Department of Anaesthesia, Aberdeen Royal Infirmary, NHS Grampian, Aberdeen AB25 2ZN, UK; Pain and Opioids after Surgery (PANDOS), European Society of Anaesthesiology and Intensive Care (ESAIC) Research Group, Aberdeen, UK; Epidemiology Group, Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK; University Hospital Nîmes, Nîmes, France.