Dialysis dose has been established as a determinant of morbidity and mortality in chronic hemodialysis patients. To identify remediable barriers to the delivery of adequate hemodialysis, we examined factors that affected adherence to prescribed dialysis dose. End-Stage Renal Disease (ESRD) Network 4 facilities that fell into the lowest quintile in measures of dialysis adequacy were studied. At the time of this study, Network 4 was composed of 178 dialysis facilities in Delaware and Pennsylvania. Those 29 facilities had an average delivered urea reduction ratio (URR) of <0.67 and/or 71% of patients with a URR of 0.65. (The mean URR value of Network 4 was 0.699 with a compliance ratio of 80%.) Dialysis treatment sheets were reviewed for all patients in the 29 facilities for all treatments during a calendar week. Predialysis and postdialysis blood urea nitrogen (BUN) values from 1 treatment during this week were used to calculate URR and Kt/V. A total of 1,339 patients with a mean age of 61.9 <plus/minus> 15.1 years and a mean duration of ESRD of 3.4 +/- 3.3 years were dialyzed in the 29 units. Mean prescribed duration of dialysis (T) was 219 +/- 26 min. with a mean blood flow rate (BFR) of 393 +/- 62 mL/min. Concordance between the prescribed and delivered T (-5 min), DFP (-50 mL/min), and hemodialyzer were assessed, by patient, for each treatment (Tx). Characteristics of a delivered Kt/V 4 < 1.2 were duration <4 hours, BFR < 350 mL/min, patient weight > 100 kg, and delivered BFR 50 mL/min less than prescribed BFR. Multivariate analysis of the relationship between delivered dose of dialysis and patients and treatment characteristics identified black race, male gender, and younger age as demographic factors associated with low delivered dose. potential remediable barriers identified by this analysis included reduced treatment time (>10%) and use of catheters for angioaccess. These data suggest components of the dialysis process that might be targeted in future quality improvement projects to improve the adequacy of dialysis delivery. (C) 2000 by the National Kidney Foundation, Inc.