1. Renal Section, VA Pittsburgh Healthcare System and Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Room 7E123 (111F-U), VA Pittsburgh Healthcare System, University Drive Division, Pittsburgh, PA 15240, USA
2. Cooperative Studies Program Coordinating Center, VA Connecticut Healthcare System, West Haven, CT, USA
3. National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
4. Health Economics Resource Center, VA Palo Alto Health Care System, Menlo Park, CA, USA