Burden of kidney disease and the burden of proof

End-stage kidney disease (ESKD) continues to be a worldwide problem, with an increasing number of patients undergoing kidney replacement therapy. Kidney failure has a negative impact on patients’ quality of life. Kidney failure affects all aspects of life, including the ability to work, social functioning, physical activity, overall well-being and life satisfaction. As the benefits and disadvantages of different dialysis modalities continue to be debated among kidney care practitioners, it is important to evaluate and understand the impact of each modality on quality of life. In the past few years, we have witnessed the kidney care community moving towards patient-centred treatments, de-emphasising clearance targets or length of survival, as reflected in the latest International Society for Peritoneal Dialysis guidelines for delivering high-quality peritoneal dialysis (PD). In this issue of Peritoneal Dialysis International (PDI), Li et al. report the results of a randomised controlled study that aimed to evaluate the impact of dialysis modality (in-centre haemodialysis (HD) and PD) on health-related quality of life (HRQoL). Seven hundred and twenty-five patients with ESKD across 36 dialysis centres in China were randomised to either in-centre HD or PD. Patients completed the HRQoL survey (Kidney Disease Quality of Life-Short Form (KDQOL-SF)) after 48 weeks. The focus was on the ‘burden of kidney disease’ domain, assessed by four parameters reflecting the degree of interference of kidney disease on patients’ lives. The study was structured statistically as a non-inferiority analysis of PD compared to HD. The change in ‘burden of kidney disease’ from baseline to 48 weeks after randomisation was similar between study groups and satisfied non-inferiority for PD. Patients receiving PD had more adverse events leading to hospitalisations and serious adverse events. PD patients also had more gastrointestinal problems and hypokalaemia. As a secondary outcome in this trial, mortality was lower among PD patients versus in-centre HD in the intention to treat analysis. The authors concluded that PD is non-inferior to HD in the ‘burden of kidney disease’ scale after 48 months. When considering the generalisability of the results to other patient populations, the baseline characteristics of the study population deserve comment. The study cohort consisted of relatively younger Chinese patients with less comorbidity than what is seen in many other analyses. The mean age of the cohort was 49.8 years, only 16.3% had a history of cardiovascular disease (CVD) and 27.8% had diabetes. Contrast this cohort to the 2021 annual report of the United States Renal Data System where the mean age of incident ESKD patients is 62.7 years, 66.2% had CVD and 60.6% had diabetes. According to the UK Renal Registry, the median age of patients starting kidney replacement therapy was 64.2 years, and 30.4% had diabetes as the primary cause of kidney disease. Generalisability is further challenged by the observation that only 3.5% of the participants were on automated peritoneal dialysis (APD), and none were using icodextrin. This is very different from PD practice in many high-income countries. Patients from Australia/New Zealand, Canada, the United Kingdom and the United States use APD predominantly, with rates ranging between 66% in Australia/New Zealand and 83% in the United States. Icodextrin is used by more than 40% of patients in Australia/New Zealand, Canada, the United Kingdom and Japan and 15% of patients in the United States. Li et al. report a higher proportion of serious adverse events and adverse events leading to hospitalisations in patients receiving PD compared to in-centre HD. However, the details of those adverse events are not specified. With regard to infectious complications, the proportion of infections was higher in the PD arm (largely driven by peritonitis), however, infectious event rates, infection-related morbidity and infections by access type are not provided. In an attempt to quantify and standardise the measurement of quality of life in kidney disease, a number of