Introduction: Ulcerative colitis (UC) and Crohn’s disease (CD) are the two major forms of inflammatory bowel disease; both require specialized care. We aimed to describe the geographic distributions of patients with UC/CD and gastrointestinal specialists across the US and identify geographic disparities in access to specialist care.
Methods: For each 3-digit ZIP code and each state in the US (including Washington, DC), we calculated the number of patients with UC/CD per 100,000 people, the number of gastroenterologists per 100,000 people, and the number of gastroenterologists per 100 patients with UC/CD. Patients with UC/CD were identified using IQVIA open-source medical claims data for 2022, which included claims from Medicaid, Medicare, and commercial health plans; inclusion required UC or CD diagnosis codes (in any position) on ≥2 outpatient claims ≥30 days apart or 1 inpatient claim. Provider specialty and practice location were identified using the 2022 National Provider Identifier registry. ZIP-level characteristics were obtained from 2020 US Census data.
Results: Data were analyzed from 903 3-digit ZIP codes and all 50 states + Washington, DC. In total, 520,020 patients with UC/CD and 28,754 gastroenterologists were identified. Patient density varied across states, from 58.2 (New Mexico) to 337.1 (Maine) per 100,000 people. On average, there were 5.5 gastroenterologists per 100 patients with UC/CD. Provider density varied across states, from 2.3 (Kansas) to 12.2 (Hawaii) gastroenterologists per 100 patients. The Midwest and the Southwest Border regions generally had the lowest density of gastroenterologists per 100 patients. Across the US, 115 3-digit ZIP codes had zero gastroenterologists per 100 patients; 74% of these ZIP codes were in majority rural areas and >40% of these ZIP codes had a poverty rate >25% (defined as household income ≤150% of the poverty line). ZIP codes with ≥5 gastroenterologists per 100,000 people tended to have lower poverty rates, be more urban, and have greater proportions of Hispanic or Black populations than ZIP codes with < 1 or 1 to < 5 gastroenterologists per 100,000 people.
Discussion: Densities of patients with UC/CD and gastroenterologists varied drastically across US states and 3-digit ZIP codes. Gastroenterologist density was lower in Midwest and Southwest regions and in areas that were more rural and had greater poverty, suggesting geographic and socioeconomic disparities in access to specialist care for UC/CD.
Figure: Densities of gastroenterologists and patients with UC/CD by 3-digit ZIP code. Calculated density of (A) gastroenterologists per 100 patients with UC/CD, (B) patients with UC/CD per 100,000 population, and (C) gastroenterologists per 100,000 population in each US 3-digit ZIP code. Abbreviations: CD, Crohn’s disease; UC, ulcerative colitis.
Note: The table for this abstract can be viewed in the ePoster Gallery section of the ACG 2024 ePoster Site or in The American Journal of Gastroenterology's abstract supplement issue, both of which will be available starting October 27, 2024.
Magdaliz Gorritz, MPH1, Navneet Upadhyay, MS, PhD2, Rifat Tuly, MPH, MS3, Nicholas Bires, PharmD2, Michael Hull, MS4, Casey Chapman, MD5. P4401 - Geographic Disparity in Access to Specialist Care for Ulcerative Colitis and Crohn’s Disease in the US, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.
