High-Frequency Hemodialysis

Hundreds of thousands of people with end-stage renal failure are alive today because they receive treatment with hemodialysis. Although kidney transplantation and peritoneal dialysis also are available to treat kidney failure, in-center hemodialysis remains the predominant form of renal replacement therapy in North America. Despite its dramatic success at saving lives, hemodialysis is far from perfect therapy: More than 20% of hemodialysis patients die each year (1). Even more troubling, the annual mortality rate has changed little in the past decade, despite some success in achieving evidence-based quality improvements (2–4). In addition, morbidity remains high, with frequent complications of heart disease, hypertension, anemia, bone disease, poor nutrition, inflammation, depression, and impaired cognitive and physical function. These result in impaired quality of life and contribute to diminished longevity. Observational studies (5,6) suggest that many of these adverse outcomes may be caused in part by inadequate dosage of dialysis. The Hemodialysis (HEMO) study was designed to test the hypothesis that a higher dosage of dialysis would enhance dialysis-related survival. This 2 × 2 factorial design, randomized clinical trial (RCT) compared outcomes of patients who were treated with eKt/V for urea of 1.45 with those with eKt/V for urea of 1.05, and high-flux versus low-flux dialysis (7). The results of this study were a surprise to many: There were no significant differences between the two dosage groups in mortality, hospitalizations, or other secondary end points. However, negative results from the HEMO trial do not rule out benefits of more intensive therapies that extend beyond the limits of conventional thrice-weekly hemodialysis. The “dosage of dialysis” in determining outcomes may involve more than urea removal. The removal of phosphate (8) and larger molecules may be important in determining outcomes. Longer treatment times are associated with prolonged survival (9,10), an …