Home haemodialysis is a common and relatively inexpensive form of dialysis in New Zealand that provides good quality of life. However, survival is still poor compared to the general population and 67% of patients die from cardiovascular disease. The ""SOLID Trial"" is an on-going study throughout New Zealand evaluating an intervention which aims to improve these patients' cardiovascular outcomes. The intervention involves reduced salt dialysis, which we expect will improve cardiac structure and function, and thereby reduce the risk of sudden cardiac death. If the intervention works, it will quickly become standard practice locally and internationally. The Mac-SOLID Study is new research that extends the SOLID Trial to ensure that reduced salt dialysis is not otherwise harmful to the heart through making dialysis less stable. If these two studies are positive, this intervention will be one of the few in medicine to provide health benefits at no added cost.