Enhancing bleeding reporting in acute coronary syndrome clinical trials: a systematic review of the ABC guidelines adherence

Bleeding events in acute coronary syndromes (ACS) significantly affect patient outcomes, yet consistent reporting remains a challenge for clinicians. Although multiple standardized bleeding definitions exist, the Academic Bleeding Consensus (ABC) provides the only dedicated reporting guideline. This systematic review evaluates the adoption of the ABC guidelines and adherence to bleeding definition reporting in clinical research. We systematically searched Scopus, Web of Science, MEDLINE, EMBASE, and Cochrane Central for randomized clinical trials (RCTs) published between 2012 and 2025 involving adult patients with ACS. Of the 135 RCTs included in the quantitative analysis, none fully adhered to the ABC reporting guidelines. Most trials only partially reported elements in the red and green domains, with only two RCTs fully reporting the orange domain. The Bleeding Academic Research Consortium (BARC) definition was the most frequently used (73.3%), though its reporting was often incomplete (82.8%). Industry-funded RCTs (OR: 3.66; 95%CI: 1.55-2.90), those prioritizing patient-important outcomes (OR: 13.22; 95%CI: 1.72-101.27), and trials with bleeding outcome reporting according to definition (OR: 3.88; 95%CI 10.22) were more likely to fully report bleeding definitions. Conversely, RCTs using the BARC definition showed lower rates of complete reporting. The lack of adherence to the ABC guidelines highlights the need for a universally accepted reporting framework that integrates qualitative and quantitative bleeding characteristics. Such a guideline would enhance the interpretability of ACS interventions, supporting better patient-centered decision-making.