Factors Affecting Adherence in a Pragmatic Trial of Annual Fecal Immunochemical Testing for Colorectal Cancer

Abstract

Background: Colorectal cancer screening by fecal immunochemical test (FIT) reduces the burden of colorectal cancer. However, effectiveness relies on annual adherence, which presents challenges for clinic staff and patients.

Objective: Describe FIT return rates and identify factors associated with FIT adherence over 2 years in a mailed FIT outreach program in federally qualified health centers.

Design: Observational study nested in the Strategies and Opportunities to Stop Colon Cancer in Priority Populations (STOP CRC) trial. Five thousand one hundred ninety-five patients had an initial FIT order and were followed for ≥ 2 years (3574 also had a FIT order in the second year).

Main measures: FIT return percent in each year and patient- and neighborhood-level characteristics associated with FIT adherence.

Key results: Overall, the proportion of FIT orders that were completed was 46% in the patients' first year and 41% in the patients' second year. Of the 5195 patients with a FIT order in year 1, 3574 (69%) also had a FIT order in year 2 (71% of year 1 adherers and 67% of year 1 non-adherers, p = 0.009). Among those with a FIT order in the second year, the FIT return rate was about twice as high among those who were adherent in the first year (952/1674, or 57%) as among those who were not (531/1900, or 28%, p < 0.0001). Patient-level characteristics associated with higher odds of FIT return were a history of FIT screening at baseline, age over 65 (vs 50-65), no current tobacco use, recent receipt of a mammogram or flu vaccine, Asian ancestry (compared to non-Hispanic white), and non-English preference. The only neighborhood factor associated with lower FIT return rate was patient's larger residential city size.

Conclusion: Our findings can inform the customization of programs to promote FIT return among patients who receive care at federally qualified health centers.

Trial registration: http://www.clinicaltrials.gov.

Keywords: cancer; colorectal; fecal immunochemical test; screening.

Figure 1

Inclusion in the analytic sample of FIT screening adherence. *Window of FIT order consideration: after patient eligibility, after start of clinic intervention activities, and at least 2 years prior to end of clinic’s intervention activities. FIT, fecal immunochemical test; FS, flexible sigmoidoscopy; STOP CRC, Strategies and Opportunities to Stop Colon Cancer in Priority Populations.