News Article
Atrioventricular Block Boosted in Patients With Diabetes
TORONTO (EGMN) - Patients with diabetes have an unexpected, increased risk of developing third-degree atrioventricular block, according to a review of almost 14 million people during 1992 and 2002.
Although the reason for this link is unknown, several possible complications of diabetes could potentially cause a cardiac conduction disorder, including autonomic neuropathy, abnormal glucose metabolism, subclinical coronary disease, and subclinical cardiomyopathy, Dr. M. Reza Movahed said at the 14th World Congress on Heart Disease.
The absolute number of patients with diabetes and third-degree atrioventricular (AV) block was low: 0.4%-0.5% of patients sampled, a rate too small to warrant routine screening of diabetes patients with a Holter monitor, said Dr. Movahed, director of coronary care at the University of Arizona, Tucson. But AV block should be considered a possible diagnosis in patients with diabetes who show other signs of a conduction defect, such as syncope of unknown origin, he said. In addition, future research should examine whether patients with diabetes also show an increased risk for other cardiac conduction defects.
His study used data collected by the Nationwide Inpatient Sample, which annually collects data on a random sample of hospitalized U.S. patients. Data were analyzed for patients hospitalized in 1992 and 2002. Studying both years, which were randomly selected and a decade apart, gave researchers a better sense of how the link between diabetes and heart block might change over time.
The 1992 database included about 6,195,000 patients, of whom 0.5% had both diabetes and third-degree heart block, also known as complete heart block. The prevalence of complete heart block among patients without diabetes was 0.2%. In a multivariate analysis that adjusted for age, heart failure, and coronary artery disease, patients with diabetes were 2.5-fold more likely to have complete heart block than were patients without diabetes, a statistically significant difference, reported Dr. Movahed at the congress, which was sponsored by the International Academy of Cardiology.
The 2002 database included more than 7,853,000 patients, and the prevalence of third-degree AV block was 0.4% in patients with diabetes and 0.2% in those without diabetes. A similar multivariate analysis showed a 50% increased risk of complete heart block in patients with diabetes, compared with those without diabetes, also a significant difference.
The findings do not prove a cause-and-effect relationship between diabetes and an increased risk of complete heart block, Dr. Movahed said, but the significantly increased risk during both years that were analyzed suggests that the link is more than coincidental.
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