Colonoscopy reduced CRC mortality rates among veterans

CHICAGO — Researchers at Digestive Disease Week reported undergoing colonoscopy resulted in significant reductions in colorectal cancer mortality rates among veterans, particularly in left-sided cancer, according to data presented.

“There are few data regarding the effect of colonoscopy on colorectal cancer outcomes,” Charles J. Kahi, MD, from the Indiana University School of Medicine, said in a presentation. “From the VA’s perspective, and beyond, this has indications from different levels. From the individual perspective, veterans differ from the general population into a different set of risk factors: older, more males, high prevalence of smoking. And they have higher [incidence of] colorectal cancer than the normal prevalence. From the systems perspective, the VA is more centralized and less reliant on financial incentives for individual providers, and thus may provide a better benchmark for other health care settings.”

Using the national VA Medicare administrative data, the researchers analyzed 7,363 veterans diagnosed with CRC between Jan. 1, 2003, and Dec. 31. 2008, and with CRC-related mortality by Dec. 31, 2010. Mean patient age was 73.3 years and 98.8% were men.

Additionally, 29,452 comparative control cases were identified. CRC was either right-sided (n = 2,993), left-sided (n = 3,965), unknown (n = 335) or synchronous in both sides (n = 70).

Patients with CRC, compared with the controls, had a greater mean Charlson comorbidity score (2.75 vs. 1.51; P < .0001) and had a higher prevalence of diabetes (46.9% vs. 40.9%; P < .0001), chronic obstructive pulmonary disease (47.2% vs. 41.6%; P < .0001), ever-use of aspirin (44.5% vs. 32.8%; P < .0001) and ever-use of non-aspirin NSAIDs (44.3% vs. 36.7%; P < .0001).

The veteran patients with CRC were significantly less likely compared with control patients to have undergone colonoscopy (OR = 0.47; 95% CI, 0.44-0.5). Colonoscopy reduced risk of mortality in both patients with left-sided cancer (adjusted OR = 0.34; 95% CI, 0.31-0.38) and patients with right-sided cancer (aOR = 0.66; 95% CI, 0.59-0.73).

Kahi advised that covariate information such as BMI and physical activity were missing in the data they retrieved, and information on family history was often limited. Surrogate data, such as COPD in lieu of cigarette smoking, were used in certain cases.

“Colonoscopy in this VA study was associated with about 50% overall colorectal cancer mortality reduction and the reduction was significant on both sides of the colon,” Kahi concluded. “Understanding the reasons for the colonoscopy effectiveness is critical ... and it underscores the importance of ongoing quality measurement and improvement interventions.” – by Talitha Bennett

References:

Kahi CJ, et al. Abstract 84. Presented at: Digestive Disease Week; May 6-9, 2017; Chicago.

Disclosure : Kahi reports no relevant financial disclosures.