A new analysis of Medicare data has found that after adjusting for patient demographic factors, costs are pretty much the same in the year following an initial screening exam for colorectal cancer, regardless of whether CT colonography (CTC) or optical colonoscopy (OC) is used, according to a report in Academic Radiology.
The analysis of more than 17,000 individuals undergoing optical colonoscopy and nearly 600 undergoing CTC did initially reveal higher costs per patient in the year following CTC, compared with OC. However, the total costs per patient did not differ significantly after adjusting for various demographic and socioeconomic factors, wrote Dr. Hanna Zafar, from the Hospital of the University of Pennsylvania, and colleagues (Acad Radiol, April 15, 2015).
"What we found was interesting: There were higher costs for colonic and extracolonic follow-up for CTC [compared with] the OC cohort; however, when you looked at total costs in the year following either modality, there were actually no differences between the two groups," Zafar said in an interview with AuntMinnie.com.
CTC's history
Data spanning more than 20 years of CTC practice show it to be an accurate and safe alternative to optical colonoscopy for colorectal cancer screening -- one with the potential to screen more than half of the population at risk, due in part to the relative unpopularity of more invasive conventional colonoscopy, according to the authors. Of course, colon cancer screening rates today represent only a tiny fraction of that potential.
In 2009, the U.S. Centers for Medicare and Medicaid Services (CMS) denied routine coverage of CTC (also known as virtual colonoscopy) for its target population, asymptomatic individuals ages 50 and older. CMS justified its decision by citing, among other things, the paucity of data on CTC's safety and costs versus invasive colonoscopy -- "in particular, differences related to follow-up testing of colonic and extracolonic findings on CTC," Zafar and colleagues wrote. (The U.S. Preventive Services Task Force is reviewing CTC once again in 2015 as a potential Medicare-covered colorectal cancer screening test, following CMS' 2009 denial of coverage.)
The limitations of prior cost analyses included their failure to incorporate control groups of patients who received optical colonoscopy rather than CTC. Another limitation was that testing rates and cost estimates for the follow-up of colonic and extracolonic findings were limited to chart review.
"Those previous papers are helpful, but we're actually comparing CTC to OC," Zafar said.
The current retrospective study aimed to compare total, inpatient, and outpatient Medicare costs among asymptomatic elderly patients in the year following either an initial CTC or optical colonoscopy study between January 2007 and December 2008 -- the two years preceding the CMS decision about coverage for screening CTC. A secondary aim was to examine differences in costs attributable to testing that were "plausibly related" to colonic or extracolonic findings, because of the impact these findings have on CTC.
The researchers included asymptomatic Medicare patients 66 years or older: 531 had CTC and 17,593 received OC. They used claims to identify total, outpatient, and inpatient Medicare costs, as well as testing and costs possibly related to outpatient colonic and extracolonic follow-up.
Cost comparison
The results showed that CTC had higher costs per patient in the year following an initial exam, compared with optical colonoscopy. The unadjusted median total costs after the first exam were $2,264 for CTC and $1,500 for OC (p < 0.0001).
However, the researchers also found that a higher proportion of patients received high-cost care in the CTC cohort (22%) than in the optical colonoscopy cohort (16%). Patients in the CTC cohort were also more likely to be white, to be 75 years or older, and to carry a higher burden of comorbid diseases, among other factors, Zafar and colleagues wrote.
So they performed another analysis to adjust for important demographic and socioeconomic predictors. After these adjustments, the investigators found no statistically significant difference in total costs 12 months after either procedure.
| Adjusted costs after 1st exam, CTC vs. OC | |||
| Care setting | CTC | OC | p-value |
| Total costs | $16,355 | $14,289 | 0.280 |
| Inpatient | $3,117 | $2,850 | 0.680 |
| Outpatient | $20,646 | $17,818 | 0.80 |
The authors believe their study is the first to compare differences in overall costs one year following receipt of initial CTC or OC among asymptomatic Medicare patients.
Some might be less than thrilled to see mean costs of $14,000 or $16,000 for a year of follow-up to colon screening, Zafar acknowledged. But it's important to remember that total Medicare costs include everything -- from heart attacks to car accidents, broken hips, and office visits -- that Medicare paid for on behalf of the patient during the year following screening, regardless of any relation or lack thereof to colon screening.
"In some ways I know that people may not like it because it's a very simplistic approach -- to look at total costs," Zafar said. "But in some ways it's one of the cleanest ways to look at it. You're just taking all costs for all reasons and all comers."
The point is that downstream costs to Medicare are the same regardless of the screening modality used, she added.
The results could inform the future debate over which modality -- CTC or optical colonoscopy -- is most cost-effective, according to the authors.
Of course, Medicare doesn't cover screening CTC yet, but "our results suggest that these modalities are equivalent from a downstream cost perspective," the authors wrote. "These findings are of value to payors and policy-makers evaluating coverage of screening CTC."
