Long-term outcome in PD morbidity and mortality

Two main dialysis modalities exist to treat chronic uremic patients: hemodialysis (HD) and peritoneal dialysis (PD); the latter is used less extensively than the former, but its penetration greatly differs among countries and among different regions of the same country. The comparison of the outcome in PD and HD is not easy, since many factors (mainly criteria for patient selection) oppose an adequate balance of the many factors influencing the patient's outcome. After the very different results in favor of HD in the early '80s, the difference in patient survival between PD and HD is progressively reduced and, in the '90s, many studies have shown comparable results. As far as the cardiovascular system is concerned, PD has some advantages versus HD due to stability in blood volume and electrolyte concentration, and lack of hyperkinetic circulation due to artero-venous fistula. However, this does not positively affect cardiovascular mortality whose prevalence is similar between the two modalities. Factors suggested to explain this unexpected result, namely: some degree of thrombophilia in PD, greater lipid metabolism derangement, and chronic fluid overload. Probably for these reasons, the de novo appearance of cardiovascular disease is similar in both modalities. Technique success is definitely worse in PD in nearly all the papers published. Many improvements in peritoneal solution biocompatibility have been made during the late '90s, but their effects on long-term outcome have to be defined.