Colorectal Cancer Screening Rates Low Among American Indians, Alaska Natives

Hertel, Wisconsin, St. Croix Tribal Health Clinic, Serving American Indians and Alaska Natives to the highest possible level of health care possible. (Photo by: Education Images/Universal Images Group via Getty Images)
Proximity to a gastroenterologist does not appear to improve the rates among these groups, according to a study.

Proximity to a gastroenterologist has a limited association with improving screening rates for colorectal cancer (CRC) among American Indians and Alaska Natives (AI/AN), researchers reported in the American Journal of Surgery.

The retrospective cohort study assessed the relationship between the density of GI clinicians per state and AI/AN CRC endoscopic screening rates with use of GI locations as a measure for endoscopy access. GI density was determined by calculating the number of GIs per 100,000 individuals.

The Centers for Disease Control’s (CDC) 2016 Behavioral Risk Factor Surveillance System Survey (BRFSS) was used to identify endoscopic screening (colonoscopy within the last 10 years or flexible sigmoidoscopy in the previous 5 years) and nonendoscopic screening (fecal occult blood testing within the past year) for AI/AN aged 50 to 75 years.

The effect of GI density on endoscopic CRC screening for the AI/AN population was assessed using Poisson multivariable analysis with robust error correction.

Among the 480,509 participants in the BRFSS survey, 7238 (1.5%) were AI/AN. Of this group, 235,198 participants were eligible for CRC screening with available age data (aged 50-75 years), of whom 3593 (1.5%) were AI/AN (median age between 60 and 65 years; 55% women).

Significantly more nonHispanic White (NHW) individuals received any CRC screening compared with the AI/AN group (69% vs 54%; chi-square, P <.001), according to the study. The trends were similar for endoscopic screening alone (69.0% NHW vs 53.9% AI/AN, P <.001). Older participants, women, married participants, and those with higher levels of education were more likely to have endoscopic screening, according to the research.

An increased GI density was positively associated with endoscopic screening incidence up to a GI density of about 3.98 GI/100,000 individuals. The second and third GI density quintile relative risk estimates increased to 1.14 (95% CI, 0.92-1.42; P =.23) and 1.31 (1.10-1.56; P =.002), respectively, compared with the first quintile. No meaningful differences beyond this threshold were observed with higher GI density, as the relative risk was 1.37 (1.16-1.63; P <.001) in the fourth GI density quintile and 1.27 (1.02-1.58; P =.04) for the fifth GI density quintile.

Study limitations include the use of GI location as a measure of endoscopy access and absence of actual confirmed endoscopic screening rates. Also, race misclassification is a factor when studying AI/AN, which may have resulted in a significant under-reporting of the true epidemiology of disease.

“AI/AN are a medically underserved and understudied population, with lower CRC screening rates compared to NHW,” stated the study authors. “We found that while a minimum GI density has an important correlation with improving screening rates, this effect diminishes beyond a threshold of 3.7 GI/1000 AI/AN. This implies that many other factors contribute to the disparity in AI/AN CRC screening. Interventions aimed at improving access to CRC for AI/AN patients must account for the multiple barriers to accessing care; increasing GI density alone is not sufficient.”

Reference

Gutnik L, Bleicher J, Davis A, McLeod MC, McCrum M, Scaife C. American Indian/Alaska native access to colorectal cancer screening: does gastroenterologist density matter? Am J Surg. Published online April 28, 2022. doi:10.1016/j.amjsurg.2022.04.023