Disparities in sickle cell disease related mortality in the US-Mexico border region from 1999 to 2020: A CDC wonder Study

Abstract

Abstract Background: Sickle cell disease (SCD) is an inherited hemoglobinopathy caused by a point mutation in the β-globin gene, resulting in hemoglobin S production. Under hypoxic conditions, hemoglobin S polymerizes, leading to erythrocyte sickling, chronic hemolysis, and vaso-occlusion. SCD primarily affects individuals of African descent and is one of the most common genetic disorders in the United States. It is associated with significant morbidity, and reduced life expectancy. This study aims to analyze annual trends and sociodemographic factors in SCD-related mortality in the US-Mexico Border Region from 1999 to 2020, to assess public health initiatives, and highlight areas needing targeted intervention. This will guide future directions to improve patient outcomes and public health approaches for prevention and treatment strategies. Methods: The mortality trends among individuals aged <1-85+ with SCD were analyzed using data from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiological Research (CDC WONDER) database, where SCD was a contributing or the underlying cause of death. Codes D57.0 (sickle-cell anemia with crisis), D57.1 (sickle-cell anemia without crisis), D57.2 (double heterozygous sickling disorders), and D57.8 (other sickle-cell disorders) in the International Classification of Disease, tenth revision (ICD-10) were used to identify the data. Crude and age-adjusted mortality rates (AAMRs) per 100,000 people were extracted. Annual percent changes (APCs) and average annual percent changes (AAPCs) in AAMRs with 95% CI were obtained using joint point regression analysis. Data were stratified across different demographic (sex, race/ethnicity, and age) and geographic (U.S. border and non-border regions) subgroups. Results: Between 1999 and 2020, 17,711 documented deaths were reported from SCD in the US-Mexico Border Region. The overall AAMR for SCD-related mortality increased in the US-Mexico Border Region from an adjusted rate (AR) of 2.7 in 1999 to 3.12 in 2020. The overall AAMR from 1999-2020 was 2.62 (AAPC: 0.82; 95% CI: -0.30 to 1.96). Males and females had comparable overall AAMRs from 1999 to 2020 (2.62 vs 2.63). Males had an AAPC of 0.62 (95% CI: -0.39 to 1.66) while females had an AAPC of 0.31 (95% CI: -0.15 to 0.77). The AAMR for males increased from 2.86 to 3.2 from 1999-2020. The AAMR for females increased from 2.57 to 3.07 in this 21-year period. The mortality rate showed racial and ethnic variations. The non-Hispanic (NH) Black or African-American population had the highest overall AAMR of 19.9 (AAPC: 0.30; 95% CI: -0.82 to 1.44), followed by the Hispanic or Latino population with an AAMR of 0.74, and Whites and the American Indian or Alaska Native population with an AAMR of 0.09. AAMR also varied by region. U.S. non-border regions had higher AAMR (2.68) compared to the US-Mexico border regions (0.71). Age-wise stratification showed that the 23–34 years age group had a CMR of 0.39, the 35–44 years group had a CMR of 0.43, and the 45–54 years group had a CMR of 0.40, accounting for the most deaths due to SCD in the U.S. border regions. Majority of these deaths (11,306 deaths) occurred in the medical inpatient facilities accounting for 63.84% of the mortality burden. This was followed by the decedent's home (2,498 deaths), where 14.10% of the total deaths from SCD took place. Conclusion: The mortality rates from sickle cell disease generally increased in the US-Mexico Border Regions over the 21-year study period from 1999-2020. Significant demographic and geographic disparities in SCD-related mortality persist, with a greater burden observed in NH Black population, middle-aged individuals, and those residing in non-border U.S. regions. This highlights the need for further investigation and the development of targeted treatment strategies.