The Hemodialysis (HEMO) Study was a multi-center, randomized clinical trial designed to test whether the mortality and morbidity of hemodialysis (HD) patients can be reduced by modifying the dialysis procedure for the removal of toxins from the blood. The study examined two factors, the dose of dialysis delivered and the size of the molecules removed, to determine the effect on the survival or morbidity among hemodialysis patients. A two-by-two factorial design was used to assign 1846 patients randomly to either a standard or high dose of dialysis and to either a dialyzer with a low-flux or high-flux membrane for dialysis three times a week. The primary outcome, death from any cause, was not significantly influenced by the dose or flux assignment. The relative risk of death was not significantly different in the high-dose group compared to the standard-dose group, or the high-flux group as compared with the low-flux group. The main secondary outcomes, including first hospitalization, did not differ significantly for either the dose groups or the flux groups. Patients undergoing hemodialysis three times a week appear to have no major benefit from either a higher dialysis dose than that recommended by current U.S. guidelines or from the use of a high-flux membrane.

The HEMO study investigated whether modifying the dose of dialysis delivered and the level of flux of the dialyzer membrane altered the mortality and morbidity of maintenance hemodialysis patients.

The primary outcome measure was death from any cause. The main secondary outcome measures were the rate of all hospitalizations not related to vascular access and three composite end points: the first hospitalization for cardiac causes or death from any cause, the first hospitalization for infection or death from any cause, and the first decline of more than 15 percent from base line in the serum albumin level or death from any cause.

The study enrolled patients 18 to 80 years of age who were undergoing in-center hemodialysis thrice weekly and had been undergoing hemodialysis for three or more months. Patients were excluded from randomization if their residual urea clearance exceeded 1.5 ml per minute per 35 liters of urea, if their serum albumin level was less than 2.6 g per deciliter, or if an equilibrated Kt/V of more than 1.30 was not achieved within 4.5 hours during two of three consecutive monitored dialysis sessions in which the high-dose goal was targeted. On the basis of the last criterion, very heavy patients were excluded.

For patients undergoing hemodialysis thrice weekly, a higher dialysis dose than that recommended by current U.S. guidelines or use of a high-flux membrane did not show a beneficial effect on survival or morbidity. The effect of dose or level of membrane flux varied among selected subgroups of patients.