[1] VA Palo Alto Hlth Econ Resource Ctr, Menlo Pk, CA 94025 USA
[2] Stanford Univ, Dept Hlth Res & Policy, Palo Alto, CA 94304 USA
[3] Eastern Colorado Hlth Care Syst, Dept Vet Affairs, Denver, CO USA
[4] Northport VA Med Ctr, Northport, NY USA
[5] Univ Colorado, Sch Med, Dept Surg, Aurora, CO USA
[6] Vet Affairs Med Ctr, Coordinating Ctr, Cooperat Studies Program, Perry Point, MD USA