Figure 1. Patient Flowchart of Study Enrollment and Follow-up.

Of the 2967 patients who met eligibility criteria, 2227 (75.1%) agreed to participate. The 4 participating study sites were the University of Michigan Medical Center and Veterans Affairs Ann Arbor Healthcare System, both in Ann Arbor, Michigan, and Ben Taub Hospital and the Michael E. DeBakey Veterans Affairs Medical Center, both in Houston, Texas.