In‐hospital cardiac arrest registries and aetiology of cardiac arrest

. We have previously demonstrated that adjustment for important characteristics significantly affect survival estimates. 16 Future investigations should consider adjusted estimates depending on the research question. To ensure a structured framework for comparing systems of care for cardiac arrest, international guidelines for uniform reporting exists. 18 In the latest version from 2019, aetiology is not included as a data element to ensure uniform reporting. This contrasts with the out-of-hospital cardiac Utstein template where presumed cause of arrest is included. 19 As the aetiology of arrest can differ substantially between patients with in-hospital and out-of-hospital cardiac arrest, reporting guidelines should consider including aetiology in future updates to allow comparisons between registries and to allow combination of data from different registries.