Warfarin persistence among atrial fibrillation patients - why is treatment ended?

Warfarin treatment discontinuation is significant among patients with atrial fibrillation (AF). Studies mainly focused on whether the proportion of warfarin persistence and discontinuation are clinically appropriate are absent. This study evaluates warfarin persistence with focus on predictors for, and reasons to, warfarin discontinuation in AF patients.

From the national quality register AuriculA, all AF patients in Sundsvall, Sweden, on warfarin treatment on January 1, 2010 were included. These 478 patients were followed until discontinuation or study-stop, December 31, 2013. By going through each patient's medical record, risk factors for thromboembolism, bleeding, and causes of discontinuation were obtained.

Proportion of warfarin persistence was 0.91 (95% confidence interval [CI] 0.89-0.93) after 1 year and 0.73 (95% CI: 0.69-0.77) after 4 years. Previous intracranial bleeding, excessive alcohol use, anemia, and pulmonary or peripheral emboli were each associated with over two times higher risk of discontinuation (hazard ratio [HR] 5.66, CI 2.23-14.36; HR 2.54, CI 1.48-4.37; HR 2.40, CI 1.38-4.17; and HR 2.13, CI 1.02-4.46). Among patients discontinuing, 50.5% were due to questionable causes, such as sinus rhythm (33.9%), patients demand (10.1%), and falls (8.2%). The majority (43.1%) of treatment discontinuers were changed to aspirin, while 40.4% of them were left without medical stroke prophylaxis.

Although persistence to warfarin among AF patients proves higher than previously reported, there is room for improvement since half of the discontinuers have questionable reasons for treatment stop and the majority of them receive no other efficient stroke prophylaxis.