Assessing the uptake of the core outcome set in randomized controlled trials for coronary artery disease: a trial registry analysis

Background: Coronary artery disease (CAD) is a global health crisis, responsible for nearly 20 million deaths annually worldwide and 12.6% of all deaths in the United States. Randomized controlled trials (RCTs) are critical for developing evidence-based clinical guidelines, but inconsistent outcome reporting across RCTs hinders evidence synthesis and comparability. In 2015, McNamara et al. introduced a CAD core outcome set (COS) to promote standardization in CAD trial outcomes. This study evaluates the uptake of the CAD COS in RCTs registered at ClinicalTrials.gov since its publication. Methods: This trial registry analysis evaluated the uptake of the CAD COS in phase III/IV RCTs registered on ClinicalTrials.gov from May 2010 to June 2023. Trials were included if they assessed CAD interventions and excluded if the trials were non-randomized, focused on diagnostic tests, or were categorized as “not applicable” (e.g., behavioral interventions). COS adherence was measured as the proportion of reported outcomes among the 23 defined in the CAD COS. We analyzed changes in adherence over time, including pre- and post-COS publication periods, with secondary analyses examining continent, sponsor type, recruitment status, and enrollment number. Results: Among 433 trials, procedural interventions (45.0%) and all-cause mortality (40.9%) were the most reported outcomes, while acute renal failure (2.1%) and dyspnea (2.8%) were the least. Pre-2015, trials reported an average of 11.5% of the COS-defined outcomes. Post-2015, trials initiated after the CAD COS publication reported a slightly higher proportion of COS-defined outcomes compared to earlier trials, reflecting a modest increase in the number of items reported. However, this increase was not statistically significant (p = 0.012). Recruitment status significantly influenced adherence (p < 0.001), while continent and sponsor type did not. A weak positive correlation was observed between enrollment number and adherence (r = 0.27, p < 0.001). Conclusions: Despite its publication in 2015, CAD COS uptake remains limited, with no significant changes in adherence over time. Barriers such as limited dissemination, lack of trialist awareness, and preferences for custom outcomes likely contribute to these findings. Greater emphasis on education, patient-centered outcomes, and COS tailored to specific CAD indications is needed to enhance uptake and comparability in CAD trials.