Association between County-level Gastroenterologist and General Surgeon Densities, and Colorectal Cancer Mortality in the United States: An Evaluation of a Nationwide Registry

Background: County-level density of providers of colorectal cancer (CRC) screening and treatment may influence its outcomes. We hypothesized that an increase in the density of general surgeons and gastroenterologist in counties is associated with a reduction in CRC mortality rate. Methods: We analyzed a linked Surveillance Epidemiology and End Results 2006-2010and Area Resource File 2009 dataset comprising 2,608 counties. We calculated county-specific densities of gastroenterologists and general surgeons. Univariate and multivariate linear regression analyses were performed separately to assess associations between the county level age-adjusted colorectal cancer mortality rates and gastroenterologist, general surgeon densities, and other county level socioeconomic predictors. Results: Gastroenterologist densities of 0.1 to 1.5, 1.5 to 3.0 and greater than 3.0 per 100,000 people were associated with a reduction of 1.32(95%CI 0.39-2.24), 0.99(95%CI 0.38-1.57) and 1.47(95%CI 0.94-2.01) per 100,000 CRC mortality respectively compared to counties without a gastroenterologist. Also, general surgeon densities of 0.1 to 5.0 and 5.1 to 10.0 per 100,000 people were associated with a reduction of 0.95(95%CI 0.38-1.52) and 0.85(95%CI 0.35-1.38) per 100,000 CRC mortality respectively, compared to counties without a general surgeon. An increase in median household income was associated with a reduction in CRC mortality across counties. Conclusion: This study highlights geographic disparities in CRC mortality rates in this country, and their association with the distribution of specialists who provide screening and/or treatment services for this disease, and median household income.