospitalizations and 35,000 deaths annually.¹ Risk of PE increases with age and may be higher among non-Hispanic (NH) black adults. However, conflicting data on racial disparities exists in PE,² and it is unknown whether disparities are similar across age groups. Therefore, our objectives were to describe contemporary rates of hospitalization for PE and examine differences by age and race/ethnicity.

Methods

We analyzed administrative, visit-level data from the Illinois Health and Hospital Association’s Comparative Health Care and Hospital Data Reporting Services (COMPdata) from 204 non-federal hospitals in Illinois (IL). We identified hospitalizations of NH white and NH black IL residents ≥ 18 years with a principal diagnosis of PE according to the International Classification of Diseases, Tenth Revision (I26) from 2016–2018.

We estimated IL population totals for each subgroup from the American Community Survey (ACS), 2013–2017. Using negative binomial regression models, we calculated rates of hospitalization for principal diagnosis of PE per 10,000 IL residents, overall and stratified by age category, race/ethnicity, and sex. We quantified rate ratios (RR) of PE hospitalization in NH blacks compared with NH whites, adjusting for age and sex. All analyses were completed using SAS version 9.4 (SAS Institute Inc., Cary, NC). Our study was deemed exempt by our Institutional Review Board.

Results

Of 22,244 hospitalizations with a principal diagnosis of PE, 54.4% were female, 70.5% NH white and 24.3% NH black. The mean (SD) age was 63 (17) years. Approximately 50% of patients hospitalized with a principal diagnosis of PE were younger than 65 years. In all age groups, NH black men and women had higher rates of PE hospitalization (14.5 [2.0–103.2] and 16.5 [2.3–117.5] per 10,000 population, respectively) compared with NH white men and women (8.8 [1.2–62.8) and 9.3 [1.3–66.0] per 10,000 population, respectively) (Figure). In patients <65 years, NH black men and women had higher rates of PE hospitalization (11.6 [1.6–82.8] and 12.6 [1.8–89.6] per 10,000 population, respectively), compared with NH white men and women (5.6 [0.8–39.8] and 5.1 [0.7–36.4] per 10,000 population, respectively). Similarly, in older adults (≥65 years), NH black men and women had higher rates of PE hospitalization (29.8 [4.2–212.2] and 32.0 [4.5–227.7] per 10,000 population, respectively) compared with older NH white men and women (20.0 [2.8–142.3] and 20.5 [2.9–145.5] per 10,000 population, respectively). Overall, we found that NH Blacks were almost twice as likely to be hospitalized for PE compared with NH Whites (RR 1.9, 95% CI: 1.5–2.3) after adjusting for age and sex.

Figure.

Rate of hospitalization for primary diagnosis of PE per 10,000 residents stratified by age and race/ethnicity-sex groups

* Whereby p<0.001 represents the significant differences between non-Hispanic (NH) black compared with white patients hospitalized with PE

Discussion

Our study demonstrates that half of all PE hospitalizations occur in patients <65 years. Hospitalization rates for PE are higher among NH black compared with NH white adults in both younger (<65 years) and older (≥65 years) age groups. Racial disparities are particularly pronounced in younger adults, with PE hospitalization rates for NH black men and women nearly double those for white men and women.

Our data are consistent with a prior study that used inpatient claims data to show that for adults older than 65 years hospitalized with principal diagnosis of PE, black patients had higher rates of hospitalization compared with white patients.³ In contrast, observational cohort studies with relatively older participants (54–73 years) did not identify racial differences in PE hospitalization rates.⁴

Our study expands upon prior work by showing that racial disparities in the US are more pronounced in younger adults. The underlying causes for PE disparities may be related to risk factor burden, underlying genetic risks, differences in pathophysiology of venous thromboembolism, or, likely, the interplay of all of these factors. Interestingly, disparities in young black adults have been reported in other cardiovascular diseases, reflecting underlying common clinical risk factors, such as obesity, as well as upstream social determinants of health,⁵ and are likely applicable in PE disparities as well.

A key strength of our study is the use of a large group of hospitals with a diverse population that is fairly representative of the US population. We limited our analysis to principal diagnosis of PE, as diagnosis for those who were not admitted or who had secondary diagnosis of PE may be less reliable. Limitations to our study include reliance on ICD coding. However, this is unlikely to disproportionately affect one race/ethnic group.

In conclusion, we demonstrate that younger adults (<65 years) comprise 50% of PE hospitalizations. Racial disparities exist among contemporary hospitalizations for PE across the lifespan and are particularly pronounced in younger adults. Multi-level interventions targeting biological risk factors as well as upstream root causes (e.g. systemic and structural racism) are needed to ultimately mitigate health inequities related to PE.