The quantitative evaluation of online haemodiafiltration effect on skin hyperpigmentation.

BACKGROUND Skin pigmentation is a common problem for dialysis patients, but little is known about the factor responsible for the colour intensity. Middle-molecular-weight (MMW) substances have been suggested to be responsible for the skin colour. Several papers have reported that β(2)-microglobulin (β(2)-MG) correlates with the skin colour, and haemodiafiltration (HDF) is effective to reduce the skin hyperpigmentation. However, a quantitative skin colour follow-up on patients treated with online haemodiafiltration (online HDF) has not been performed. METHODS Sixty-one patients were enrolled in this study. Quantification of skin colour was done using a reflected light colorimeter. Among them, 51 patients were under haemodialysis (HD), and the other 10 patients were under online HDF. Follow-ups to estimate the skin colour change were performed for 6 months. Among 10 patients under online HDF, four patients were also investigated by crossover way between HD and online HDF. RESULTS Compared with controls, patients treated with HD had darker skin. The colour value was well correlated with age, haematocrit, sex, diabetes and β(2)-MG but not with Kt/V. The skin colour got worse under HD treatment as well as the values of β(2)-MG, but online HDF improved the hyperpigmentation and the β(2)-MG values. CONCLUSIONS Our data show the effectiveness of online HDF on skin colour and suggest that HD patients' skin colour can be improved by modality change.