The impact of dialysis modality on skin hyperpigmentation in haemodialysis patients.

BACKGROUND Skin hyperpigmentation in end-stage renal disease (ESRD) patients has been attributed to the accumulation of middle-molecular-weight (MMW) substances. Although an MMW mechanism suggests that hyperpigmentation may be improved by high-flux haemodialysis (HF-HD) and haemodiafiltration (HDF), this possibility has not been explored. In the present study, we investigated the impact of different dialysis modalities on skin colour in HD patients. METHODS Eighty-two ESRD patients on HD were divided into low-flux HD (LF-HD), HF-HD and HDF groups. The melanin index (MI) and erythema index (EI) of the abdomen and the flexor side of the forearm (non-sun-exposed areas) and the forehead (sun-exposed area) were determined by using a narrow-band reflectance spectrophotometer at baseline and after 12 months. RESULTS Even though absolute values of baseline and follow-up MI and EI of the three sites were comparable among the three groups, forehead MI and EI were significantly decreased after 12 months in the HDF group (P < 0.05). In addition, the change in forehead MI was significantly greater in the HDF than in the LF-HD group (-1.0 +/- 2.4% versus 0.3 +/- 1.6%, P < 0.05). Moreover, beta(2)-microglobulin reduction rates were negatively correlated with both changes in forehead MI (P < 0.01) and EI (P < 0.05). CONCLUSIONS Skin colour of sun-exposed areas was signi- ficantly decreased in ESRD patients receiving HDF therapy, suggesting that enhanced removal of MMW substances by convection may prevent or reduce hyperpigmentation in HD patients.