1 Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
2 Westmead Research Centre for Evaluation of Surgical Outcomes, Department of Surgery, Westmead Hospital, Sydney, New South Wales, Australia.
3 General Practice/Family Medicine, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
4 Research, Education, Development & Innovation, Primary Health Care, Region Västra Götaland, Sweden.
5 Primary Health Care Clinic for Homeless People, Gothenburg, Sweden.
6 College of Medicine & Dentistry, James Cook University, Cairns, Queensland, Australia.
7 Gold Coast University Hospital, Southport, Queensland, Australia.