A Core Outcome Set for Small Abdominal Aortic Aneurysms

Abstract Background It remains elusive which patients with an abdominal aortic aneurysm (AAA) will experience cardio-vascular disease progression. Current literature on small AAAs is characterized by heterogeneous and selective outcome reporting. A core outcome set (COS), a consensus-based list of outcomes that should be reported as a minimum in research on a specific disease, is therefore needed. This is espe-cially important for research using artificial intelligence (AI) techniques. The current study aimed to create a European COS for use in clinical and AI research on small AAAs. This COS will be used in the VASCUL-AID project, which aims to identify risk factors for cardiovascular disease progression in patients with small AAA using AI. Methods This COS was developed in line with Core Outcome Measures in Effectiveness Trials (COMET) initi-ative recommendations in three steps. First, a longlist of AAA outcomes was identified through a sys-tematic literature search and through focus groups with patients, their caregivers, and healthcare pro-fessionals. Second, a three-round European Delphi survey was conducted with patients and a wide range of healthcare professionals. Third, an expert consensus meeting with key opinion leaders (KOL), patients, and patient representatives was held to finalize the COS. Results The AAA longlist consisted of 91 outcomes; 73 outcomes identified from the systematic literature search and 18 patient-centred outcomes identified from the focus groups. A total of 257 participants (of which 104 were patients) participated in the Delphi study. Delphi round 3 was filled in by 221 (66.9%) participants. The highest-rated outcomes from the third Delphi round were included for dis-cussion in the expert consensus meeting, which was attended by 23 KOL, two patients and one patient representative. Ten core outcomes were chosen across six health domains, with AAA rupture, mortali-ty, health-related quality of life, clinical success, and graft infection attaining 100% consensus for inclusion in the COS. Conclusion This first COS for small AAAs consists of ten outcomes and should be implemented in all clinical and AI research on small AAA. Clinical perspective What is new? Current literature on small abdominal aortic aneurysms (AAA) is characterized by heterogene-ity and selective outcome reporting. A Core Outcome Set (COS) is an expert consensus-based list of outcomes that should be re-ported as a minimum in all clinical research on a specific disease. A COS for small AAA was created, consisting of ten outcomes across six health domains, which may also be applied in artificial intelligence (AI) research such as the VASCUL-AID project. What are the clinical implications? This COS for patients with small AAA may enhance uniformity across and reproducibility of clinical research. In addition to clinical research, this COS may also be applied in cardiovascular risk prediction models for small AAA patients and will be included as endpoints in the VASCUL-AID pre-diction models.