Is Automated Peritoneal Dialysis Better for Urgent-Start Dialysis Compared to Hemodialysis?

Written by: Dr. Vamsidhar Veeranki

Selecting the appropriate dialysis modality for an individual with ESRD is critical and needs to factor in patient preferences as well as social, financial, and geographical logistics. Despite its advantages, peritoneal dialysis (PD) as a modality of renal replacement therapy (RRT) remains underutilized, with only ~10% of dialysis patients engaged globally. In 2021, 83.8% of U.S. ESRD patients initiated in-center HD, down from 91.4% in 2008, while PD initiation rose to 12.7%, more than doubling from its 2008 nadir. Unfortunately, up to 70% of patients begin dialysis without a structured plan, the most common approach is starting with a hemodialysis (HD) via a central venous catheter, despite the associated risk of higher mortality, infections, and hospitalizations.  In addition, HD is 1.25–2.35 times costlier than PD in most developed countries, and PD offers similar or superior outcomes with better preservation of residual kidney function and the benefits of home-based therapy. Moreover, PD is “greener” and associated with less water and power utilization than HD. Peritoneal dialysis (PD) is typically initiated in an elective setting, known as Planned Peritoneal Dialysis (PPD), where patients begin PD approximately two weeks post-catheter insertion. This delayed initiation allows for optimal healing and reduces complications such as dialysate leaks, infection, and catheter dysfunction. This practice stems from traditional recommendations by the ISPD and ERBP guidelines to delay PD initiation by at least two weeks after catheter insertion to prevent complications, despite being based on weak evidence. Urgent start PD (USPD) refers to cases where PD is initiated within 48–72 hours of catheter insertion. This implies the urgency of starting RRT in a patient who may not be able to wait for two weeks and emphasizes PD as an alternative to urgent HD while avoiding the need for additional access in patients who plan to continue with PD. USPD may be a window of opportunity that could reduce healthcare costs and improve patient outcomes while boosting overall PD adoption. USPD offers comparable outcomes to planned PD, minimizing complications associated with urgent-start HD, such as infections, bacteremia, bleeding, and central venous stenosis.

Though studies comparing the PPD  and USPD are scarce, an RCT by Ranganathan et al. noted a significantly higher incidence of peri-catheter leaks in those initiated within 1 week of PD catheter insertion compared to those initiated at 2 or 4 weeks. However, recent advancements in dialysis, particularly with automated peritoneal dialysis (APD), have expanded treatment options, especially in urgent-start settings. APD offers not only physiological benefits, like fewer hemodynamic fluctuations and continuous solute clearance but also greater patient comfort. Compared to manual PD, APD exerts less intraabdominal pressure, promoting incision healing and reducing complications such as leakage. Despite its suitability for urgent-start PD, the role of APD remains mostly unexplored. Comparative efficacy and safety between APD and HD in urgent-start settings are also under-researched, with most evidence based on retrospective or observational studies. A recent KI Reports article aims to fill this research gap by comparing the outcomes of APD and HD for urgent-start dialysis in ESRD patients. Key outcomes assessed included dialysis-related complications, PD catheter longevity, peritonitis-free survival, patient survival, and cost-effectiveness.

Study Design: 

Prospective, multicenter RCT included 116 ESRD patients requiring urgent-start dialysis, conducted across 11 hospitals from March 2019 to December 2020, with the final follow-up in December 2021 (12-month follow-up). The flow chart of the study is shown in Figure 1.

Randomization: Patients were randomized in a 1:1 ratio by block randomization method into two groups: APD and HD, with each group consisting of 58 patients.

Major Inclusion Criteria:

• Aged 18 to 80 years.

• Required urgent initiation of dialysis due to late presentation or rapid progression of renal disease and lacked pre-established functional dialysis access.

Exclusion Criteria:

• Contraindications to PD or HD

• Patients with indication for emergency RRT such as severe volume overload and pulmonary edema, severe hyperkalemia, uremic encephalopathy

• Severe liver failure

• Uncorrectable shock, malignancy, or psychiatric disorders.

• Pregnancy or lactation

• Inability or unwillingness to provide informed consent for the study

Intervention:

The study protocol for both groups is illustrated in Figure 2. Consequently, while patients in the APD group commenced RRT via APD within 3 days of catheter insertion, those in the HD group required initiation through a CVC for hemodialysis, with PD delayed until 2 weeks post-catheter insertion.

