The Current Landscape of Atrial Fibrillation and Atrial Flutter Clinical Trials: A Report of 348 Studies Registered With ClinicalTrials.gov.

Objectives: This analysis sought to systematically characterize trial-level patterns in atrial fibrillation/atrial flutter (AF/AFL) by using the ClinicalTrials.gov database.

Background: Despite an abundance of clinical trials in this field, there is a lack of high-level evidence guiding management of AF/AFL.

Methods: We queried all closed, phase II to IV interventional trials registered in the ClinicalTrials.gov database through October 2016 that enrolled patients known to have AF/AFL. Published trials were evaluated for methodological quality, using the 3-item Jadad scale (range: 0 to 5, where 5 = highest quality).

Results: The initial search yielded 465 uniquely registered studies, of which 348 directly studied AF/AFL. Of those studies, 173 (50%) were published, enrolling a median of 190 patients from a median of 15 sites. The volume of published trials increased over time (7% prior to 2008 vs. 41% from 2014 to 2016; p < 0.001 for trend). Of the completed trials, 29% remain unpublished. Industry sources accounted for most funding (54%). Recurrence of AF/AFL was the most common endpoint (45%), whereas rates of primary clinical endpoints were low (13%). The mean Jadad score of published trials of pharmacological approaches (n = 112) was 4.0 ± 1.4. Of the 61 AF/AFL trials involving ablation or device therapies, 69% were randomized, 28% were single-arm studies, and patient, proceduralist, and event-ascertainment blinding was used in 16%, 4%, and 44%, respectively.

Conclusions: Contemporary trials of AF/AFL are often multicenter and modest in size. The primary study endpoint is commonly recurrence of arrhythmia, even in high-quality and late-phase trials. Although methodological quality is high in trials of pharmacologic approaches, trials of AF/AFL ablation and device therapies variably employ randomization and blinding.