Serum levels of proANP and albumin are independent predictors of mortality in the high-risk patients (elderly and diabetics) treated by haemodialysis (HD) and continuous peritoneal dialysis in 4-year prospective observation

Sir, Recently, Locatelli and Vigano [1] discussed the significance of natriuretic peptides as the marker for mortality in ESRD patients. They referred to the results published by Paniagua et al. [2] who noticed in a large cohort of CAPD, AD and HD patients that the N-terminal fragment of B-type natriuretic peptide (NT-proBNP) was a predictor of death risk independently of fluid volume overload and dialysis modality. The independency from fluid overload is explained by the relation of NT-proBNP elevation to both fluid overload and myocardial damage. In context of this observation, we would like to present the results of an as yet unpublished study performed in 86 dialysis patients (46 on maintenance HD and 40 treated by CAPD). The clinical characteristics of the study group were the following: median age 73.5 years (41 females and 45 males), 71% diabetics, 59% elderly, 30% of patients with both risk factors, median time on dialysis before inclusion 17 months, and a median residual diuresis of 550 mL. There were no differences between HD and CAPD patients in these features. However, the distinctive elements between HD and CAPD subgroups were lower albumin concentration (P < 0.002) and higher cholesterol levels (P < 0.001) in CAPD patients. In addition, the following laboratory parameters were determined in all patients at the onset of the observation: plasma proANP (amino terminal 1–98 ANP fragment), NT-proBNP concentration, serum CRP and IL-6 values. In the prospective observation, 53 patients (62%) survived 20 months, and 27 patients 50 months (the last point of the observation). No effect of dialysis modality (HD vs. CAPD) on the survival was discerned. In the univariate linear model, the survival was significantly associated with elevated CRP (P = 0.05), higher plasma proANP (P = 0.05) and lower albumin concentration (P = 0.013). The effect of higher plasma proANP (P = 0.018) and lower albumin concentration (P = 0.013) was left as an independent variable in the Cox regression model. In conclusion, in the studied group of particularly fragile dialysis patients, the elevated proANP level appeared to be an independent predictor of mortality, whereas the NT-proBNP concentration did not exhibit a significant effect.