[1] Univ Texas, Sch Med, Ctr Clin Res & Evidence Based Med, Div Gen Med, Houston, TX 77030 USA
[2] Univ Texas, Sch Med, Dept Med, Houston, TX 77030 USA
[3] Houston VA Med Ctr, Houston Ctr Qual Care & Utilizat Studies, Hlth Serv Res & Dev Ctr Excellence, Houston, TX USA
[4] Baylor Coll Med, Sect Hlth Serv Res, Houston, TX 77030 USA