1. Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
2. Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
3. Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
4. Division of Nephrology, Department of Internal Medicine, Tufts Medical Center, Boston, Massachusetts