[1] Denver Hlth Med Ctr, Dept Med, Denver, CO USA
[2] Univ Colorado, Hlth Sci Ctr, Denver, CO USA
[3] Colorado Fdn Med Care, Aurora, CO USA
[4] Yale Univ, Sch Med, Dept Internal Med, New Haven, CT 06510 USA
[5] Yale Univ, Sch Med, Ctr Outcomes Res & Evaluat, Yale New Haven Hosp,Dept Internal Med, New Haven, CT USA
[6] Yale Univ, Sch Med, Ctr Outcomes Res & Evaluat, Yale New Haven Hosp,Dept Epidemiol & Publ Hlth, New Haven, CT USA