Statistical analysis
CRC
REGRESSION
To assess effectiveness of the intervention, we calculated mailed FIT return at 60 days and 6 months. For the nested trial, we conducted an intention-to-treat analysis (i.e., all participants randomized included in the analysis). To compare FIT return between the two nested intervention arms (enhanced vs. plain envelope), we used a chi-squared test and calculated confidence intervals. We also used logistic regression to adjust for baseline demographic characteristics (sex, race/ethnicity, insurance). Finally, we calculated the difference in overall CRC screening at the FQHC clinic site in a 6-month period (February–August 2022)—accounting for all CRC screening modalities and measured using EMR data—and noted the types of modalities used. All tests were 2-sided at alpha level 0.05 unless otherwise specified. Statistical analyses were conducted using Stata software, version 17.0 (StataCorp, College Station, TX).