The Removal Index for Evaluation of Dialysis

Objectives To find an index of adequacy that takes into consideration the effect of the decreasing concentration of urea nitrogen in hemodialysis (HD) and can be used before treatments to quantitate the prescriptions with the same criterion for both HD and continuous ambulatory peritoneal dialysis (CAPD).Design The removal index was obtained through mathematical theories and then compared with the urea index (KT/V) values of the sample patients.Patients Thirty-two HD and 21 CAPD patients were included. All patients were dialyzed with optimal urea index values and had been stable for at least one year.Results The removal index in HD (ξHD) for each dialysis was 0.62±0.07, and the normalized removal index in CAPD (ξCAPD) was 0.59±0.11. There was no statistical significance. This result is consistent with the fact that no difference of morbidity or mortality exists between these two modalities.Conclusion After mathematical manipulation, the removal index in HD can be presented in the form of the urea reduction ratio, which is a retrospective measure to estimate the performance of hemodialysis. This study implies that the removal index is able to facilitate the prescriptions for adequate dialysis. The removal index can also be used to explain the reason why the urea index values are always larger in HD than in CAPD.