Journal Club Summary
Methodology Score: 4/5
Usefulness Score: 2/5
Question and Methods: This multicenter, randomized, open-label, non-inferiority trial compared delayed vs early cardioversion for emergency department patients with recent-onset, symptomatic atrial fibrillation.
Findings: Sinus rhythm at four weeks was present for 91% of patients in the delayed cardioversion group and 94% of patients in the early cardioversion group (p=0.005 for non-inferiority).
Limitations: This study was not powered to assess safety, but cardiovascular complications were rare in both groups.
Interpretation: Rate control with delayed cardioversion may be an acceptable alternative to early cardioversion when managing patients with paroxysmal atrial fibrillation.
By: Dr. Bo Zheng
Epi Lesson Non-inferiority Trials
Most RCTs aim to determine whether one intervention is superior to another (superiority trials). Often a non-significant test of superiority is wrongly interpreted as proof of no difference between the two treatments (in fact the intervention may be inferior to the standard therapy offered). Non-inferiority trials are distinct from superiority trials such that they are designed to determine whether a given intervention is non-inferior by a pre-specified margin compared to a control. This pre-specified margin is critical. It should be well described, justified and reasonable. The critical reader will ask themselves if they feel this margin is truly clinically significant. Analyses should follow a per-protocol analytical approach, such that patients are analyzed only when the treatment was as planned. Otherwise, if you have cross overs, this dilutes the chances of finding a difference between the treatment arms and may lead you to erroneously determining that the new treatment is non-inferior to the standard, only because many patients in the new treatment arm received the standard treatment.
By: Dr. Jeff Perry