Risk factors for the development of atrial fibrillation on ibrutinib treatment.

Ibrutinib increases the risk of atrial fibrillation (AF), but the associated risk factors are not clearly defined. We performed retrospective review of ibrutinib-treated patients in a large academic practice to identify risk factors for new-onset AF. Variables with values <.05 in logrank analysis were included as pairs in two-variable Cox regression. Of the 168 patients treated with ibrutinib, 60.7% had chronic lymphocytic leukemia/small lymphocytic lymphoma and 39.3% other histologies. The incidence of AF was 11.9% after a median 154-day ibrutinib exposure. Only heart failure (hazard ratio, 95% confidence interval; 14.1, 5.3-37.2) and left atrial abnormality on electrocardiogram (5.4, 1.9-15.4) were independently significant in paired Cox regression. Eighty-seven percent of patients with HF satisfied Framingham clinical criteria. As structural heart disease is a strong risk factor for incident AF, we emphasize the importance of baseline electrocardiogram, recommend baseline clinical screening for HF and, in specific instances, a baseline echocardiogram.