380 Risk of Bias Assessment among Randomized Controlled Trials Referenced in the 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: A Cross-Sectional Review

Abstract

Randomized controlled trials (RCTs) provide the most reliable evidence of the impact of medical intervention, however bias can invalidate the results of RCTs. This study aimed to identify the risk of bias of randomized controlled trials (RCTs) referenced in the 2015 American Heart Association (AHA) guidelines update for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC). All RCTs cited as references in the 2015 AHA guidelines update for CPR and ECC were extracted. After excluding non-human trials, crossover studies, cluster trials, etc, 2 reviewers assessed the risk of bias among RCTs included in this study. The Cochrane Collaboration’s tool for assessing the risk of bias in 6 domains (random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, and selective reporting) was used. A total of 166 RCTs were selected for analyses. Of these, 72.9% (121/166) had a high risk of bias for blinding of participants and personnel. Although a small proportion of the trials was at high risk of bias in the remaining 5 domains, 33.7% (56/166) had an unclear risk of bias for random sequence generation, and 45.2% (75/166) had an unclear risk of bias for blinding of outcome assessment. Additionally, among 5 domains of risk of bias excluding random sequence generation, the proportion of trials at unclear or high risk of bias in journals with a relatively high IF (≥5 and <10) and high IF (≥10) was lower than that in journals with a low IF (<5) The proportion of trials at unclear or high risk of bias was high in the 2015 AHA guidelines for CPR and ECC, especially for random sequence generation and blinding of participants/outcome assessment. This tendency was more prominent in journals with a low IF (<5). Risk of bias should be considered when interpreting and applying the CPR guidelines in the clinical setting.