One-Third Type 2 Diabetic Adults May Have Undetected Cardiovascular Disease: Study

The study reveals that many people with Type 2 diabetes who have not had a heart attack or a history of cardiovascular disease are at high risk for cardiovascular complications.

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One-third of Type 2 diabetic adults may have undiagnosed cardiovascular disease. In persons with Type 2 diabetes compared to those without Type 2 diabetes, elevated levels of two protein biomarkers that signify heart damage were linked to undiagnosed or symptomless cardiovascular disease. The findings of the study published in the Journal of the American Heart Association, an open access, peer-reviewed journal of the American Heart Association.

To detect heart damage and stress, tests for high-sensitivity cardiac troponin T and N-terminal pro-B-type natriuretic peptide are utilised. These exams are frequently used to identify heart failure and heart attacks. 

The risk of future heart failure, coronary heart disease, or mortality may be increased by mildly higher concentrations of these proteins in the blood, which may be an early indicator of changes in the structure and function of the heart.

"What we are seeing is that many people with Type 2 diabetes who have not had a heart attack or a history of cardiovascular disease are at high risk for cardiovascular complications," said study co-author Elizabeth Selvin, Ph.D., M.P.H., a professor of epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore. 

"When we look at the whole population of people diagnosed with Type 2 diabetes, about 27 million adults in the U.S., according to the CDC, some are at low risk and some are at high risk for cardiovascular disease, so the open question is "Who is most at risk?" These cardiac biomarkers give us a window into cardiovascular risk in people who otherwise might not be recognized as the highest risk."

Researchers analyzed health information and blood samples for more than 10,300 adults collected as part of the U.S. National Health and Nutrition Examination Survey from 1999 to 2004. The aim was to determine if the previously unrecognized cardiovascular disease with no symptoms could be determined by elevated levels of the cardiac protein biomarkers among people with and without Type 2 diabetes. Study participants had reported no history of cardiovascular disease when they enrolled in the study.

Using stored blood samples from all study participants, researchers measured levels of two cardiac biomarkers. Mortality statistics were collected from the National Death Index. After adjusting for age, race, income and cardiovascular risk factors, they assessed the associations among elevated troponin and N-terminal pro-B-type natriuretic peptides with risk of death from cardiovascular death or all causes.

"Cholesterol is often the factor that we target to reduce the risk of cardiovascular disease in people with Type 2 diabetes. However, Type 2 diabetes may have a direct effect on the heart not related to cholesterol levels. If Type 2 diabetes is directly causing damage to the small vessels in the heart unrelated to cholesterol plaque buildup, then cholesterol-lowering medications are not going to prevent cardiac damage," Selvin said. 

"Our research suggests that additional non-statin-related therapies are needed to lower the cardiovascular disease risk in people with Type 2 diabetes."

Much research has focused on studying how traditional risk factors such as high blood pressure and cholesterol impact cardiovascular health, however, new evidence suggests that screening for certain cardiac biomarkers should be added to routine assessment of traditional cardiovascular risk factors.

"The biomarkers analyzed in this study are very powerful in systematically categorizing patients based on their health status. Measuring biomarkers more routinely may help us focus on cardiovascular prevention therapies for people with Type 2 diabetes who are at higher risk," she added.