Urban-Rural Differences in Acute Kidney Injury Mortality in the United States.

Introduction: Acute kidney injury (AKI) is associated with increased mortality. AKI-related mortality trends by U.S. urban and rural counties were assessed.

Methods: In the cross-sectional study, based on the Centers for Disease Control and Prevention WONDER (Wide-ranging ONline Data for Epidemiologic Research) Multiple Cause of Death data, age-standardized mortality with AKI as the multiple cause was obtained among adults aged ≥25 years from 2001-2020, by age, sex, race and ethnicity, stratified by urban-rural counties. Joinpoint regressions were used to assess trends from 2001-2019 in AKI-related mortality rate. Pairwise comparison was used to compare mean differences in mortality between urban and rural counties from 2001-2019.

Results: From 2001-2020, age-standardized AKI-related mortality was consistently higher in rural than urban counties. AKI-related mortality (per 100,000 population) increased from 18.95 in 2001 to 29.46 in 2020 in urban counties and from 20.10 in 2001 to 38.24 in 2020 in rural counties. In urban counties, AKI-related mortality increased annually by 4.6% during 2001-2009 and decreased annually by 1.8% until 2019 (p<0.001). In rural counties, AKI-related mortality increased annually by 5.0% during 2001-2011 and decreased by 1.2% until 2019 (p<0.01). The overall urban-rural difference in AKI-related mortality was greater after 2009-2011. AKI-related mortality was significantly higher among older adults, men, and non-Hispanic Black adults than their counterparts in both urban and rural counties. Higher mortality was concentrated in rural counties in the Southern United States.

Conclusions: Multidisciplinary efforts are needed to increase AKI awareness and implement strategies to reduce AKI-related mortality in rural and high-risk populations.