ObjectiveAcute renal failure can be treated with continuous renal replacement therapy (CRRT) or intermittent hemodialysis. There is no difference in mortality, although patients treated with CRRT may have a higher rate of renal recovery. Given these considerations, an estimate of the costs by modality may help in choosing the method of dialysis. As such, the objective of this study was to estimate the cost of CRRT and intermittent hemodialysis in the intensive care unit and to explore the impact of renal recovery on subsequent clinical outcomes and costs among survivors.DesignRetrospective cohort study of all patients who developed acute renal failure and required dialysis between April 1, 1996, and March 31, 1999.SettingTwo tertiary care intensive care units in Calgary, Canada.PatientsA total of 261 critically ill patients.InterventionsNone.MeasurementsAll patients were followed to determine in-hospital and subsequent clinical outcomes (survival and frequency of renal recovery). The immediate and potential long-term costs of CRRT and intermittent hemodialysis were measured.Main ResultsThe cost of performing CRRT ranged from Can $3,486 to Can $5,117 per week, depending on the modality and the anticoagulant used, and it was significantly more expensive than intermittent hemodialysis (Can $1,342 per week). Survivors with renal recovery spent significantly fewer days in hospital (11.3 vs. 22.5 days,p< .001) and incurred less healthcare costs ($11,192 vs. $73,273,p< .001) over the year after hospital discharge compared with survivors who remained on dialysis.ConclusionsImmediate cost savings could be achieved by increasing the use of intermittent hemodialysis rather than CRRT for patients with acute renal failure in the intensive care unit. Because of the high cost of ongoing dialysis, CRRT may still be an economically efficient treatment if it improves renal recovery among survivors; further study in this area is required.