Enrolment criteria for diabetes cardiovascular outcome trials do not inform on generalizability to clinical practice: The case of glucagon-like peptide-1 receptor agonists

Aim: To evaluate the generalizability of cardiovascular outcome trials (CVOTs) on glucagon-like peptide-1 receptor agonists (GLP-1RAs), we assessed what proportion of real-world patients with type 2 diabetes (T2D) constitute true CVOT-like populations. Materials and Methods: We applied inclusion/exclusion (I/E) criteria of each GLP-1RA CVOT to a cross-sectional database of 281 380 T2D patients from Italian diabetes outpatient clinics. We calculated the proportion of patients eligible for each CVOT and compared their clinical characteristics with those of trial patients. In addition, we used a Bayesian network-based method to sample the greatest subsets of real-world patients yielding true CVOT-like populations. Results: Between 98 725 and 124 164 T2D patients could be evaluated for CVOT eligibility. After excluding patients who were already on GLP-1RAs and applying I/E criteria, 35.8% of patients would be eligible for REWIND, 34.1% for PIONEER-6, 13.4% for EXSCEL, 10.1% for SUSTAIN-6, 9.5% for HARMONY and 9.4% for LEADER. Overall, 45.4% of patients could be eligible for at least one of the CVOTs. These patients, however, were extremely different to trial patients in most of the clinical characteristics, including demographics, concomitant medications and complications. The greatest CVOT-like subsets of real-world patients were 0.5% for SUSTAIN-6, 1.0% for EXSCEL, 1.2% for LEADER, 1.8% for PIONEER-6 and 7.9% for REWIND. Conclusions: A very small proportion of real-world patients constitute true CVOT-like populations. These findings question whether any meaningful information can be drawn from applying trial enrolment criteria to real-world T2D patients.