[1] Univ Penn, Philadelphia Vet Adm Med Ctr, Electrolyte & Hypertens Div, Philadelphia, PA 19104 USA
[2] Univ Penn, Dept Med, Philadelphia, PA 19104 USA
[3] Univ Penn, Dept Biostat & Epidemiol, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[4] Thomas Jefferson Univ, Philadelphia, PA 19107 USA
[5] Drexel Univ, Philadelphia, PA 19104 USA