A Systematic Review of Contemporary Randomized Trials in Cardiothoracic Surgery

Background: This analysis was conducted to characterize contemporary randomized controlled trials (RCTs) in cardiothoracic surgery. Methods: We selected randomized controlled trials published in the journals with the highest impact factor in medicine, general surgery, and cardiothoracic surgery and published between 2008 and 2020. Trial characteristics as well as measures of reporting and quality were summarized and compared. Results: Ninety-three trials were included; 44 (47.3%) were prospectively registered and 14 (31.8%) had a discrepancy between the registered and published primary outcome. Most trials (n = 83 [89.1%]) used a superiority design, a composite primary outcome (n = 82 [88.2%]), and a major clinical event as the primary end point (n = 67 [72.0%]). Blinding was used infrequently, and most trials did not control for surgeon experience (n = 74 [79.5%]) or monitor the intervention (n = 90 [96.7%]). Twenty-four (25.8%) trials had high risk of bias. Twenty-one (27.3%) trials were funded by industry. A median 1.62% of patients (interquartile range, 0.00-3.70) crossed over between trial arms. Most trials reported a favorable outcome (n = 53 [58.9%]). For eligible trials, the median fragility index was 2.0 (interquartile range, 0.0-4.0), meaning the change of 2 patient outcomes would render the significant result insignificant. Spin, or distortion in reporting, was identified in 9 of 53 trials (17.0%). The median number of citations was 25 (10-56). Conclusions: Contemporary trials in cardiothoracic surgery are pragmatic with low rates of loss to follow-up and crossover. Few trials implemented measures to ensure quality of the intervention, and the presence of spin was infrequent.