Coronary and Colorectal Disease May Be Comorbid

HONG KONG, Sept. 25 -- What's bad for the heart may also be bad for the colon, according to investigators here.

Patients newly diagnosed with coronary artery disease here had nearly twice the rate of colorectal polyps or other neoplasms than those free of heart disease, reported Annie On On Chan, M.D., Ph.D., of the University of Hong Kong, and colleagues in the Sept. 26 issue of the Journal of the American Medical Association.

The association between coronary disease and colorectal growths was even stronger if patients smoked or had metabolic syndrome.

The researchers said that the growth of colorectal polyps and the development of coronary stenoses share similar risk factors, such as diabetes, smoking, hyperlipidemia, sedentary lifestyle, high-fat and low-fiber diet, obesity, and hypertension.

Furthermore, metabolic syndrome -- diabetes or impaired glucose tolerance, hypertriglyceridemia, low HDL cholesterol, central obesity, and hypertension -- includes most of the risk factors for both colon polyps and coronary artery disease.

In a cross-sectional study, 414 patients were recruited for screening colonoscopy after undergoing coronary angiography from November 2004 through June 2006.

Coronary disease found in 206 patients was defined as at least a 50% diameter stenosis in any one of the major coronary arteries. The other 208 patients were designated as coronary disease-negative.

An age- and sex-matched control group of 207 individuals was also recruited from the general population.

Patients were excluded for use of aspirin or statins, personal history of colorectal disease, or colonoscopy in the past 10 years.

The rate of colorectal neoplasm in the coronary-disease-positive group was 34%, in the coronary disease -negative 18.8%, and general population group 20.8% (P

In contrast, only one malignancy (0.5%) was detected in the coronary-disease -negative group and three (1.4%) in the general population group. All were asymptomatic, small, and early.

Both colorectal neoplasm and coronary artery disease probably develop through chronic inflammation, now recognized as being pivotal in the pathogenesis of atherosclerosis and thus coronary artery disease, the researchers said.

The design of the current study might have a potential bias, Dr. Chan and colleagues said, in that they assessed only the rate of colorectal neoplasm in patients with coronary artery disease who had an angiogram. However, they said, there might be a considerable percentage of patients in the general population with heart disease who have not had an angiogram.

The predictive value, they added, of the metabolic syndrome and smoking on the positive association of colorectal neoplasm and coronary artery disease is limited by the nature of the cross-sectional study. A prospective study for this finding is desirable, they said.