Assessing the impact of screening colonoscopy on mortality in the medicare population

Abstract

Background: Some have recommended against routine screening for colorectal cancer (CRC) among patients ≥75 years of age, while others have suggested that screening colonoscopy (SC) is less beneficial for women than men. We estimated the expected benefits (decreased mortality from CRC) and harms (SC-related mortality) of SC based on sex, age, and comorbidity.

Objective: To stratify older patients according to expected benefits and harms of SC based on sex, age, and comorbidity.

Design: Retrospective study using Medicare claims data.

Participants: Medicare beneficiaries 67-94 years old with and without CRC.

Main measures: Life expectancy, CRC- and colonoscopy-attributable mortality rates across strata of sex, age, and comorbidity, pay-off time (i.e. the minimum time until benefits from SC exceeded harms), and life-years saved for every 100,000 SC.

Key results: Increasing age and comorbidity were associated with lower CRC-attributable mortality. Due to shorter life expectancy and CRC-attributable mortality, the benefits associated with SC were substantially lower among patients with greater comorbidity. Among men aged 75-79 years with no comorbidity, the number of life-years saved was 459 per 100,000 SC, while men aged 67-69 with ≥3 comorbidities had 81 life-years saved per 100,000 SC. There was no evidence that SC was less effective in women. Among men and women 75-79 with no comorbidity, number of life-years saved was 459 and 509 per 100,000 SC, respectively; among patients with ≥3 comorbidities, there was no benefit for either men or women.

Conclusions: Although the effectiveness of SC was equivalent for men and women, there was substantial variation in SC effectiveness within age groups, arguing against screening recommendations based solely on age.

Figure 1

Number of life-years saved by sex, age, and comorbidity strata.

Figure 2

Screening colonoscopy decision rule.