Evaluation of the adequacy of hemodialysis using ktv and other related indicies

Abstract EN

Background & Objection The index (Kt/V urea) is by far the most commonly used marker for adequacy of dialysis.

The aim of this study is to assess different mathematical equations for the direct calculation of Kt/V, and to find the relation between Kt/V and other indices (URR and creatinine clearance).

In addition, it also aims to compare urea kinetic modeling in two groups of hemodialysis (HD) patients with two different intervals of predialysis plasma creatinine concentrations.

Methods : Adequacy of HD was assessed in 50 chronic renal failure (CRF) patients (31 males and 19 females) aged 8-62 years on a regular thrice-weekly dialysis regimen in the Mosul Dialysis Center at Ibn Sina Teaching Hospital over a period of 6 months.

Blood samples were collected both predialysis and 30 minutes following the end of the dialysis session.

Plasma urea was measured and BUN was estimated both pre and postdialysis, while plasma creatinine was measured predialysis only.

Creatinine clearance was predicted for each patient using the Cockroft- Gault formula.

Results: Adequacy of HD was assessed using ten mathematical equations.

A statistically significant difference was revealed in the mean Kt/V values of these equations (P<0.0001).

The patients were divided into two subgroups according to predialysis plasma creatinine.

Those with plasma creatinine>8.75 mg/dl exhibited significantly higher mean Kt/V and mean URR values than those with predialysis plasma creatinine of < 8.75 mg/dl, with lower mean creatinine clearance.

A highly significant positive correlation was revealed between Kt/V and URR in the total sample of cases (r= 0.95, P<0.0001) and in the two subgroups (P<0.0001 for both).

Cockroft-Gault estimated creatinine clearance was not significantly correlated with Kt/V either in all cases, or in the two subgroups (P>0.05).

Predicted creatinine clearance, however, was significantly and inversely correlated with URR only in the total sample (r= -0.50, P <0.0001).

The duration that CRF patients were onHD was not significantly correlated with Kt/V either in all cases or in the sub grouping (P>0.05 in all).

Conclusions: It is clearly shown that there is an extreme difference in the Kt/V values using different available equations and it is certainly the time for agreement about the proper choice of the best method to calculate this parameter.Percent urea reduction ratio is significantly correlated with Kt/V and may be used as a substitute for Kt/V in the assessment of HD adequacy.

The nutritional status in HD patients should be properly assessed, as adequate treatment is obtained when blood urea is maintained within acceptable ranges in the presence of sufficient dietary intake.