Investigators at Imperial College Hospital NHS Trust and North Bristol NHS Trust in the U.K. compared extended TT (6 hours) and standard TT (4 hours) on HD in a randomized, crossover study that included 29 patients. During the extended TT phase of the study, serum phosphate decreased significantly from 1.67 g/dL before treatment to 1.27 g/dL after 6 hours of treatment.
During the standard TT phase, serum phosphate increased significantly from 1.51 g/dL before treatment to 1.94 g/dL after 4 hours of treatment.
In addition, during the standard TT phase, researchers observed a significant increase in extracellular water, whereas during the extended TT phase, patients had no significant change in hydration status.
The study cohort included 27 men and 2 women with a mean age of 65 years.