The effect of long, slow haemodialysis on patient survival

Background. Long, slow haemodialysis (24 h/week) has been associated with excellent patient survival and reduced cardiovascular mortality. Comparisons of patient survival have only been possible with registry data and other published series which do not control for individual patient characteristics. This retrospective study compares actuarial patient survival between a unit using long, slow haemodialysis (Tassin) and one employing 'conventional' haemodialysis (Nottingham). Methods. All patients undergoing haemodialysis at each centre since 1980 were included (Tassin, 452 patients; Nottingham, 282 patients). Actuarial curves of patient survival were calculated by the life-table method and log rank test was used to compare data. Patients were grouped as follows: standard (SRD) and non-standard (NSRD) renal diseases; diabetics and non-diabetics; patients with and without cardiovascular antecedents; risk stratification based on age and comorbidity. Results. Overall survival was significantly better in Tassin. This difference was also noted for patients with SRD and non-diabetics (both P<0.001) and for those with (P = 0.007) and without (P<0.001) cardiovascular antecedents. Survival did not differ significantly for NSRD and diabetics. Survival was better in Tassin in low-risk (P<0.001) and medium-risk (P<0.001) groups, but not for high-risk (risk stratification). Conclusions. Overall survival is increased on long, slow haemodialysis. Although the benefits are seen in the most favourable prognostic categories, they are also present in patients with comorbid illness (medium-risk group) and pre-existing cardiovascular disease.