Comparison of mortality in ESRD patients on convective and diffusive extracorporeal treatments

Background. The aim of this study was to evaluate the effect of convective [hemodiafiltration (HDF) or hemofiltration (HF)] versus diffusive treatments [hemodialysis (HD)] on end-stage renal disease (ESRD) patient mortality and dialysis-related amyloidosis (DRA) using data from the Lombardy Registry. Methods. For this purpose, 6,444 patients (aged 56.4 +/- 15.6 years, females 39.5%, diabetics 10.6%) who started renal replacement therapy (RRT) on HD, HDF, or HF between 1983 and 1995 were considered. A total of 1,082 patients were treated with HDF or HF (first choice in the case of 188), with a median follow-up of 29.7 months. The median follow-up of the 6,298 patients on KD (first choice in the case of 6256) was 22.4 months. The time of survival on dialysis to carpal tunnel syndrome (CTS) surgery was evaluated as a hard marker of DRA morbidity. Survival was compared by means of the Cox proportional regression hazards model, using CTS surgery and all deaths as events for morbidity and mortality, respectively. Explanatory covariates were age, gender, and comorbidities; dialysis modality was tested as a time-dependent covariate. Results. The relative risk (RR) for CTS surgery was significantly higher in older patients [RR = 1.04 per year of age on admission to RRT, 95% confidence interval (CI) 1.02 to 1.06; P = 0.0001], in diabetics (RR = 2.63, 95% CI 1.30 to 5.31; P = 0.0007), and in patients with heart disease (RR = 5.36, 95% CI 2.27 to 12.68 P = 0.0001). Adjusting for age and diabetic status, the RR for CTS surgery was 42% lower in the patients treated with HDF or HF (RR = 0.58, 95% CI 0.35 to 0.95, P = 0.03). The RR for mortality, adjusted for age, gender, and comorbidities, was 10% lower in patients treated with HDF or HF (RR = 0.90, 95% CI 0.76 to 1.06; P = NS). Conclusion. These results support the hypothesis that convective treatments are associated with a nonsignificant trend toward better survival and significantly delay the need for CTS surgery. An older age and the presence of diabetes and heart disease are other important risk factors for CTS surgery. These results could have an important clinical impact given the relevance of DRA in dialysis patient morbidity.