Effect of residual kidney function and dialysis adequacy on chronic pruritus in dialysis patients

Abstract

Background: Chronic kidney disease-associated pruritus (CKD-aP) is common in dialysis patients, and is associated with lower quality of life and increased risk of death. We investigated the association between residual estimated glomerular filtration rate (eGFR), dialysis adequacy or serum phosphate level and CKD-aP in incident dialysis patients.

Methods: A total of 1256 incident hemodialysis (HD) and 670 peritoneal dialysis (PD) patients (>18 years) from the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) study were included (1997-2007) and followed until death, transplantation or a maximum of 10 years. CKD-aP was measured using a single item of the Kidney Disease Quality of Life Instrument-36. The associations were studied by logistic and linear regression analyses, adjusted for potential baseline confounders.

Results: At baseline mean (standard deviation) age was 60 (16) years, 62% were men and median (interquartile range) residual eGFR was 3.4 (1.7; 5.3) mL/min/1.73 m2. The prevalence of CKD-aP (∼70%) was similar in HD and PD. It was observed that 12 months after starting dialysis (after multivariable adjustment) each 1 mL/min/1.73 m2 higher residual eGFR, one unit higher total weekly Kt/V, or 1 mmol/L lower serum phosphate level was associated with lower burden of CKD-aP in HD and PD patients of -0.05 (95% CI -0.09; -0.02) and -0.09 (95% CI -0.13; -0.05), -0.15 (95% CI -0.26; -0.05) and -0.35 (95% CI -0.54; -0.16), and of -0.34 (95%CI: -0.51; -0.17) and -0.45 (95%CI: -0.71; -0.19), respectively. We found no association between dialysis Kt/V and CKD-aP.

Conclusions: Higher residual eGFR and lower serum phosphate level, but not the dialysis dose, were related with lower burden of CKD-aP in dialysis patients.

Keywords: dialysis; dialysis adequacy; itching; pruritus; residual kidney function.

Graphical Abstract

Figure 1:

Burden of pruritus (measured on a 5-point Likert scale) over time in HD and PD patients. Mean scores ±SD of pruritus are represented by the solid lines, over a period of 10 years. Blue lines represents HD patients, orange lines PD patients. Due to the long follow-up time, the number of patients contributing data differs across the time points in the graphs, see table attached. For HD and PD, median (IQR) and mean (±SD) eGFR are shown.

Figure 2:

Linear mixed models analyses for the association between residual eGFR (A), dialysis Kt/V (B), total weekly Kt/V (including residual kidney function) (C) and pruritus over 10 year follow-up among HD patients.

Figure 3:

Linear mixed models analyses for the association between residual eGFR (A), dialysis Kt/V (B), total weekly Kt/V (including residual kidney function) (C) and pruritus over 10 year follow-up among PD patients.