Patients hospitalized with acute renal failure who require hemodialysis have mortality rates exceeding 50 percent in most studies. Studies from the 1980s examining the frequency of hemodialysis in acute renal failure showed better control of blood urea nitrogen (BUN) and fewer sepsis episodes with daily dialysis sessions, but no overall mortality benefit.

Schiffl and colleagues report on a nonrandomized study of daily hemodialysis versus conventional every-other-day dialysis in patients with acute renal failure. The investigators enrolled 160 patients from a university hospital's intensive care units who were alternately assigned to daily or every-other-day dialysis. Patients who were deemed sick enough to need continuous hemofiltration were not included in the study. The only specific criteria mentioned that merited continuous treatment were hepatorenal syndrome and cardiogenic shock. Fourteen patients were withdrawn from the study, mostly because of clinical deterioration or need for surgery.

Daily hemodialysis provided better control of BUN (mean value of 60 mg per dL) than conventional dialysis (104 mg per dL), and was associated with smaller fluid shifts (1.2 L ultrafiltration volume versus 3.5 L). Fewer hypotensive episodes occurred (5 percent of dialysis sessions versus 25 percent) and fewer cases of sepsis (22 versus 46 percent). The overall mortality rate was lower in the daily dialysis group (28 versus 46 percent for conventional treatment). Renal function returned more rapidly, on average, for daily dialysis patients (mean of nine days, versus 16 days for every-other-day dialysis).

In an accompanying editorial, Bonventre points out the nonrandomized treatment assignment and the lower overall mortality than most previous studies of acute renal failure, implying that those enrolled in this study were less severely ill. He notes that the mean BUN of greater than 100 in the conventional dialysis group might indicate an insufficient duration for the every-other-day dialysis sessions, rather than superior control as a result of daily hemodialysis.

The authors conclude that daily hemodialysis was associated with better metabolic control, fewer complications, and lower mortality compared with conventional every-other-day dialysis for acute renal failure.