Patients with type 2 diabetes who have poor glycemic control and a certain genetic variation have an increased risk of coronary artery disease, according to a study in the November 26 issue of JAMA, the Journal of the American Medical Association.
Among the known risk factors for cardiovascular disease, diabetes mellitus ranks as one of the most potent. It increases the lifetime risk of a major cardiac event by 2 to 4 times, relative to individuals without diabetes, according to background information in the article. A substantial proportion of cardiovascular risk is under the control of genetic factors.
Genetic variation on chromosome 9p21 has been associated with increased risk of coronary artery disease (CAD) in the general population. Alessandro Doria, M.D., Ph.D., M.P.H., of the Joslin Diabetes Center, Harvard Medical School, Boston, and colleagues examined the association of this genetic variant with coronary artery disease in individuals with type 2 diabetes and whether the association is affected by poor glycemic control. The researchers conducted two studies, with one including 734 type 2 diabetes patients (322 with angiographically diagnosed CAD and 412 with no evidence of CAD), who were recruited between 2001 and 2006; the other study included 475 type 2 diabetes patients whose survival status was monitored from their recruitment between 1993 and 1996 until December 31, 2004.
Participants for both studies were tested for a representative single-nucleotide polymorphism (gene variation) of chromosome 9p21 (rs2383206) and characterized for their long-term glycemic control by averaging measurements of hemoglobin A1c (HbA1c) taken in the years before study entry.