A review published in 2015 found a reduction of atrial fibrillation in people undergoing heart surgery if they were given statins before surgery. However, the review was withdrawn in 2016 when questions were raised about some of the included studies. To accompany the publication of the updated review, a Cochrane Library editorial, titled Preoperative statins in cardiac surgery: a tale of small study bias or ‘the truth, and nothing but the truth’, takes a closer look at how the authors handled study registration.

Statins, initially hailed for their potential to reduce cardiovascular risks, have been a topic of debate in the context of cardiac surgery. A recently updated Cochrane review, led by Marques Antunes and colleagues, scrutinised randomised controlled trials (RCTs) that compared statin therapy with placebo in the perioperative period of elective cardiac surgery. The review included eight RCTs involving 5,592 participants, following stringent criteria to exclude studies that did not have proof of ethics approval or did not have a pre-registered protocol.

The findings indicate that statin use in the perioperative period offers little to no difference in outcomes such as atrial fibrillation, postoperative short-term mortality, myocardial infarction, stroke, renal failure, and length of hospital stay. This comprehensive analysis challenges earlier suggestions of significant benefits from smaller, less robust studies.

Rui Providencia’s editorial underscores the critical role of methodological rigor in clinical research and the ongoing challenges posed by small study effects and potentially problematic clinical trials. Cochrane's efforts to exclude unreliable studies and focus on high-quality RCTs are highlighted as essential steps toward reliable evidence synthesis.

"The potential role of statins in patients undergoing cardiac surgery has been a matter of debate over recent years. In this editorial, we go through the important aspects raised by the authors of the recent Cochrane systematic review focusing on the topic."

- Rui Providencia 

The editorial and systematic review collectively underscore the need for cautious interpretation of past findings and the importance of ongoing research to establish clear clinical guidelines.

Read the Cochrane Library editorial in Farsi.