Peritoneal Dialysis (PD) is a commonly used treatment for end stage renal failure, and the most commonly used dialysate contains unphysiological amounts of glucose, a high proportion of which is absorbed. Recent analysis of the Global Fluid Study, has established that in non-diabetic prevalent patients on PD a random glucose level is dependent on dialysate glucose load and is a predictor of death. By utilising clinical data and additional biosamples collected for the NIHR funded PD-CRAFT study, the investigators aim to confirm this finding, define the relationship between dialysate glucose exposure according to prescription regimes and glycaemia, define the most useful biomarker to monitor glycaemia , and establish the role that impaired insulin sensitivity plays in blood glucose levels. Furthermore the investigators will explore the hypothesis that insulin resistance is associated with disturbance of the carnitine/acetyl-carnitine equilibrium that might benefit from intra-peritoneal carnitine supplementation.