Increased 30-day mortality in very old ICU patients with COVID-19 compared to patients with respiratory failure without COVID-19.

"Declarations Conflicts of interestThe authors declare that they have no competing interests. Ethics approval and consent to participateThe primary competent ethics committee was the Ethics Committee of the University of Duesseldorf, Germany. Institutional research ethic board approval was obtained from each study site. Consent for publicationThe manuscript does not contain any individual person's data in any form. Conflicts of interest The authors declare that they have no competing interests."

"Funding This study was endorsed by the ESICM. Free support for running the electronic database and was granted from Aarhus University, Denmark. The support of the study in France by a grant from Fondation Assistance Publique-Hôpitaux de Paris pour la recherche is greatly appreciated. In Norway, the study was supported by a grant from the Health Region West. In addition, the study was supported by a grant from the European Open Science Cloud (EOSC). EOSCsecretariat.eu has received funding from the European Union’s Horizon Programme call H2020-INFRAEOSC-05-2018-2019, Grant agreement number 831644. This work was supported by the Forschungskommission of the Medical Faculty of the Heinrich-Heine-University Düsseldorf and No. 2020-21 to RRB for a Clinician Scientist Track. No (industry) sponsorship has been received for this investigator-initiated study."

"Participants included in this analysis were enrolled to one of two prospective observational studies of very old intensive care patients (VIP2 and COVIP) [, ]. Participating critical care units recruited consecutive admissions of patients over 80 years during a 6-month period in 2018–19 (VIP 2) for non-COVID patients and patients over 70 years with proven SARS-CoV-2 infection from March 2020 to January 2021 (COVIP). The studies were registered at clinicaltrials.gov (VIP2: NCT0337069; COVIP: NCT04321265). The European Society of Intensive Care Medicine (ESICM) endorsed both studies."