• The slope of GFR is the primary outcome;Primary outcomes regarding CVD will focus on clinical events indicative of ischemic heart disease, CHF, stroke, and peripheral vascular disease supplemented by radiographic evidence of progressive CVD [ Time Frame: 5 yrs ] [ Designated as safety issue: No ]
  

• 1.Onset of ESRD; 2.Significant loss of renal function; 3.Composite clinical outcome defined by the occurrence of either 50% decline, or 25 l/min/1.73 m2 decline in GFR from baseline, or onset of ESRD; 4. Slope of change in proteinuria over time. [ Time Frame: 5 yrs ] [ Designated as safety issue: No ]
  

Eligible men and women who consent will be enrolled in this observational study. Participants will remain under the care of their usual physicians. Questionnaires will be completed and tests will be conducted that will provide information about aspects of kidney and heart health status.

Participants are screened over the course of a brief visit during which informed consent is obtained, height and weight measured, blood drawn and a few forms are completed.

If eligible, a participant will return to the center for a more extensive visit. At the Baseline Visit the following will occur:

• eligibility is confirmed
• weight, height, waist and body water and fat content are measured by Bioelectrical Impedance Analysis (BIA)
• blood pressure and heart rate are recorded
• information about medical history and medication used recently
• blood draw (about ½ cup) for the following tests: CBC (Complete Blood Count), tests of metabolism, and several other heart and kidney tests
• blood pressure in the leg and arm calculated as the Ankle Brachial Index (ABI)
• Electrocardiogram (ECG)
• urine sample and collection of 24-hour urine sample for kidney function testing
• complete questionnaires about quality of life, diet, mood, thought processes and physical activity
• nail clipping

This visit takes about 4 hours. If selected, the Iothalamate GFR test will also be conducted during or shortly after this visit. This test is repeated at the second and fourth annual visits.

Participants will be contacted by telephone six months after the Baseline Visit to ask about recent medical events and medications.

Participants will be asked to return to the center for annual visits during which many but not all of the procedures described above will be conducted. In addition, an echocardiogram will be conducted during the first and fourth annual follow up visits.

Subcohort participants will have a cardiac CT/EBT test conducted during the first and fourth annual follow up visits.