1 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. Electronic address: ta409@cantab.ac.uk.
2 Department of Anaesthesia and Perioperative Medicine, West Suffolk Hospital, Bury St Edmunds, UK.
3 Royal Adelaide Hospital, Adelaide, SA, Australia; University of Adelaide, Adelaide, SA, Australia.
4 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.