Multilevel small area estimation for county-level prevalence of colorectal cancer screening test use in the United States using 2018 data

Abstract

Purpose—National screening estimates mask county-level variations. We aimed to generate county-level colorectal cancer (CRC) screening prevalence estimates for 2018 among adults aged 50–75 years and identify counties with low screening prevalence. Methods—We combined individual-level county data from the 2018 Behavioral Risk Factor Surveillance System (BRFSS) (n = 204,947) with the 2018 American Community Survey county poverty data as a covariate, and the 2018 U.S. Census county population count data to generate county-level prevalence estimates for being current with any CRC screening test, colonoscopy, and home stool blood test. Because BRFSS is a state-based survey, and because some counties did not have samples for analysis, we used correlation coefficients to test internal consistency between model-based and BRFSS state estimates. Results—Correlation coefficients tests were ≥0.97. Model-based national prevalence for any test was 69.9% (95% CI, 69.5% –70.4%) suggesting 30% are not current with screening test use. State mean estimates ranged from 62.1% in Alaska and Wyoming to 76.6% in Maine and Massachusetts. County mean estimates ranged from 42.2% in Alaska to 80.0% in Florida and Rhode Island. Most tests were performed with colonoscopy. Conclusions—Estimates across all U.S. counties showed large variations. Estimates may be informative for planning by states and local screening programs.