Lessons from the hemodialysis (HEMO) study: An improved measure of the actual hemodialysis dose

The Hemodialysis (HEMO) Study is a multicenter, prospective, randomized, 2 x 2 factorial clinical trial designed to evaluate the efficacy of the dose of dialysis delivered ("standard" v "high") and dialysis membrane flux ("lo w" v "high") in reducing the morbidity and mortality of patients. The study is nearly half complete. Although both patients and investigators are blin ded to the overall findings, which will not be available for another 3 year s, important data have been generated from which a more accurate expression has been derived for the dose of dialysis received by each patient in the trial. This new expression of the effectiveness of dialysis, eKt/V, is a tw o-pool approximation derived from the traditional single-pool Kt/V (spKt/V) and time on dialysis. The dialysis prescription for the HEMO Study subject s is individualized to achieve the target dose for each patient and is clos ely monitored by measuring the more accurate and validated expression of eK t/V. Comparisons of the HEMO Study dose of dialysis with other studies have been confused by this unique expression (eKt/V) of the dialysis dose and a dequacy adopted for the HEMO Study. The target eKt/V dose in the "standard" arm of the Study Is 1.05 and in the "high" arm is 1.45 per dialysis thrice weekly. Based on data available from 426 subjects randomized to each arm, the target of 1.05 in the "standard" dose of the HEMO Study is equivalent t o an spKt/V of 1.32, and that of the "high" dose, 1.67. Thus, volunteers in the "standard" arm of the Study are receiving a tightly controlled and clo sely monitored dose, which is above the current national mean spKt/V, and a bove that of the accepted minimum standard spKt/V of 1.2. When completed, t he HEMO Study will show whether there are merits of a tightly controlled he modialysis dose that is consistently delivered over a prolonged period and whether a high dose Is beneficial and safe to prescribe. (C) 1999 by the Na tional Kidney Foundation, Inc.