Julian Bion1, Elie Azoulay2. 1. Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Queen Elizabeth Hospital, Birmingham, UK. j.f.bion@bham.ac.uk. 2. Medical Intensive Care Unit, AP-HP, Saint-Louis Hospital ECSTRA team, Biostatistics and Clinical Epidemiology, UMR 1153 (Center of Epidemiology and Biostatistic Sorbonne Paris Cité, CRESS), INSERM, Paris Diderot Sorbonne University, Paris, France.