CHAPTER 2.1 28 in the HF trial participants compared to trial-eligible registry patients, as high up to 30% even after adjustment for prognostic factors. From a drug developer and/or regulatory perspective, prognostic enrichment strategies were advocated and used in many cardiovascular trials to identify patients who a have higher likelihood of cardiovascular events.32 Additionally, excluding patients with other comorbidities in these trials could lead to lower competing risks of death from non-cardiovascular causes. On a broadly similar note, trial-eligible registry patients selected for the PARADIGM-HF trial criteria had higher risk of both cardiovascular and noncardiovascular mortality compared to non-eligible registry patients.41 From the clinicians’ perspective, it is important to be aware that half of patients were ineligible, and that even among trial-eligible patients, residual differences between cardiovascular and non-cardiovascular outcomes persists. Strengths and limitations The strength of this study lies in the large sample sizes from both trial and observational datasets. Direct access to individual patient data also enabled the reporting of case-mix-adjusted differences in outcomes between trials and registry. There are also several limitations to this study. First, we applied a harmonised set of criteria which were common across the trials based only on data that were also available from the registries. There was not sufficient depth in the data from the registries to assess many of the eligibility criteria such as worsening HF in the past 12 months, scheduled coronary revascularisation within 3 months or severe valve disease. Also, not all criteria per RCT have been considered but only the most common ones. For these reasons, the percentage of patients eligible for trial inclusion is likely overestimated. The trials included in this study were a convenient sample based on data accessibility; thus, it can be difficult to infer these findings to other HF trials. Secondly, a large proportion of trials patients came from two RCTs which excluded patients with atrial fibrillation (BEAUTIFUL and SHIFT), which might have impacted the results. However, we believe that this impact is not substantial, as supported by sensitivity analyses (Supplementary figures 1 and 2). Although the trials evaluated here were not the most recent HFrEF trials, we do not expect large changes in patient and clinical characteristics among those enrolled in trials then and now. This is supported by a baseline characteristics comparison with DAPA-HF and PARADIGM-HF, which showed comparable patient characteristics in terms of mean
RkJQdWJsaXNoZXIy MjY0ODMw