For patients with diabetes, the risk of atrial fibrillation (AF) may be 40 percent greater, and even higher for patients who have been diagnosed with diabetes for long periods of time and who have uncontrolled glycemic levels, according to a study published in the April 22 issue of the Journal of General Internal Medicine.
“In the U.S., 25.4 million people are projected to have diabetes by 2011, rising to 37.7 million by 2031," the authors wrote. "Physiologic changes associated with diabetes include increased left atrial size and elevated C-reactive protein, a marker of chronic inflammation. Both findings are associated with heightened risk of atrial fibrillation, a common and serious arrhythmia that confers significant risks for stroke and death.”
Sascha Dublin, MD, PhD, of the Group Health Research Institute in Seattle, and colleagues investigated the association of diabetes mellitus and atrial fibrillation in 1,410 patients with newly found AF.
“When a patient with diabetes has symptoms like heart palpitations, clinicians should have a higher level of suspicion that the reason could be atrial fibrillation,” the authors wrote.
During the study, Dublin and colleagues compared the 1,410 Group Health patients with AF to 2,203 patients without AF who were selected on the basis of age, sex, and hypertension and calendar year.
According to the authors, the study adjusted for weight of patients because of the fact that both diabetes and AF are more common in the heavier patient population. Of the patient arm with AF, 252 of the 1,410 patients had pharmacologically treated diabetes versus 311 of patients who did not exhibit signs of AF.
Dublin et al found that for each additional year of diagnosis of the comorbidity the risk of developing AF increased by 3 percent.
The study results also showed that for patients exhibiting levels of glycosylated hemoglobin (HBa1c) over 9 percent, the risk of AF was two times greater compared to patients without diabetes.
Additionally, the rates of AF in patients who exhibited well-controlled diabetes—HBa1c levels of 7 percent or less—were similar to those patients undiagnosed with diabetes.
AF is important to diagnose early because it is treatable by drugs such as warfarin and can help prevent incidence of stroke, Dublin noted.
“It is hard to establish which comes first—diabetes or atrial fibrillation,” Dublin wrote. “But our finding that the risk of AF is higher with longer time since patients started medications for diabetes and with higher blood glucose levels, is strongly suggestive that diabetes can cause AF.”
The study was funded through a Veteran’s Affairs Health Services Research and Development fellowship.