Social Vulnerability and Sickle Cell Disease Mortality in the US

Importance Social determinants of health (SDOH) influence health outcomes, including those of sickle cell disease (SCD), despite advancements in treatments like disease-modifying therapies. Objective To investigate the association of SDOH with SCD mortality rates from 2016 to 2020. Design, Setting, and Participants This cross-sectional study combined county-level data from the Centers for Disease Control and Prevention and Agency for Toxic Substances and Disease Registry Social Vulnerability Index (SVI) with SCD mortality data from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database from January 1, 2016, to December 31, 2020. US counties were divided into 4 quartile (Q) models according to their SVI scores. Deaths from SCD in the US among patients of all ages were included. Data analysis occurred from March to April 2024. Exposure SVI score. Main Outcomes and Measures Age-adjusted mortality rates (AAMRs) per 1 000 000 individuals were measured. Rate ratios (RRs) were obtained by comparing county-specific AAMRs of SVI-Q4 with SVI-Q1. Results From 2016 to 2020, among a total population of 1 633 737 771 individuals, there were 2635 deaths from SCD (1289 male 49.1% and 1336 female 50.9%). There were 1480 deaths in Q4, 687 deaths in Q3, 344 deaths in Q2, and 114 deaths in Q1. Higher SVI was associated with 2.11 excess deaths per 1 000 000 individuals (RR, 4.90; 95% CI, 4.81-5.00). Similar trends were seen for both males (RR, 4.56; 95% CI, 4.44-4.69) and females (RR, 5.85; 95% CI, 5.68-6.03). Middle-aged patients with SCD had the highest mortality rate in Q4, with 3.45 excess deaths per 1 000 000 individuals (RR, 4.97; 95% CI, 4.85-5.09). Higher SVI was associated with 2.29 excess deaths per 1 000 000 individuals in African American individuals with SCD (RR, 1.24; 95% CI, 1.22-1.27]). In White individuals with SCD, higher SVI was associated with 0.12 excess deaths per 1 000 000 individuals (RR not available due to unreliable data in Q1). When stratifying by census region, the highest level of SCD-related mortality was in the Northeast, with higher SVI associated with 3.16 excess deaths per 1 000 000 individuals (RR, 8.02; 95% CI, 7.66-8.40). Conclusions In this cross-sectional study of the association of SVI with SCD mortality rates, higher SVI was associated with higher SCD mortality across US counties. These findings underscore the importance of addressing social determinants of health to improve mortality outcomes among patients with SCD.