Study assesses impact of diabetes mellitus on cardiac geometry

A study of U.S. Hispanics with diabetes mellitus showed a link between impaired glucose regulation and adverse measures of cardiac function and structure. Researchers at Columbia University's Mailman School of Public Health in collaboration with colleagues from Wake Forest Medical School and six other institutions extended previous knowledge regarding the concept of 'diabetic cardiomyopathy, by also observing that these relationships emerged early and before the full onset of diabetes mellitus. The findings are published online in the journal Circulation: Cardiovascular Imaging.

This is the first study to assess the impact of diabetes mellitus on cardiac geometry using several measures and the first to report the association between insulin resistance and cardiac structure and function among a U.S. sample population of Hispanic/Latinos not previously studied.

"Our findings inform and extend the clinical concept of diabetic cardiomyopathy -- adverse changes in cardiac structure and function commonly observed among patients with diabetes mellitus in two ways," said lead author Ryan Demmer, PhD, assistant professor of Epidemiology at the Mailman School of Public Health. "First, they confirm that diabetes mellitus -- both controlled and uncontrolled -- is related to the worse measures of cardiac structure and function among Hispanics. Second, they demonstrate that these relationships emerge early in the natural history of diabetogenesis and prior to diabetes development."

Results were from the ECHO-SOL (Echocardiographic Study of U.S. Latinos) which examined chronic disease risk factors and related morbidity and mortality of 1,818 Hispanic/Latino men (43 percent) and women (57 percent) 45 years of age and older. Participants were recruited from the Bronx, New York; Chicago; Miami; and San Diego.

Glucose intolerance was defined as having a prediabetes hemoglobin of 5.7 and <6.5 percent; diabetes mellitus was defined as a fasting glucose reading of 126 mg/dL, and a hemoglobin of 6.5 percent. Prediabetes was prevalent for 42 percent of the participants, and diabetes mellitus was reported by 28 percent with 47 percent uncontrolled and a hemoglobin of 7.0 percent.

"Whether aggressive glucose-lowering therapy can prevent these cardiac alterations that lead to heart failure remains unknown, but it supports the notion that HbA1c <7% may be important for cardiac health," said Dr. Carlos J. Rodriguez, senior author and PI of the ECHO-SOL.

These findings also raise the possibility that primary prevention efforts targeting insulin resistance and glucose homeostasis might also be beneficial for optimal cardiac health and heart failure prevention although future studies are necessary. "If confirmed, these results would have high public health importance given the fact that Hispanics have elevated rates of Type 2 diabetes compared to the U.S. population overall. This is coupled with the fact that Hispanics are expected to account for 25 percent of the U.S. population by 2050," noted Demmer.