Abstract
Introduction: Pulmonary Embolism (PE) remains a leading cause of mortality in adults in U.S. contributing to an estimated 100,000 cases annually. The role of social vulnerability in PE related mortality is unclear. Social vulnerability describes the risk experienced by communities for adverse outcomes due to underlying demographic and socioeconomic factors. The Centers for Disease Control and Prevention's Social Vulnerability Index (CDC SVI), which assesses county-level social vulnerability, is linked to increased mortality in stroke and sickle cell disease, yet its role in PE-related mortality remains uninvestigated. In this study, we hypothesize that socially vulnerable counties, will be at risk for higher PE-related mortality.
Methods: We conducted a retrospective cross-sectional study on adults ≥ 25 years using CDC's Wide‐Ranging Online Data for Epidemiologic Research (WONDER) underlying cause database and accessed mortality data for all U.S. counties between 2016-2020. PE-related deaths were identified usingICD-10 code I26. We calculated average PE-related crude mortality rates (PE-CMR) for each available county per 100,000 population and linked it to CDC SVI data for the corresponding years. Briefly, SVI measures vulnerability in four domains - (1) socioeconomic status, (2) household composition & disability, (3) minority status & language, and (4) housing type & transportation and assigns each county a percentile score from 0 to 1. Counties were then divided into 4 quartiles according to their SVI scores. Higher SVI scores indicate higher vulnerability. The associations between PE-CMR, SVI and its 4 domains were analyzed by Poisson regression. Analyses were performed using IBM SPSS Statistics (version 29.0.2.0), and a p-value ≤ 0.05 was considered significant.
Results: The total number of PE-related deaths cover the five-year period were 44,571. The overall PE-related CMR per 100,000 people was 3.84 in 2016, 3.89 in 2017, 3.91 in 2018, 3.79 in 2019, and 4.1 in 2020. A total of 980 counties had available SVI and PE mortality data, accounting for 81.6% deaths during the study period. Mean PE- CMR was 7.62 per 100,000 (95% Confidence Interval (CI): 6.68-8.55) in the highest quartile of SVI (most vulnerable) and was 4.99 per 100,000 (95% CI: 4.64-5.35) in the lowest quartile (least vulnerable). A simple linear regression analysis revealed a positive association between overall SVI and CMR (B = 3.26, SE = 0.68, β = 0.153, p < .001), indicating that higher social vulnerability is associated with higher PE mortality.
A separate Poisson regression analysis was done to examine the effect of the four SVI domains on PE-CMR, adjusting for population size. Higher vulnerability in socioeconomic status (Rate ratio (RR) = 1.08, 95% CI: 1.01–1.15, p = .036) and household/disability domain (RR = 2.71, 95% CI: 2.56–2.87, p < .001) was associated with higher PE-CMR, while higher vulnerability in language/minority status was associated with lower mortality (RR = 0.23, 95% CI: 0.22–0.24, p < .001); Vulnerability in housing type & transportation was not a significant contributor to PE-related CMR.
Discussion: In this cross-sectional study, we demonstrate that SVI is a predictor of county-level PE-related mortality in the U.S. Furthermore, we show that higher vulnerability in socioeconomic and household/disability domains is associated with higher PE-related mortality. Interestingly, we noted that higher vulnerability language/minority status was protective. The strength of our study is that we focused only on cases where the sole cause of death was PE, allowing us to examine the role of SVI and PE without confounding. Limitations include potential bias due to exclusion of counties with fewer than 10 deaths), lack of individual-level clinical data, and use of administrative codes without diagnostic confirmation. We also did not conduct age-adjusted analyses but is the subject for future studies.
Future studies should test if social vulnerability interacts with individual risk factors to increase PE-related mortality and develop targeted interventions in the most at-risk communities.
