Title: Optimising early dialysis catheter function – the UK Peritoneal Dialysis Outcomes and Practice Patterns Study
Funder: Department of Health and Social Care

Abstract: Background In the UK there are 23,079 treated with haemodialysis and 3,831 treated with peritoneal dialysis (PD) [3] with the cost of renal replacement therapy being about 2% of the NHS budget. The use of peritoneal dialysis is suboptimal and highly variable between dialysis centres, despite equivalent survival outcomes compared to haemodialysis, clear patient benefits and established cost savings to the NHS. A major reason for this is the variation in pathways for insertion of PD catheters, essential for the treatment to work. For example, some units only undertake surgical insertion whether others practise surgical and medical insertion techniques. Having a medical insertion technique available gives flexibility, but on national audit these were twice as likely to fail (7% vs 14% failure at 3 months). Catheter-related complications are associated with considerable morbidity, disruption, and discomfort for patients and may result in their not being established on their dialysis modality of choice. These complications also have significant health economic costs due to the need for additional procedures, hospital admissions and treatment failure contributing to the 10-fold difference in PD use between centres. Aims Our aim is to establish the optimal pathway (or pathways) for PD catheter insertion and whether it is advantageous, in terms of patient outcome and cost effectiveness, for dialysis units to invest in developing medical as well as surgical pathways. Plan of investigation We will undertake a multi-centre prospective cohort study to establish whether the outcomes following catheter insertion are due to catheter insertion pathway (e.g. tendency to choose medical or surgical insertion), other factors at the dialysis unit level (e.g. policies such as the use of urgent start PD, team organization, skill availability and patient volume, waiting list and theatre organization), and/or patient-level factors (e.g. case-mix, urgent start). An average of 30 sequential patients will be recruited from each of 45 randomly selected dialysis units at the point of first PD catheter insertion and followed for at least 6 months or until they reach a composite catheter-related outcome (further operative intervention, failure of catheter function, catheter-related hospital admission, infection or death). Patients unsuitable for surgical insertion will be excluded, as the purpose of this study is to inform the choice between medical and surgical among patients eligible for both. Catheter survival will be analysed using Cox regression adjusting for potential confounders. To evaluate unit-level factors we will employ analytic designs including instrumental variable techniques to control for confounding and treatment-by-indication bias. For example, while the likelihood of an individual patient having a medical rather than a surgical catheter insertion may depend on that patient s characteristics (e.g. urgent start), the proportion of patients within each unit with medical insertion is more a function of the availability and policy that underpin use of this approach. We will have sufficient power to detect a hazard ratio of 1.7 between the two main pathways, (1.8 was observed in the national audit). We will undertake pre-study work to ensure that our survey instrument is able to identify patient preferences and the detail/policies of catheter insertion pathways, and will utilise the recently developed survey instruments for the international PDOPPS study to capture confounders and additional practice patterns. To complete our analysis we will use our study data, enriched by hospital episodes and statistics, to undertake a health economic analysis using the model developed by NICE for Clinical Guideline 125. Potential benefits to patients and NHS By providing the evidence that identifies the optimal pathway to PD catheter insertion we expect to achieve benefits for patients (improved outcomes, accommodation of preferences, access to PD) and for the NHS (demonstration of cost effectiveness).

Lay abstract: Peritoneal dialysis (PD) and haemodialysis (HD) are the main life-sustaining artificial treatments available to remove waste products from people who have kidney failure and are equally effective. PD involves the exchange of fluid in and out of the abdominal cavity via a catheter that is placed for this purpose. PD has advantages as a home treatment giving the user more personal freedom and flexibility, allowing people to continue to work. It is also less expensive than HD which generally requires patients to attend hospital 3 times per week for treatment lasting 4 hours per session. Despite the advantages of PD, it is used much less than HD in the UK with wide variations in its use between dialysis centres. One factor that explains the variation in the successful use of PD is the occurrence of early complications such as when the catheter does not work well. If the catheter does not work properly there are significant implications: negative psychological impact, disruption of lifestyle and work, periods of hospitalisation, extra operations and the possible need to change to HD. This research aims to understand the best practices that exist for PD catheter insertion, and the way that services are organised to support them. We are particularly interested in the clinical pathways that are associated with catheters working first time, and lead to the best outcomes. We think that by understanding these we will be able to recommend optimal practices to improve outcomes, which can then be audited. Patient benefits of this research will include more consistent and effective placement of PD catheters and a reduction in the occurrence of the complications. Benefits to the broader NHS will include cost savings due to a reduced requirement for repeat procedures, improved patient safety and increased use of PD as a therapy.

Research activity codes: 8.1 ORGANISATION AND DELIVERY OF SERVICES
Health categories: RENAL AND UROGENITAL