Target quantity for twice-a-week hemodialysis: the EKR (equivalent renal urea clearance) approach

The targets of dialysis per session, in terms of Kt/V and URR are well established for thrice-a-week hemodialysis (HD). The target values of these parameters could not be applied for the patients undergoing twice-a-week HD, which is performed in several developing countries. The equivalent renal urea clearance EKR (EKR [mL/min) = G (mg/min)/TAC (mg/mL)], which measures urea clearance in a continuous fashion, has been used in comparing amount of dialysis among the different modalities. For any chronic dialysis regimens the target EKRc, which was normalized to urea volume of distribution of 40 L, would be above 13 mL/min. Therefore, there is no data available regarding Kt/V, URR, and EKRc for twice-a-week HD.

The EKRc of 26 Thai patients treated with twice-a-week high flux HD were measured monthly for 12 months. The Kt/V, URR, and serum albumin were also measured monthly.

Overall, the mean EKRc of 294 patient-month analysis was 11.68 +/- 0.16 mL/min. Monthly EKRc had a high correlation to Kt/V (r = 0.80) and URR (r = 0.82). When serum albumin was employed as a surrogate marker for treatment failure, ROC analysis revealed that EKRc above 13 mL/min had 90% and 100% probabilities to maintain monthly and 12-month serum albumin levels above 4 gm/dL, respectively. To obtain the target EKRc above 13 mL/min at 90 and 95% confidence, the values of Kt/V per session were 2.11 and 2.25, respectively while those of URR were 82.89 and 84.52%, respectively.

For twice-a-week HD, to have the EKRc level above 13 mL/min, at 95% confidence, the Kt/V should exceed 2.2 and the URR should exceed 85% per session.