[1] Oregon Hlth & Sci Univ, Dept Emergency Med, Ctr Policy & Res Emergency Med, 3181 SW Sam Jackson Pk Rd,CR 114, Portland, OR 97201 USA
[2] Oregon Hlth & Sci Univ, Sch Publ Hlth, Portland, OR 97201 USA
[3] Univ Washington, Dept Surg, Seattle, WA 98195 USA
[4] Oregon Hlth & Sci Univ, Dept Obstet & Gynecol, Portland, OR 97201 USA
[5] Oregon Hlth & Sci Univ, Dept Emergency Med, Ctr Hlth Syst Effectiveness, Portland, OR 97201 USA
[6] Oregon Hlth & Sci Univ, Dept Internal Med, Div Geriatr, Portland, OR 97201 USA