Dialysis adequacy and homocyst(e)ine concentrations in peritoneal dialysis patients

Abstract

Introduction. Determinants of hyperhomocysteinaemia in peritoneal dialysis patients have been recently reported but there is still conflicting data on the influence of dialysis adequacy on homocysteine (Hcy). Methods. We studied 46 consecutive new continuous ambulatory peritoneal dialysis (CAPD) patients to determine the variation of Hcy before and 1 and 6 months after dialysis. The variation in Hcy was analysed with respect to dialysis adequacy, factors known to influence its metabolism, and Hcy peritoneal clearance. Results. Hcy was 31.9 ± 9 μmol/l before dialysis. It was significantly higher before dialysis than 1 month after the onset of PD (31.9 ± 9 μmol/l vs 23.2 ± 6.9 μmol/l, P < 0.0005). Weekly PD Hcy clearance was 14.3 ± 5.41. There was no relationship between pre-dialysis Hcy and 1 month post-dialysis Hcy (r = 0.176, P = 0.15). There was a strong relationship between PD Hcy clearance and both PD creatinine clearance (r = 0.502, P < 0.005) and Kt/V (r = 0.42, P < 0.005). There was no relationship between Hcy and PD creatinine clearance (r = -0.221, P = 0.11). In contrast, the decrease in tHcy at 1 month was related to PD Hcy clearance (r = 0.487, P < 0.01), to PD creatinine clearance (r = 0.349, P < 0.02) and to Kt/V (r = 0.32, P < 0.02). Multivariate analysis confirmed the relationship between the decrease in Hcy and dialysis adequacy. Eleven patients (24%) experienced arteriosclerotic complications. Fasting Hcy concentrations in this population were significantly higher before and 1 month-post-dialysis than in patients without cardiovascular complications. Conclusions. We observed a significant and prolonged reduction in Hcy concentrations by peritoneal dialysis in end-stage renal disease patients. The decrease in Hcy concentration was positively related to dialysis adequacy. This study suggests the possibility that dialysis adequacy may influence arteriosclerotic outcomes through an Hcy-lowering effect.