Association of County-degree Social Vulnerability with Chronic Respiratory Disease Mortality in the United States

Abstract

Rationale: Chronic respiratory diseases, the third leading cause of death worldwide, have been associated with significant morbidity, mortality, and increased economic burden that make a profound impact on individuals and communities. However, limited research has delineated complex relationships between specific sociodemographic disparities and chronic respiratory disease outcomes among U.S. counties. Objectives: To assess the association of county-level sociodemographic vulnerabilities with chronic respiratory disease mortality in the United States. Methods: Chronic respiratory disease mortality data among U.S. counties for 2014-2018 was obtained from the CDC WONDER (Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research) database. The social vulnerability index (SVI), including subindices of socioeconomic status, household composition and disability, minority status and language, and housing type and transportation, is a composite, percentile-based measure developed by the CDC to evaluate county-level sociodemographic vulnerabilities to disasters. We examined county-level sociodemographic characteristics from the SVI and classified the percentile rank into quartiles, with a higher quartile indicating greater vulnerability. The associations between chronic respiratory disease mortality and overall SVI, its four subindices, and each county characteristic were analyzed by negative binomial regression. Results: From 2014 to 2018, the age-adjusted mortality per 1,000,000 population attributed to chronic lower respiratory disease was 406.4 (95% confidence interval [CI], 405.5-407.3); chronic obstructive pulmonary disease (COPD), 393.7 (392.8-394.6); asthma, 10.0 (9.9-10.2); interstitial lung disease (ILD), 50.5 (50.1-50.8); idiopathic pulmonary fibrosis (IPF), 37.0 (36.7-37.3); and sarcoidosis, 5.3 (5.2-5.4). Counties in the higher quartile of overall SVI were significantly associated with greater disease mortality (chronic lower respiratory disease, incidence rate ratios: fourth vs. first quartile, 1.43 [95% CI, 1.39-1.48]; COPD, 1.44 [1.39-1.49]; asthma, 2.06 [1.71-2.48]; ILD, 1.07 [1.02-1.13]; IPF, 1.14 [1.06-1.22]; sarcoidosis, 2.01 [1.44-2.81]). In addition, higher mortality was also found in counties in the higher quartile of each subindex and most sociodemographic characteristics. Conclusions: Chronic respiratory disease mortalities were significantly associated with county-level sociodemographic determinants as measured by the SVI in the United States. These findings suggested sociodemographic determinants may add a considerable barrier to establishing health equity. Multidegree public health strategies and clinical interventions addressing inequitable outcomes of chronic respiratory disease should be developed and targeted in areas with greater social vulnerability and disadvantage.

Keywords: United States; chronic respiratory diseases; health disparity; social vulnerability index.