Continuous Mortality Risk Among Peritoneal Dialysis Patients

C onventional hemodialysis (CHD) administered thrice weekly for 3to 4-hour sessions and peritoneal dialysis (PD) are the 2 most commonly delivered dialysis modalities. Patients treated with CHD are subject to short periods of rapid fluid and solute removal accompanied by brisk electrolyte shifts followed by long intervals when these substances reaccumulate. In contrast, PD uses the patient’s peritoneal membrane to allow for continuous and gradual removal of fluid and uremic toxins. A typical CHD schedule results in 2 one-day intervals and 1 two-day interval between dialysis sessions. The 2-day interval usually occurs from Saturday through Sunday or Sunday through Monday. Among CHD recipients, the period immediately following the 2-day interdialytic interval (either Monday or Tuesday) has recently been associated with an increased risk of death compared with other days of the week. The increased mortality risk may be mediated via significant fluid gain and electrolyte disequilibrium that occurs during the 2-day hiatus from dialysis. Since PD occurs daily, we hypothesized that mortality rates should be stable across different days of the week among PD recipients compared with those receiving CHD.