Cost Differences After Initial CT Colonography Versus Optical Colonoscopy in the Elderly

To compare differences in Medicare costs 1 year after initial computed tomographic colonography (CTC) or initial optical colonoscopy (OC).

We performed a retrospective cohort study of asymptomatic Medicare outpatients aged ≥ 66 years who received initial CTC (n = 531) or OC (n = 17,593) between January 2007 and December 2008; initial OC patients were matched on county of residence and year of screening. Outcomes included differences in total inpatient and outpatient Medicare costs 1 year after initial CTC or OC and differences in outpatient testing of potential findings in the colon, abdomen, pelvis, and lungs.

Higher adjusted costs per patient were revealed in the year after initial CTC compared to initial OC for outpatient testing related to potential colonic ($50; 95% confidence interval [CI], $12-$88; P = .010) and extracolonic findings ($64; 95% CI, $23-$106; P = .002). However, there were no differences in adjusted total costs per patient in the year after either modality ($2065; 95% CI, $1672-$5803; P = .28). Similarly, adjusted costs did not differ between cohorts for inpatient ($267; 95% CI, $1017-$1550; P = .68) or outpatient care ($2828; 95% CI, $311-$5966; P = .08).

Despite higher adjusted costs of outpatient testing potentially related to colonic and extracolonic findings among asymptomatic elderly patients 1 year after initial CTC compared to OC, we found no differences in adjusted total, inpatient, or outpatient costs between cohorts. Although Medicare does not cover screening CTC, our results suggest that these modalities generate comparable downstream costs to payers.