1. Kaiser Permanente Division of Research, Oakland, California
2. Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California
3. Center for Clinical Management Research, VA Ann Arbor Health System, Ann Arbor, Michigan
4. Division of Pulmonary and Critical Care, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
5. Primary Care and Outcomes Research, Stanford University, Stanford, California