Dr. Hansol Kang

Prevalence of Inflammatory Bowel Disease Across States: Estimates Based on Claims Database

Dr. Hansol KangResident Research Spotlight
Inflammatory Bowel Diseases, 2026View Publication →

Study Overview

Despite the United States having among the highest rates of inflammatory bowel disease (IBD) globally, geographic estimates at the state level have remained scarce, largely because the U.S. lacks a unified health system or national disease registry. In this brief report, Dr. Hansol Kang and colleagues addressed this gap by applying data from a previously validated national pooled administrative claims analysis to generate race-weighted, state-specific prevalence estimates for both Crohn's disease (CD) and ulcerative colitis (UC).

The team drew on four large insurance datasets (Medicare, Medicaid, and two commercial plans: Optum CDM and HealthCore) spanning over 14 million individuals with at least 4 years of continuous enrollment. To account for the substantial racial diversity across states, census-derived race-specific weights were applied to the national prevalence estimates, producing age-, sex-, and race-standardized figures for all 50 states and the District of Columbia.

Key Findings

  • IBD prevalence per 100,000 population ranged from 571 in Hawaii to 877 in Maine, with Northern and Eastern states consistently showing higher rates.
  • The highest absolute numbers of individuals with IBD were in California, Texas, Florida, and New York, reflecting population size rather than disease burden per capita.
  • States with higher IBD prevalence per 100,000 tended to have a greater proportion of White residents, consistent with known racial disparities in IBD epidemiology.
  • The ratio of UC to CD was generally similar across states, ranging from 1.18 in Utah to 1.31 in Maine.
  • California and Texas ranked 1st and 2nd for total IBD population but 49th and 50th for IBD prevalence per 100,000, underscoring why raw counts can be misleading without population adjustment.

Clinical Significance

State-level IBD prevalence data have direct implications for health system planning. Regions with higher per-capita burden may require greater gastroenterology workforce allocation, expanded infusion and multidisciplinary care infrastructure, and targeted public health investment. Conversely, high-population states with lower per-capita rates still carry enormous absolute disease burdens that strain resources in different ways.

These estimates also support health equity initiatives: states with lower proportions of White residents may be systematically undercounting IBD burden if surveillance methods are not race-adjusted. This study provides a replicable framework for monitoring geographic and demographic trends in IBD over time, and for identifying where access to specialty care may be most needed.