BARCELONA – Adults with diabetes mellitus are at increased risk of subsequent new-onset atrial fibrillation – and the younger the age at diabetes onset, the greater the likelihood of developing the arrhythmia.
That’s the key finding from a Danish national registry study in which all 5,168,416 Danish adults without atrial fibrillation in 1996 were followed through 2012 for development of atrial fibrillation (AF). The study population included 75,197 Danes with diabetes at baseline and another 235,327 who developed the disease during follow-up, Dr. Jannik L. Pallisgaard explained at the annual congress of the European Society of Cardiology.
Dr. Jannik L. Pallisgaard
During follow-up, 5.6% of those with diabetes and 3.3% of those without diabetes developed AF. The mean time from diabetes onset to AF onset was 5 years, reported Dr. Pallisgaard of the University of Copenhagen.
"What was particularly interesting, I think, is that we found the youngest patients were the group at highest risk" of developing AF, he said. "We suggest that starting at the onset of diabetes, routine pulse palpation, ECGs, and focused patient interviews asking about any signs of atrial fibrillation could prove beneficial in detecting the arrhythmia."
The incidence rate ratio for developing AF per 1,000 person-years of follow-up was roughly 2.5-fold greater in 18- to 39-year-olds with diabetes than in their nondiabetic peers. From this peak rate in young adults, the magnitude of relative risk dropped in stepwise fashion with age: The variability in risk was lower in 40- to 60-year-old diabetics than in the 18- to 39-year olds and lower still in 65- to 74-year olds. Variability in the incidence rate ratio finally bottomed out at a still statistically significant 1.3-fold increased risk of developing AF in diabetic individuals ages 75 and older compared to their nondiabetic peers.
Dr. Pallisgaard noted that while the relative risk of developing AF was greatest in the 18- to 39-year-olds, the absolute number of new cases of AF was far greater in older patients because there were so many more of them with diabetes. He cautioned that as the obesity epidemic leads to more and more patients developing type 2 diabetes at younger ages, more cases of AF can be expected in young adults.
Dr. Pallisgaard cited two likely mechanisms underlying the observed increased risk of AF in diabetic patients: left ventricular hypertrophy and vascular inflammation, which are both often present in the diabetic population.
He reported having no financial conflicts regarding this study, conducted with Danish institutional research funds.