1. V.A. San Diego Health Services Research and Development and Department of Medicine, University of California San Diego, San Diego, California.
2. Division of Pulmonary and Critical Care Medicine, Medical College of Wisconsin, and Milwaukee Veterans Affairs Medical Center, Milwaukee, Wisconsin.
3. Center for Patient Care and Outcomes Research, Medical College of Wisconsin, Wisconsin.
4. Department of Health Policy and Management, Johns Hopkins School of Public Health, Baltimore, Maryland.