Trends in Heart Failure-related Cardiovascular Mortality in Rural Versus Urban Counties in the United States, 2011-2018

Abstract

Introduction Mortality rates due to heart failure (HF) have increased since 2011, but estimates of heterogeneity at the county-level in HF-related mortality are not known. Differences between rural and urban counties and the impact of county-level factors on HF-related mortality are needed to inform public health strategies. Hypotheses Substantial variation in HF-related mortality trends between 2011-2018 exists by rural-urban designation. In addition, county-level factors account for a large proportion rural-urban differences in HF-related mortality rates. Methods We queried CDC WONDER to identify HF deaths between 2011-2018 defined as any mention of HF (I50) on the death certificate and cardiovascular disease (I00-78) as the underlying cause of death. First, we calculated age-adjusted mortality rates (AAMR) and examined trends stratified by rural-urban status (defined using 2013 NCHS Urban-Rural Classification Scheme), age (35-64 and 65-84 years), and race-sex subgroups per year. Second, we combined all deaths from 2011-2018 and estimated incidence rate ratios (IRR) in HF-related mortality for rural versus urban counties using multivariable negative binomial regression models with adjustment for sociodemographic factors, risk factor prevalence, and physician density. Results Between 2011-2018, AAMRs were consistently higher for rural compared with urban counties (e.g., 73.2 [95% CI: 72.2-74.2] vs. 57.2 [56.8-57.6] in 2018, respectively). The highest AAMR was observed in rural black men (131.1 [123.3-138.9] in 2018), and the greatest increases in HF-related mortality occurred in rural black men, age 35-64 years (+6.1%/year). Unadjusted models demonstrated significantly higher HF-related mortality in rural versus urban counties across the entire study period (IRR = 1.67 [95% CI: 1.57-1.78] and 1.16 [95% CI: 1.13-1.18] for younger and older adults, respectively). The rural-urban IRR was significantly attenuated after adjustment for county-level factors among both younger (1.10 [1.04-1.16]) and older adults (1.04 [1.02-1.07]). Conclusions Differences in county-level factors account for a significant amount of the observed variation in HF-related mortality between rural and urban counties.