1. Department of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 8, 413 45 Göteborg, Sweden
2. Department of Surgery, The Sahlgrenska Academy, University of Gothenburg, SE-413 45 Göteborg, Sweden
3. Department of Health Care, Regional Secretariat, Västra Götaland Region, SE-405 44 Göteborg, Sweden