LOS ANGELES — Long-term ACE inhibitor therapy was associated with a 21% decreased risk of colorectal cancer in a cohort of hypertensive patients over age 50, Dr. George Makar reported at the annual Digestive Disease Week.
“The benefit of ACE inhibitors is most pronounced with 5 years of exposure,” said Dr. Makar, of the gastroenterology division, University of Pennsylvania School of Medicine, Philadelphia. The protective effect was greater (75%) in people with diabetes than in nondiabetics, he noted.
Dr. Makar and his colleagues conducted a nested, case-control cohort study of hypertensive patients older than 50 years, some of whom were receiving long-term ACE inhibitor therapy. Using the General Practice Research Database (United Kingdom), they identified 1,988 subjects with a new diagnosis of colorectal cancer; each case was matched to up to 10 controls (total of 18,131) based on age, sex, calendar year, and duration of follow-up. Patients were excluded if they developed colorectal cancer within 1 year of their diagnosis of hypertension or if cases had received ACE inhibitor therapy before their cancer diagnosis for less than 1 year.
ACE inhibitor therapy of more than 3 years' duration was associated with a significant reduction in colorectal cancer risk (OR 0.79); the analysis was adjusted for duration of hypertension follow-up and number of physician visits within 1 year of the index trial visit. The investigators found a significant duration-response effect among patients with diabetes (adjusted OR 0.27). There was no significant difference between users and nonusers of aspirin or NSAIDs.
Limitations of the study included incomplete data on obesity and tobacco exposure. Also, no data were collected on potential confounders such as family history and use of over-the-counter NSAIDs and dietary supplements.