Outcomes of Screening Colonoscopy in Older Adults: A Large Propensity-Matched Real-World Cohort Study

Abstract

Background

The benefits and harms of screening colonoscopy after age 75 remain uncertain. Guidelines endorse individualized decisions given competing risks, but comparative data are limited.

Methods

In the TriNetX US Collaborative Network, adults aged 75–90 years with a colorectal cancer screening encounter were matched 1:1 by colonoscopy within 3 months. Outcomes were assessed at 30 days, 1 year, and 5 years. Sensitivity analyses excluded pre-index anemia and, separately, fecal abnormalities and alarm symptoms; subsequent colonoscopy was counted through 5 years.

Results

Matched cohorts comprised 58 315 pairs at 30 days, 61 497 at 1 year, and 69 821 at 5 years. Colonoscopy increased polyp detection (HR 4.43 [95% CI 4.15–4.73] at 30 days; 1.88 [1.82–1.95] at 5 years) and colorectal cancer detection (4.56 [3.62–5.74]; 1.78 [1.59–1.98]; all p ≤ 0.003). Five-year all-cause mortality was unchanged (HR 1.01 [0.97–1.05]; p = 0.741). Perforation rose at 5 years (HR 1.29 [1.02–1.63]; p = 0.033); gastrointestinal bleeding fell at 1 year (HR 0.90 [0.84–0.97]; p = 0.004). After exclusion of pre-index anemia (70 399 pairs), 5-year HRs remained 1.72 for polyps and 1.52 for cancer. In an indication-restricted cohort also excluding fecal abnormalities, weight loss, abdominal pain, and change in bowel habit (54 300 pairs), the 5-year HRs were 1.59 and 1.32. Subsequent colonoscopy from day 31 to year 5 was not more frequent after index screening (5.8% vs. 6.2%; HR 0.93).

Conclusion

Screening colonoscopy improved polyp and cancer detection but did not reduce 5-year all-cause mortality. The late perforation signal was not explained by more subsequent or therapeutic colonoscopy. Decisions after age 75 should be individualized.