Methodological quality and risk of bias assessment of cardiovascular disease research : analysis of randomized controlled trials published in 2017

Abstract

Background: All randomized-controlled trials (RCTs) are required to follow high methodological standards. In this study, we aimed to assess the methodological quality of published cardiovascular clinical research trials in a representative sample of RCTs published in 2017.

Methods: Cochrane Central Register of Controlled Trials was used to identify cardiovascular clinical research trials with adult participants published in 2017. Overall, 250 (10%) RCTs were randomly selected from a total of 2,419 studies. Data on general trial characteristics were extracted and the risk of bias (RoB) was determined.

Results: Overall, 86% of RCTs have reported at least one statistically significant result, with the primary outcome significant in 69%, treatment favored in 55%, and adverse events reported in 68%. Less than one-third (29%) of trials were overall low RoB, while the other two-thirds were rated unclear (40%) or with high RoB (31%). Sequence generation, allocation concealment, and selective reporting were the domains most often rated with high RoB. Drug trials were more likely to have low RoB than non-drug trials. Significant differences were found in RoB for the allocation concealment and blinding of participants and personnel between industry-funded and non-industry-funded trials, with industry-funded trials more often rated at low RoB.

Conclusion: Almost two-thirds of RCTs in the field of cardiovascular disease (CVD) research, were at high or unclear RoB, indicating a need for more rigorous trial planning and conduct. Prospective trial registration is a factor predicting a lower risk of bias.