Racial Disparities in Colorectal Cancer Mortality: the Role of Endoscopy Wait-Time and Stage at Diagnosis.

Abstract

In Western Washington (WA), colorectal cancer (CRC) mortality between 2012 and 2016 was highest in American Indian/Alaska Natives (AI/AN) and African-Americans (AA) at 20.7 and 18.7, respectively, compared with non-Hispanic Whites at 14.1/100,000 people. We hypothesized that time from billed encounters for CRC-associated symptoms to endoscopy completion or CRC stage at diagnosis contributed to observed differences. Using administrative insurance claims linked to WA cancer registry data, we performed a retrospective cohort study of patients diagnosed with CRC between 2011 and 2017, with continuous insurance for 15months prior to diagnosis and a billed encounter for CRC-associated symptoms. We determined the wait-time (days) and stage at diagnosis and conducted logistic regression analysis to identify the factors associated with endoscopy completion. Of the 3461 CRC patients identified, 57% had stage 2 or 3 disease with no differences in stage by race, and 84% completed an endoscopy after a billed encounter for CRC-associated symptoms. The median wait-time to endoscopy was 52days (IQR 14-218) without differences by race. Compared with patients diagnosed with stage 1 CRC, patients with stage 4 CRC were more likely to complete an endoscopy within the first quartile of time (22.2% vs. 17.4%, p< 0.01). Living arrangement, insurance type, and comorbidity, but not race, were significant factors associated with endoscopy completion. We found no statistically significant differences in time from billed CRC-associated symptoms to endoscopy completion or in CRC stage among AA and AI/AN compared to Whites. This suggests that other factors are more likely to contribute to observed mortality disparities.