Impact of comorbidity on colorectal cancer screening cost-effectiveness study in diabetic populations

Abstract

Background: Although comorbidity has been shown to affect the benefits and risks of colorectal cancer (CRC) screening, it has not been accounted for in prior cost-effectiveness analyses of CRC screening.

Objective: To evaluate the impact of diagnosis of diabetes mellitus, a highly prevalent comorbidity in U.S. adults aged 50 and older, on health and economic outcomes of CRC screening.

Design: Cost-effectiveness analysis using an integrated modeling framework.

Data sources: Derived from basic and epidemiologic studies, clinical trials, cancer registries, and a colonoscopy database.

Target population: U.S. 50-year-old population.

Time horizon: Lifetime.

Perspective: Costs are based on Medicare reimbursement rates.

Interventions: Colonoscopy screening at ten-year intervals, beginning at age 50, and discontinued after age 50, 60, 70, 80 or death.

Outcome measures: Health outcomes and cost effectiveness.

Results of base-case analysis: Diabetes diagnosis significantly affects cost-effectiveness of CRC screening. For the same CRC screening strategy, a person without diabetes at age 50 gained on average 0.07-0.13 life years more than a person diagnosed with diabetes at age 50 or younger. For a population of 1,000 patients diagnosed with diabetes at baseline, increasing stop age from 70 years to 80 years increased quality-adjusted life years (QALYs) gained by 0.3, with an incremental cost-effectiveness ratio of $206,671/QALY. The corresponding figures for 1,000 patients without diabetes are 2.3 QALYs and $46,957/QALY.

Results of sensitivity analysis: Cost-effectiveness results are sensitive to cost of colonoscopy and adherence to colonoscopy screening.

Limitations: Results depend on accuracy of model assumptions.

Conclusion: Benefits of CRC screening differ substantially for patients with and without diabetes. Screening for CRC in patients diagnosed with diabetes at age 50 or younger is not cost-effective beyond age 70. Screening recommendations should be individualized based on the presence of comorbidities.

Figure 1.

Cost difference versus QALYs gained as compared with no-screening for different CRC screening cessation strategies per 1,000 individuals, with and without diabetes at age 50 (circle: screening cessation after age 50; pentagram: age 60; diamond: age 70; triangle: age 80; and square: no stop age).