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

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.

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.

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).

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

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.

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

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