Glomerular Filtration Rate >= mL/min (according to Modification of Diet in Renal Disease [MDRD] formula or Cockroft & Gault formula) Glomerular filtration rate (GFR) >= ml/min/. m^ according to the Modified Diet in Renal Disease (MDRD) abbreviated formula Glomerular filtration rate (GFR) ? mL/min/. m according to the modified diet in renal disease (MDRD) abbreviated formula FULL STUDY INCLUSION CRITERIA: Glomerular filtration rate (GFR) >= mL/min/. m^ according to the Modification of Diet in Renal Disease (MDRD) abbreviated formula Glomerular filtration rate (GFR) ? mL/min/. m according to the Modification of Diet in Renal Disease (MDRD) formula. Glomerular filtration rate (GFR) >= ml/min/. m^ according to the Modified Diet in Renal Disease (MDRD) abbreviated formula Glomerular filtration rate (GFR) must be greater than or equal to mL/min/. m according to the Modified Diet in Renal Disease (MDRD) abbreviated formula. Glomerular filtration rate (GFR) ? mL/min/. m according to the Modified Diet in Renal Disease (MDRD) abbreviated formula. Glomerular filtration rate (GFR) >= ml/min/. m^ according to the MDRD (modified diet in renal disease) abbreviated formula Glomerular filtration rate > ml/min/. m according to the Modified Diet in Renal Disease abbreviated formula or creatinine clearance (CrCL) > ml/min (Cockcroft and Gault) Glomerular filtration rate>/= mL/min/. m according to the Modified Diet in Renal Disease abbreviated formula Glomerular Filtration Rate ? mL/min (according to Modification of the Diet in Renal Disease (MDRD) formula or cockroft & Gault formula)