FIT Completion Rates Back Screening for CRC at Age 45: Daily Dose

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On October 22, 2024, we reported on a study published in Annals of Internal Medicine that evaluated fecal immunochemical test (FIT) completion and yield in patients aged 45 to 49 vs 50 years.

The study

Researchers analyzed rates of FIT completion and coloscopy yield among 267 732 patients from Kaiser Permanente Northern California (80.7%), Washington (9.7%), and Colorado (9.5%) health systems. Participants were divided into 2 cohorts: aged 45 to 49 years (79.9%) and aged 50 years (20.1%). All patients received a FIT kit by mail or during an office visit from January to September 2022. Patients were excluded if they had previously received a FIT kit or underwent colonoscopy, so the FIT kits distributed in 2022 were the first documented CRC screening opportunity for each patient.

The primary outcomes included FIT completion within 3 months of the distribution date; FIT positivity, defined as the proportion of completed FITs with a positive result; follow-up colonoscopy completion, defined as having a colonoscopy within 3 months of a positive FIT result; findings at the follow-up colonoscopy (ie, any adenoma, adenoma with advanced histology, CRC).

The findings

Investigators observed that overall FIT completion across health systems was slightly higher in adults aged 45 to 49 years (38.9% vs 37.5%; adjusted risk ratio [aRR] 1.05, 95% CI 1.04-1.06). They reported similar results among men (37.3% vs 35.7%; aRR 1.06, 95% CI 1.04-1.08) and women (40.4% vs 39.4%; aRR 1.04, 95% CI 1.03-1.06) as well as Asian (47.7% vs 44.9%; aRR 1.07, 95% CI 1.04-1.09) and White (42.4% vs 40.4%; aRR 1.06, 95% CI 1.04-1.08) adults but not those of “other” race (28% vs 36.3%; aRR 0.78, 95% CI 0.62-0.97).

FIT positivity was lower in patients aged 45 to 49 years overall (3.6% vs 4.0%; aRR 0.91, 95% CI 0.84-0.98). Similar rates of a follow-up colonoscopy were also found between the groups (64.9% vs 67.4%; aRR 1.00, 95% CI 0.94-1.05). Adenomas were detected less frequently in patients aged 45 to 49 years (58.8% vs 67.7%; aRR 0.88, 95% CI 0.83-0.95).

Authors' comment

“These findings support recent guideline recommendations to initiate CRC screening at age 45 years and can inform efforts to implement earlier FIT-based CRC screening.”

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