[1] Univ Penn, Perelman Sch Med, Renal Electrolyte & Hypertens Div, Philadelphia, PA 19104 USA
[2] Univ Penn, Ctr Clin Epidemiol & Biostat, Perelman Sch Med, Philadelphia, PA 19104 USA
[3] Bristol Myers Squibb Co, Lawrenceville, NJ USA
[4] Hosp Univ Penn, Div Hosp Med, 3400 Spruce St, Philadelphia, PA 19104 USA
[5] Northwestern Univ, Feinberg Sch Med, Dept Prevent Med, Chicago, IL 60611 USA
[6] Univ Penn, Perelman Sch Med, Hosp Univ Penn, Div Cardiovasc Med, Philadelphia, PA 19104 USA