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Urgent-Start PD: Taking The Road Less Traveled in Dialysis Initiation

By Carlo Trinidad, MD (@hellokidneyMD)

AcademicCME (www.academiccme.com) is accrediting this educational activity for CE and CME for clinician learners. Please go to https://academiccme.com/kicr_blogposts/ to claim credit for participation.

Unplanned dialysis initiation occurs when a patient does not start dialysis using their chosen modality, dialysis initiation with a central venous catheter, and/or dialysis initiation during hospitalization or under emergent conditions. In fact, studies report the prevalence of unplanned dialysis initiation is as high as 40-60%. “Crash” or unplanned dialysis starts are both associated with increased patient morbidity and mortality and lower quality-of-life scores. In many Western countries, the predominant protocol for unplanned starts involve the utilization of urgent-start HD.

Urgent-start HD, and its usage of central venous catheters (CVCs), is mired with problems. The CHOICE study demonstrated that among vascular access, CVCs had the highest annual mortality rates. The use of CVCs is also associated with a 39% higher risk of infection-related death compared to arteriovenous fistulas. The higher risk for mortality in patients with CVCs stemmed from multiple factors, including increased risk of infections and bacteremia. These data strongly supported the position of practice guidelines minimizing the use of CVCs. Despite compelling evidence, USRDS data reveal that 86.9% of incident ESRD patients began RRT (renal replacement therapy) with HD, and 80% of patients were initiated using a central venous hemodialysis catheter.

Figure 1. Global comparisons of gross national income (GNI) per capita, prevalence of kidney replacement therapy (KRT) per million population (PMP), relative use of peritoneal dialysis (PD), and frequency of central vein catheter (CVC) use among prevalent patients receiving hemodialysis (Lee et al 2021)

Urgent-start PD is the initiation of peritoneal dialysis in patients with newly-diagnosed ESRD who are not yet on dialysis. Unlike conventional-start PD where therapy is initiated at least 2 weeks after PD catheter placement, urgent-start PD expedites treatment to within two weeks of PD catheter insertion. Key elements to a successful urgent-start PD program include the availability of operators who can insert PD catheters within 48 hours and trained staff who are able to use the catheter properly immediately after placement. Observational data consistently shows low complication rates (catheter leakage and dysfunction, abdominal wall complications, peritonitis) associated with urgent-start PD. However, compared with conventional start PD, urgent-start PD may increase the risk of dialysate leak.These leaks were mostly minor and were reduced with the use of low starting intraperitoneal volumes and proper positioning.

Figure 2. Urgent-start PD complications - visual abstract (Hernandez-Castillo et al. 2020)

Various observational prospective and retrospective studies signal the comparable efficacy and superior safety of urgent-start PD versus urgent-start HD. Alkatherri et al reported that there was no difference in overall mortality between PD versus HD patients. However, the HD group had higher incidence of bacteremia and infection-related mortality. In a retrospective study of 178 ESKD patients, more HD patients developed dialysis-related complications (24.4% vs. 5.2%) compared to PD. These included bacteremia, bleeding and thrombosis resulting in CVC removal and reinsertion. Additional surgical procedures also put patients at increased risks for complications. An open label study of 184 patients receiving PD or HD with a follow up of 180 days to 2 years showed no difference in mechanical complications between the two groups.

A large Canadian retrospective cohort compared the outcomes of patients initiated with PD versus those initiated with HD then switched to PD. PD-switch patients fared poorer than their PD-first counterparts in terms of treatment failure (AHR 1.37; 95%CI: 1.26 to 1.49) and all-cause mortality within the 90 days (AHR 1.82; 95% CI: 1.52 to 2.18 ) and within 91-180 days (AHR 3.11; 95% CI: 2.43 to 3.98). This was attributed to higher rates of peritonitis as well as rapid loss of residual kidney function among patients who were started on HD. Higher rates of peritonitis were associated with lower residual kidney function at the time of transfer to peritoneal dialysis.

A Cochrane systematic review sought to establish which among urgent start PD or urgent start HD was superior in terms of complication rates and patient survival. Urgent‐start PD was the clear winner in terms of a lower incidence of bacteremia (RR 0.13). However, the data was less clear in terms of peritonitis, exit-site infection, catheter malfunction and re-adjustment, exit-site bleeding and patient survival. The authors noted that all outcomes (save for bacteremia) were graded as very low quality of evidence, as all included studies were observational.

Figure 3.Urgent‐start PD versus urgent‐start HD, Outcome 1: Bacteraemia (Htay et al. 2021)

A recently published KI reports article by Parapiboon et al. was the first randomized controlled trial to date comparing the outcomes between urgent-start PD (N=104) and urgent-start temporary HD with CVCs (N=103) in ESKD patients. Patients with conditions requiring emergent dialysis (e.g. severe acute pulmonary edema, severe life-threatening hyperkalemia, uremic pericarditis) were excluded, as well as those with medical or social contraindications for the performance of PD.

The urgent-start PD protocol involved the initiation of nurse-performed rapid PD exchanges immediately after PD catheter insertion, followed by gradually increasing dwell volume from 800 mL to 2L within 2 weeks. Patients of both groups were eventually transferred to the chronic PD program because of Thailand’s “PD First Policy”. For urgent-start temporary HD patients, a PD catheter was placed after HD has been performed for at least 3 sessions (8-15 days). Chronic PD was then started 2 weeks after PD catheter insertion.

The urgent-start PD group had a much lower 6-week composite complication rate (19% vs 37%, RR 0.52, 95% CI 0.33–0.83) as well as dialysis-related complications (4% vs. 24%, RR 0.16, 95% CI 0.06–0.44). However, there was no difference in operation-related, catheter-related, and infection-related complications when looked at individually. Consistent with previous observational studies, the incidence of peri-catheter leakage was higher in the urgent-start PD group but was easily resolved by decreasing dwell volumes. Mortality rates were comparable between the two groups. The study is summarized nicely by the wonderful visual abstract of @divyaa24 below.

Figure 4. RCT of Urgent-start PD vs Urgent-start temporary HD - visual abstract (Parapiboon et al. 2022)

This randomized study provides higher quality of evidence of the safety and viability of urgent-start PD that was lacking in prior observational studies. Despite this, major barriers like the lack of skilled operators for emergent PD catheter placement and limited facility capacity for PD services hinder the proliferation of urgent-start PD programs.

A global perspective of dialysis showed that a nation’s wealth does not correlate with PD utilization rates and is not an impediment to the implementation of PD programs. While higher income countries like the US and Japan have low PD utilization, lower income countries like Mexico, Guatemala and Thailand have very successful PD first programs with >50% of their ESRD patients on PD. Furthermore, urgent-start PD may offer a cost-saving approach for the initiation of dialysis. Urgent-start PD represents a safe, effective and relatively cheaper option for ESRD patients transitioning to dialysis and certainly deserves to be given serious consideration as a viable option around the world. However, additional training, personnel and resources would have to be allocated to make urgent start PD successful.

AcademicCME (www.academiccme.com) is accrediting this educational activity for CE and CME for clinician learners. Please go to https://academiccme.com/kicr_blogposts/ to claim credit for participation.

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