Diabetes in writingNew analysis of the PREFER in AF registry has revealed that atrial fibrillation (AF) patients with insulin-requiring diabetes are at greater risk of suffering stroke or systemic embolism than those with non-insulin required diabetes or no diabetes at all.

While diabetes is a known risk factor for thromboembolic events, this finding sheds new light on the role of insulin in the clinical setting

The findings are based on subanalyses of the PREFER in AF registry, a study conducted to provide insights into the management of AF in Europe, following the introduction of non-vitamin K oral anticoagulants (NOACs). This is the first study of its kind to independently quantify the annual rates of AF-related thromboembolic events in patients with diabetes according to insulin treatment.

In a group of 1,288 diabetic AF patients enrolled in the PREFER in AF registry, those with insulin-requiring diabetes were found to have a greater than 2.5-fold increased risk of stroke or systemic embolism at one year compared to those with non-insulin requiring diabetes and no diabetes. This was the case irrespective of comorbidities and the type of anticoagulant treatment used. 

Interestingly, rates of stroke or systemic embolism were not observed to be different in patients with diabetes not receiving insulin – compared to those without diabetes, which suggests that insulin requiring diabetes may increase the thromboembolic risk in AF patients.

Dr Giuseppe Patti, from the Department of Cardiovascular Sciences, Campus Bio-Medico University of Rome, said: “In this analysis from the PREFER in AF registry, the sole presence of diabetes does not imply an increased thromboembolic risk in AF patients, but it is the condition of diabetes requiring insulin therapy that appears to be an independent factor affecting the occurrence of AF-related stroke or systemic embolism.

“This could have significant implications for clinical practice and additional studies are required to substantiate the findings.”

Of the diabetic population included in the PREFER in AF registry, 22.4% of people had insulin-requiring diabetes, and only 1.5% had Type 1 diabetes. In the overall population, the incidence of stroke or systemic embolism at one year was 2.0 per 100 patients/year.

Raffaele De Caterina, study author from University Cardiology Division at the "G. d'Annunzio" University, Chieti, Italy, said: “These results provide important insights into the additional risks associated with insulin therapy and have potential implications for the assessment of thromboembolic risk in this patient population. 

“It is important to identify AF patients with diabetes who are taking insulin, and ensuring that appropriate anticoagulation treatment is provided to mitigate additional risk.”

The findings were published in the Journal of the American College of Cardiology.