KP Index at the Initiation of Dialysis for Patients with End-stage Renal Disease

BACKGROUND The time at which renal replacement therapy (RRT) is initiated in patients with end-stage renal disease (ESRD) has a great influence on the prognosis of the patient; however, there are currently no accurate guidelines for the initiation of RRT. Traditionally, nephrologists usually initiate RRT on the basis of the observation of the uremic symptoms and changes in the laboratory parameters, such as the serum creatinine concentration and/or glomerular filtration rate (GFR). DOQI guidelines suggest a weekly Kt/Vurea < 2.0 or an nPNA < 0.8 g/kg/day as objective indices for the initiation of dialysis. Thus, a KP index was formulated (weekly Kt/Vurea+2.5 x nPNA) x 1/2 using the above two clinically useful and objective indices to determine the adequate time to initiate RRT in patients with ESRD. METHODS Of 186 patients admitted to the renal unit of Soonchunhyang Bucheon hospital, those with ESRD and a weekly Kt/Vurea below 3.0 were selected. The patients with a weekly Kt/Vurea index between 1.0 and 2.0 were classified into one of two groups; KP index > 2.0 and KP index < 2.0. The groups were compared and analyzed in relation to their renal function, biochemical indices and the numbers of patients per group starting RRT. Further, the correlations between the KP and other indices were analyzed in all the patients. The patients were then further divided into another two groups according to their weekly Kt/Vurea and KP index: group one; between 1.5 and 2.0 and group 2; between 2.0 and 2.5. The numbers of patients per group starting RRT were compared. RESULTS The KP index < 2.0 group showed significantly lower indices for weekly Kt/Vurea, nPNA and %LBM (%) than those of the KP index > 2.0 group, while there were no significant differences between the groups in the serum albumin concentration, serum creatinine concentration, FFEFBM and RRF. Also, there was a statistically significant higher rate of incidence of patients starting RRT in the KP index < 2.0 group than in the KP index > 2.0 group. There was a significant correlation between the KP and other indices in all patients. When comparing the number of patients starting RRT, the weekly Kt/Vurea index demonstrated no significant differences between the 1.5 < weekly Kt/Vurea < 2.0 and 2.0 < weekly Kt/Vurea < 2.5 groups, but the number of patients starting RRT in the 1.5 < KP index < 2.0 group was significantly higher than that in the 2.0 < KP index < 2.5 group. CONCLUSION The KP index is considered a clinically useful index in ESRD patients for determining an appropriate time for the initiation of RRT. Also, the timing of the initiation of RRT should be fixed with regard to the various other indices and clinical features for a desirable prognosis of the patients. In addition, further studies will be required to determine accurate guidelines for an appropriate time for RRT initiation.