FREDI-cal: Frequent Dialysis and Markers of Cardiac Strain and Injury, Physical Fitness, Habitual Physical Activity and Quality of Life

Individuals with kidney failure are kept alive using dialysis machines designed to remove toxic substances and excess fluid from the blood. Standard dialysis is undertaken three times a week at a dialysis unit, supported by a team of specialist dialysis nurses (so called in-centre haemodiafiltration or ICHDF). Each session lasts approximately 4 hours, during which time the fluid and toxins which have built up since the last session of treatment are removed from the blood. The rapid removal of fluid that takes place using this technique often causes unpleasant symptoms such as cramps and dizziness, as well as a "hangover", which may last several hours. It can also cause problems with the heart in the long-term.

In recent years, individuals requiring dialysis have been able to choose between standard ICHDF or having haemodialysis at home (HHD) using a convenient table top machine called NxStage System One. This device is used more frequently than in ICHDF and for shorter sessions. As a result, the amount of fluid removed during each session is less than with ICHDF. This may be beneficial to the heart, but may also make these individuals feel generally better, which may make them want to be more physically active. It may also reduce the time taken to recover from any symptoms experienced after dialysis.

Over a 12 month period, markers of heart damage (using blood tests and scans of the heart) in patients receiving frequent HHD will be studied and the results will be compared with a group of patients receiving ICHDF. The study will also compare any symptoms they may have, how fit they are, how physically active they are and how well they sleep. In addition, the investigators will assess how well fluid balance is maintained in each group and measure the changes in their remaining kidney function during this time.