S404 Ischemic Colitis: A Forgotten Rural Health Burden With Persistent Geographic Disparities, 1999-2021

Introduction: Ischemic colitis disproportionately affects older adults and may exhibit geographic variation in mortality outcomes. Rural populations face unique healthcare access challenges that may influence disease-related mortality patterns. This study examines longitudinal trends in ischemic colitis mortality across the rural–urban continuum and identifies geographic disparities in crude mortality rates from 1999 to 2021. Methods: We analyzed CDC WONDER Multiple Cause of Death data from 1999 to 2021 to identify deaths attributed to ischemic colitis (International Classification of Diseases, Tenth Revision codes K55.0 and K55.1). Crude mortality rates per 100,000 population were calculated annually and stratified by 2013 NCHS urbanization categories. Longitudinal trends were assessed across all urbanization tiers. Nonmetropolitan counties, defined as micropolitan and noncore areas, were classified as rural. Rate differences were compared across categories in 2021, the most recent complete data year. Results: From 1999 to 2021, ischemic colitis mortality rates declined in most metropolitan areas but remained elevated in rural regions. Between 2010 and 2021, noncore counties saw a 16.7% decrease in mortality, from 1.2 to 1.0 deaths per 100,000 population. In contrast, large central metropolitan areas maintained consistently lower rates of 0.5 per 100,000 during this period. Despite these improvements, rural areas continued to bear a disproportionate burden. In 2021, noncore counties had double the crude death rate of large central metros (1.0 vs 0.5 per 100,000). A persistent rural–urban mortality gradient was observed, with rates increasing progressively as areas became less urbanized. The highest mortality burden was observed among older adults and in the Southeastern United States. Conclusion: While ischemic colitis mortality has declined in some rural areas over the past decade, a significant rural–urban disparity persists. Rural populations continue to experience twice the mortality risk of residents in large metropolitan areas. Future research should investigate the structural and systemic barriers to optimal ischemic colitis care in rural settings and explore targeted interventions to mitigate geographic disparities in outcomes.