Researchers from the National Cancer Institute and the University of North Carolina have reported that the risk of complications from colonoscopy is increased in the very elderly and in those with certain chronic health conditions. The results of this study were published in the June 16, 2009 issue of the Annals of Internal Medicine.

Colon cancer is the second leading cause of cancer death in the United States. If detected and treated early, colorectal cancer is highly curable. Screening for colorectal cancer is recommended starting at the age of 50 for individuals at average risk of developing the disease and earlier for those at higher risk. Several screening tests are available, including the fecal occult blood test, sigmoidoscopy, double-contrast barium enema, optical colonoscopy, and CT colonography.

To explore the safety of colonoscopy and whether safety varies by the age and health of the patient, researchers evaluated information from 53,220 Medicare beneficiaries aged 66 to 95 who underwent colonoscopy between 2001 and 2005.

These researchers found that a serious gastrointestinal event (perforation or bleeding within 30 days of colonoscopy) occurred in 6.9 per 1,000 colonoscopies. Although this risk was low, it varied by age. The risk of a serious gastrointestinal event was more than twice as high among persons aged 85 and older than among persons between the ages of 66 and 69.

These results are consistent with recommendations from the U.S. Preventive Services Task Force (USPSTF). The USPSTF recommends against colorectal cancer screening among adults over the age of 85 because the risks are likely to outweigh the benefits.

In addition to varying by age, the risk of serious gastrointestinal events also varied by the health of the person being screened. People with a history of stroke, chronic obstructive pulmonary disease, atrial fibrillation, or congestive heart failure were more likely than people without these conditions to experience a serious gastrointestinal event following colonoscopy.

Comments: This study suggests that the overall risk of colonoscopy complications among Medicare beneficiaries is low. Nevertheless, risk increases with age and with certain chronic health problems. These observations suggest that some elderly or debilitated patients might have fewer complications from a CT colonography when the risks of perforation and bleeding are nonexistent.

Reference: Warren JL, Klabunde CN, Mariotto AB et al. Adverse events after outpatient colonoscopy in the Medicare population. Annals of Internal Medicine. 2009;150:849-857.