Comparison of 4- and 8-h dialysis sessions in thrice-weekly in-centre haemodialysis

Background. Longer dialysis sessions may improve outcome in haemodialysis (HD) patients. We compared the clinical and laboratory outcomes of 8- and 4-h thrice-weekly HD. Methods. Two-hundred and forty-seven HD patients who agreed to participate in a thrice-weekly 8-h in-centre nocturnal HD (NHD) treatment and 247 age-, sex-, diabetes status-and HD duration-matched control cases to 4-h conventional HD (CHD) were enrolled in this prospective controlled study. Echocardiography and psychometric measurements were performed at baseline and at the 12th month. The primary outcome was 1-year overall mortality. Results. Overall mortality rates were 1.77 (NHD) and 6.23 (CHD) per 100 patient-years (P = 0.01) during a mean 11.3 +/- 4.7 months of follow-up. NHD treatment was associated with a 72% risk reduction for overall mortality compared to the CHD treatment (hazard ratio = 0.28, 95% confidence interval 0.09-0.85, P = 0.02). Hospitalization rate was lower in the NHD arm. Post-HD body weight and serum albumin levels increased in the NHD group. Use of antihypertensive medications and erythropoietin declined in the NHD group. In the NHD group, left atrium and left ventricular end-diastolic diameters decreased and left ventricular mass index regressed. Both use of phosphate binders and serum phosphate level decreased in the NHD group. Cognitive functions improved in the NHD group, and quality of life scores deteriorated in the CHD group. Conclusions. Eight-hour thrice-weekly in-centre NHD provides morbidity and possibly mortality benefits compared to conventional 4-h HD.