Monitoring dialysis efficacy by comparing delivered and predicted Kt/V

Introduction. In Europe, especially in Germany, little is currently known a bout the relationship between delivered and predicted haemodialysis doses f or patients on maintenance haemodialysis. We compared delivered and predict ed Kt/V in patients of an outpatient dialysis centre in Berlin by calculati ng the ratio of delivered and predicted Kt/V, resulting in the efficacy quo tient, Q(E) Moreover, we studied the influence of technical and anthropomet ric parameters on both delivered Kt/V and Q(E) under routine clinical condi tions. Methods. Blood samples were taken after the long interval in a thrice-weekl y regimen before and 10 min after ultrafiltration and 100 ml/min slow-pump method. Delivered Kt/V was computed using the Daugirdas III formula. Predic ted Kt/V was estimated from the dialysis filter urea clearance given by the manufacturer, treatment time and the total body water (V) computed by the Watson formula and was corrected for real blood flow. As and when appropria te, bivariate and multivariate regression analyses were used to make compar isons. Results. The mean quotient (Q(E)) between delivered and predicted Kt/V was 1.02+/-0.20. Mean delivered Kt/V in 377 treatments of 128 patients was 1.28 +/-0.27. Delivered Kt/V and Q(E) were positively associated (P<0.001). Q(E) was significantly associated with post-HD urea, body mass index (BMI) and sex, but not with session time. Significant positive predictors for deliver ed Kt/V were post-dialysis urea, sex, session time, blood flow and kind of vascular access. BMI was inversely related to delivered Kt/V. Discussion. In this study, the relationship between delivered and predicted Kt/V (QE) was reproducible and close to the ideal value of 1.0. In contras t to delivered Kt/V, Q(E) was not influenced by session time, and positivel y by BMI. Since Q(E) gives a valid measure of technical dialysis efficacy w e suggest the use of this parameter in addition to delivered Kt/V to monito r HD adequacy in clinical routine more comprehensively.