Outcome Measures:

1. Primary outcome: 

Incidence of dialysis-related complications – A composite of non-infectious and infectious complications 

• Non-infectious complications: PD catheter malposition/obstruction, leakage, hernia, bleeding around the catheter, and thrombosis

• Infectious complications: PD catheter-related tunnel infection, peritonitis, and CVC-related infection

• Secondary outcomes:

• PD catheter survival rate

• Peritonitis-free survival rates

• Patient survival rate

• Total direct medical cost and 

• Duration of initial hospitalization

Results:

The participants had a mean age of 52.2 ± 14.2 years, with 66.4% being male. The median time to dialysis initiation after catheter insertion was 4 days in the APD group. Baseline characteristics are shown in Table 1.

Dialysis related complications:

At the 1-year follow-up, the incidence of dialysis-related complications was significantly lower in the APD group compared to the HD group (25.9% vs. 56.9%, P = 0.001). The difference is due to the significantly lower rates of non-infectious complications in the APD group compared to the HD group (15.5% vs. 34.5%, P = 0.032). Although infection-related complications were more common in the HD group, this difference was not statistically significant (10.3% vs. 22.4%, P = 0.132). As shown in table 2, the predominant complication among the HD group was the catheter-related bleeding which contributed to the major difference between the two groups.

6-week outcomes:

Within 6 weeks, complication rates were significantly lower in the APD group (15.5%) compared to the HD group (36.2%, P = 0.020). The HD group had higher instances of CVC-related bleeding (P = 0.006), as well as CVC infections (5.2%) and thrombosis (3.4%). In contrast, the APD group showed slightly higher rates of PD catheter obstruction (5.2%) and leakage (3.4%), but these differences were not statistically significant. PD-related infections were similarly distributed between the two groups.

Secondary outcomes:

There was no significant difference in PD catheter survival or peritonitis-free survival between the APD and HD groups. The 1-year patient survival rate was the same in both groups. While the length of hospital stay was similar between the two groups, the total direct medical cost for the initial hospitalization was significantly lower in the APD group.

Discussion:

This study advances the understanding of renal replacement therapy by introducing and evaluating APD as an effective method for urgent-start dialysis in patients with ESRD. The study distinguishes itself by standardizing APD protocols based on extensive clinical experience and offering a longer follow-up period compared to previous studies. Notably, it incorporates health economic analyses, expanding the assessment beyond clinical outcomes alone. The key finding of this multi-centered RCT was the significantly lower incidence of dialysis-related complications in the APD group compared to the HD group at one-year follow-up. This result is consistent with prior research and can be attributed to the avoidance of CVCs in the APD group, thus reducing risks like thrombosis, CVC-related infections, and HD-associated complications such as bleeding due to anticoagulation. While previous studies have demonstrated a significant advantage of PD over HD in reducing dialysis-related complications in patients initiating urgent-start dialysis, the majority of these findings, with the exception of one, are based on observational studies. Moreover, this study is notable for being the first to utilize APD as a modality to address complications like peri-catheter leak, and exit site bleeding which have been reported in previous studies involving urgent start PD. The study showed that urgent initiation of APD did not result in an elevated risk of early PD complications (e.g., peritonitis, hernia, leakage), highlighting its safety even in acute settings. There were no significant differences in PD catheter survival rates, peritonitis-free survival, or overall patient survival between the APD and HD groups. These findings suggest that APD is not only a safe alternative to HD in urgent-start scenarios but may also provide better long-term outcomes, withlower complication rates. Moreover, APD appears to offer greater patient tolerability, potentially improving treatment adherence. The study's limitations, including its open-label design, lack of blinding, the potential for detection bias, and limited generalizability to populations with larger body mass indices (mean BMI of 24.9 in APD and 23.7 in HD group) must be acknowledged. Additionally, the absence of patient-reported outcomes (e.g., quality of life) represents a gap for future research. Despite these limitations, the findings emphasize the utility of APD as a viable, safe, and cost-effective modality for urgent-start dialysis, with the potential to improve long-term outcomes and reduce healthcare costs.

In conclusion, this study contributes significantly to the growing body of literature supporting the expanded use of APD in urgent-start dialysis scenarios, highlighting its clinical and economic benefits and positioning it as a promising alternative to HD for managing ESRD patients requiring unplanned dialysis initiation. Expanding USPD is vital for increasing home dialysis use, and accommodating patients’ needs while decreasing risk and the need for additional surgeries.