1 Cancer Research And Biostatistics, Seattle, WA, United States; University of Washington-Harborview Center for Prehospital Emergency Care, Departments of Emergency Medicine and Medicine, University of Washington, Seattle, WA, United States.
2 Cancer Research And Biostatistics, Seattle, WA, United States; University of Washington-Harborview Center for Prehospital Emergency Care, Departments of Emergency Medicine and Medicine, University of Washington, Seattle, WA, United States. Electronic address: nichol@uw.edu.