People with kidney disease are often anaemic, which can reduce their quality of life, with symptoms of fatigue, dizziness, and shortness of breath. Anaemia is a state in which the quality and/or quantity of circulating red blood cells are below normal. The kidneys produce a substance called erythropoietin which stimulates the bone marrow to produce red blood cells. Loss of erythropoietin production is a major cause of anaemia in renal failure. Anaemia is measured by blood haemoglobin levels, and can be treated by injections of erythropoietin in drug form. However, at present we do not know enough about the safety of the drugs. This study aims to assess if treatment dose is related to the survival of patients with chronic kidney disease on haemodialysis (a treatment that takes over the work of the kidneys if they fail). This study plans to use an instrumental variable analysis, which is a technique that uses a variable that is related to the factor under study but is not directly associated with the outcome or any other factor that might serve as an alternative explanation for a study’s result.

The optimal treatment strategy for the dealing with renal anaemia is controversial and there is a risk that the current treatment guidelines may prevent patients without major co-morbidity from receiving the maximum benefit from treatment. In recent years, there has been a decrease in erythropoiesis stimulating agent (ESA) use, dose and average achieved haemoglobin levels, with fewer patients having haemoglobin levels >120 g/L and more patients having haemoglobin within the 100-120 g/L target range. This research into anaemia management with UK Renal Registry (UKRR) data will give insights into patient safety. Potential benefits to patients are that any new evidence on the use of ESA therapy will be made available to researchers and clinicians. Results from this study could help inform the need for further randomized controlled trials into this area of research, which in turn could be translated into every day clinical care, enhancing patient quality of life.