A systematic assessment of the characteristics of randomised controlled trials cited by acute coronary syndrome clinical practice guidelines

Abstract

Aims: The aim of this study was to describe the methodological features of the randomized controlled trials (RCTs) cited in American and European clinical practice guidelines (CPGs) for ST elevation myocardial infarction (STEMI) and non-ST elevation acute coronary syndrome (NSTE-ACS). Methods and results: Out of 2128 non-duplicated references cited in the 2013 and 2014 American College of Cardiology/American Heart Association and 2017 and 2020 European Society of Cardiology CPGs for STEMI and NSTE-ACS, we extracted data for 407 RCTs (19.1% of total references). The majority were multicenter studies (81.8%), evaluated pharmacological interventions (63.1%), had a 2-arm (82.6%), and superiority (90.4%) design. Most RCTs (60.2%) had an active comparator, and 46.2% were funded by industry. The median observed sample size was 1001 patients (84.2% of RCTs achieved ≥80% of the intended sample size). Most RCTs had a single primary outcome (90.9%), which was a composite in just over half (51.9%). Among the RCTs testing for superiority, 44.0% reported a P-value of ≥0.05 for the primary outcome and 61.9% observed a risk reduction of >15%. The observed treatment effect was lower-than-expected in 67.6% of RCTs, with 34.4% having at least a 20% lower-than-expected treatment effect. The calculated post hoc statistical power was ≥80% for 33.9% of cited RCTs. Conclusions: This analysis demonstrates that RCTs cited by CPGs can still have significant methodological issues and limitations, highlighting that a better understanding of the methodological aspects of RCTs is crucial in order to formulate recommendations relevant to clinical practice.