inclusion criteria: - age 18 or greater - signed informed consent - end-stage renal disease (esrd) who receive hemodialysis 2 or more times each week and are expected to continue on dialysis indefinitely.

inclusion criteria: - age 18 or greater - signed informed consent - end-stage renal disease (esrd) who receive hemodialysis 2 or more times each week and are expected to continue on dialysis indefinitely.

inclusion criteria: - age 60 or greater - signed informed consent - end-stage renal disease (esrd) who receive hemodialysis 2 or more times each week and are expected to continue on dialysis indefinitely.

inclusion criteria: - age 60 or greater - signed informed consent - end-stage renal disease (esrd) who receive hemodialysis 2 or more times each week and are expected to continue on dialysis indefinitely.