1 Prehospital and Emergency Research Centre , Health Services and Systems Research, Duke-NUS Medical School, Singapore, Singapore; Department of Emergency Medicine, Singapore General Hospital, Singapore, Singapore.
2 Department of Family Medicine and Community Health, Durham, NC, USA; Department of Population Health Sciences, Durham, NC, USA; Duke University School of Medicine, Durham, NC, USA; Health Services and Systems Research, Duke-NUS Medical School, Singapore, Singapore. Electronic address: audrey.blewer@duke.edu.