Colorectal screening among average risk individuals in the United States, 2015-2018

Colorectal cancer screening rates are important metrics for public health and quality indicators for health care systems; however, published estimates of colorectal cancer screening rates often include both high-risk and average-risk patients, and the use of different epidemiologic methods makes between-study comparisons tenuous. The objective of this study was to measure the proportion of average-risk American adults who are up to date with colorectal cancer screening guidelines and examine the impact of evaluation methods on screening rate estimates. This repeated cross-sectional study used administrative claims to identify individuals aged 50-75 years between 2015 and 2018 with ≥ 1-year of continuous health plan enrollment. Sensitivity analyses to replicate prior studies in the literature included: 1) retrospective cohort study requiring ≥ 10 years of continuous enrollment to identify the most current screening rates (2018), and 2) inclusion of individuals with higher colorectal cancer risk. A total of 2,579,898; 2,948,064; 3,312,882; and 2,752,864 individuals were included in the 2015, 2016, 2017, and 2018 populations, respectively. In the cross-sectional sample, the proportion of individuals with up-to-date colorectal cancer screening was 51.8%, 51.3%, 51.0%, and 51.1% in 2015, 2016, 2017, and 2018, respectively. The inclusion of high-risk individuals increased estimates approximately 37%. Using a retrospective cohort design, 67.5% of average-risk individuals were up to date in 2018. This study demonstrated the impact of methodological differences on rate estimates. Efforts to track screening rates require transparency in measurement methods to accurately evaluate progress in improving rates.