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

BACKGROUND: Chronic Kidney Disease-associated pruritus (CKD-aP) is common in dialysis patients, associated with lower quality of life and increased risk of death. We investigated the association between residual eGFR, dialysis adequacy or serum phosphate level and CKD-aP in incident dialysis patients.METHODS: 1256 incident hemodialysis (HD) and 670 peritoneal dialysis (PD) patients (>18y) from the Netherlands Cooperative Study on the Adequacy of Dialysis study were included (1997-2007) and followed until death, transplantation, or max 10y. CKD-aP was measured using a single item of the KDQOL-36. The associations were studied by logistic and linear regression analyses, adjusted for potential baseline confounders.RESULTS: At baseline mean (SD) age was 60 (16), 62% were men and median (IQR) residual eGFR was 3.4 (1.7-5.3) ml/min/1.73m2. 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/1.73m2 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:-0.17;-0.51) and -0.45 (95%CI:-0.19;-0.71), 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.