In Focus Transition between home dialysis modalities: another piece in the jigsaw of the integrated care pathway

The integrated use of dialysis modalities alongside transplantation over a lifetime of renal replacement is often necessary and well established. In general, outcomes are more favourable when using home-based treatments, but what is less certain is the value of using these modalities sequentially. To explore this, using data from the Australian and New Zealand Dialysis and Transplantation (ANZDATA) registry, patients using peritoneal dialysis (PD) followed by home haemodialysis (HHD) were compared using propensity matching to those treated by PD and HHD only. For combined patient and technique survival, or patient survival only, outcomes for those using integrated home therapies (PD followed by HHD) had similar outcomes to HHD alone, whereas those using PD only fared less well. The proportion of patients on PD transitioning to HHD was very small, as was the absolute number of patients using PD to HHD integrated pathway, so caution is needed in generalizing these results to a wider patient population, but the concept of integrating home therapies in this way is supported by the findings. The study also points to a need for a better understanding of what happens at the transition between modalities so as to improve patient outcomes and experiences of dialysis care. The concept of integrating different renal replacement modalities is not new. For many patients, dialysis is the bridge to or between kidney transplantation where it provides a welcome safety net and an integrated care model that incorporates PD and haemodialysis (HD) with transplantation is well established [1, 2]. In truth, younger patients with a lifetime of renal replacement in front of them will almost always require several modality switches over the years, and there is some evidence that the use of more than one dialysis modality can confer benefits. PD has theoretical advantages as a preferred initial dialysis modality, such as the relative preservation of residual kidney function [3, 4] or sites for vascular access [5] and costeffectiveness [6], supported by empirical evidence of a relative survival advantage compared with centre-based HD during the first year or more of treatment and better overall survival in patients using more than one modality [7–11]. Nested within this generalizable integrated care approach is what has been termed the ‘Integrated Home Dialysis Model’, for example, PD followed by home haemodialysis (HHD). However, it is not known whether the early advantage of PD is still evident under these circumstances or whether it is even detrimental. Matched studies from the UK Renal Registry comparing the outcomes of patients starting with PD versus HHD have suggested that the latter is associated with better outcomes [12, 13]. It is as an attempt to answer this question that NadeauFredette and colleagues have analysed data from the ANZDATA registry, published in this edition of Nephrology Dialysis Transplantation [14]. They have also recently published an analysis of PD versus HHD as incident treatments from the same database [15]. Their approach is to compare the outcomes of three patient groups, those who had PD only, HHD only and those who transitioned from PD to HD, taking combined patient and homedialysis technique survival as their primary end point (although patient survival alone was also analysed). This type of analysis throws up two major methodological problems: first, how to match these patient groups sufficiently well as to reduce casemix bias, and second, how to account for the fact that patients undergoing sequential therapies need to survive for a period on the first treatment before they can transition, so-called immortal time bias. Their approach to the first is to use propensity matching of baseline patient characteristics, so as to select from