What are the differences between haemodialysis (HD) and peritoneal dialysis (PD) in terms of patient selection and management?

Haemodialysis vs Peritoneal Dialysis: Patient Selection and Management

Both haemodialysis (HD) and peritoneal dialysis (PD) are clinically equivalent modalities with similar mortality outcomes, but the choice should prioritize patient autonomy, lifestyle preferences, and specific clinical contraindications rather than assuming one modality is universally superior. 1

Clinical Outcomes and Survival

• Clinical outcomes across all dialysis modalities are largely similar, with no definitive survival advantage of one modality over another in most patient populations 1
• In adults, PD may reduce the risk of all-cause death based on limited RCT data (RR 0.53,95% CI 0.32 to 0.86), though observational data shows uncertain effects 2
• PD demonstrates a potential early survival advantage in the first 1.5-2 years of dialysis, particularly in the first 3 months, after which the survival benefit equalizes or reverses compared to in-center HD 3
• In children, there is little or no difference between HD and PD on all-cause death (RR 0.81,95% CI 0.62 to 1.07) or cardiovascular death (RR 1.23,95% CI 0.58 to 2.59) 2

Residual Kidney Function Preservation

• PD may reduce the risk of residual kidney function (RKF) loss compared to HD (RR 0.55,95% CI 0.44 to 0.68), which is clinically significant for patient outcomes 2
• The effect of PD on absolute RKF measurements at 6,12, and 24 months remains uncertain due to high heterogeneity in studies 2
• Preservation of RKF is particularly important as it contributes to better volume control, toxin clearance, and overall patient well-being 4

Absolute and Relative Contraindications to PD

Gastrointestinal Contraindications

• Inflammatory or ischemic bowel disease increases risk of transmural contamination by enteric organisms, making HD preferable 1, 5
• Frequent episodes of diverticulitis significantly increase peritonitis risk and represent a strong relative contraindication to PD 1, 5
• Presence of colostomy or ileostomy requires careful individualized assessment but is not an absolute contraindication 1

Anatomical and Physical Limitations

• Advanced polycystic kidney disease may restrict intraperitoneal volumes needed for adequate dialysis 5
• Severe lumbo-sacral disk disease may limit tolerance of peritoneal fluid volumes 5
• Recurrent hydrothorax is a contraindication due to fluid management challenges 5
• Morbid obesity presents challenges in catheter placement, wound healing, and achieving adequate dialysis clearance, plus risk of further weight gain from dialysate glucose absorption 1, 5

Respiratory Contraindications

• Advanced lung disease may limit tolerance of peritoneal fluid volumes due to increased intra-abdominal pressure affecting diaphragmatic excursion 5

Infection Risk Factors

• Abdominal wall or skin infections increase risk of catheter site contamination and peritoneal cavity infection 1, 5

Nutritional Considerations

• Severe malnutrition is a relative contraindication due to compromised wound healing, inability to tolerate peritoneal protein losses, and potential inability to comply with self-dialysis regimen 1, 5

Indications for Switching from PD to HD

The decision to transfer from PD to HD should be based on clinical assessment, inability to reach adequacy targets, and patient wishes, not arbitrary time limits 1

Mandatory Indications

• Consistent failure to achieve target Kt/Vurea and creatinine clearance despite optimal prescription adjustments and confirmed compliance 1, 5
• Inadequate solute transport or fluid removal identified through peritoneal equilibration testing (PET) 1, 5
• Unacceptably frequent peritonitis or other PD-related complications 1, 5
• Development of technical/mechanical catheter problems that cannot be resolved 1, 5

Relative Indications

• Unmanageably severe hypertriglyceridemia related to glucose absorption from dialysate 1, 5
• Severe malnutrition resistant to aggressive management 1, 5
• High transporters experiencing poor ultrafiltration and excessive protein losses 1, 5

Infection Considerations

• PD may reduce the number of bacteraemia/bloodstream infection episodes compared to HD (RR 0.44,95% CI 0.27 to 0.71), likely due to avoidance of vascular access-related infections 2
• HD patients using central venous catheters face particularly high infection-related mortality and morbidity 3
• Peritonitis rates have significantly decreased over time but technique failure from infectious complications remains a concern with PD 3

Quality of Life and Patient Autonomy

• Home dialysis modalities (including PD) are associated with greater patient autonomy and treatment satisfaction compared to in-center HD 1
• Patient satisfaction may be higher with PD, allowing more flexibility in daily activities 3
• Choice among available modalities is preference-sensitive, requiring consideration of quality of life, life goals, clinical characteristics, family/care-partner support, and living environment 1
• Employment outcomes show uncertain differences between modalities (RR 0.83,95% CI 0.20 to 3.43) 2

Cost Considerations

• PD costs are significantly lower than in-center HD costs in most healthcare systems 3
• The bundled reimbursement system may incentivize increased PD utilization 3

Special Clinical Scenarios

Acute Hyperammonaemia (Paediatric)

• Intermittent HD and continuous kidney replacement therapy (CKRT) have proved more efficacious than PD for treating hyperammonaemia 1
• PD shows limited efficacy in reducing ammonia levels, with initial reduction followed by plateau 1
• The decision should be made jointly by multidisciplinary teams considering equipment availability, patient condition, ammonia trends, and patient size 1

Common Pitfalls to Avoid

• Ignoring peritoneal transport characteristics (not performing or considering PET results) can lead to inadequate dialysis prescription 5
• Failing to educate patients about both modalities before dialysis initiation limits informed decision-making 3
• Assuming PD is contraindicated in all patients with ostomies or obesity without individual assessment 1
• Not monitoring for declining peritoneal membrane function over time, missing the window for planned transition to HD 1
• Calculating Kt/V using actual body weight in malnourished patients, which may falsely suggest adequate dialysis 1

Decision Algorithm for Modality Selection

1. Assess for absolute contraindications: Active inflammatory bowel disease, frequent diverticulitis, recurrent hydrothorax, or inability to perform self-care 1, 5

2. Evaluate relative contraindications: Severe malnutrition, morbid obesity, advanced lung disease, severe lumbo-sacral disease, or extensive polycystic kidneys 1, 5

3. Consider clinical advantages: If significant residual kidney function exists, PD may offer preservation benefits 2; if vascular access is problematic or patient has cardiac instability, PD may be preferable 4

4. Prioritize patient preference: When no strong clinical contraindications exist, patient autonomy and lifestyle considerations should drive the decision 1

5. Plan for monitoring: Establish clear adequacy targets (Kt/Vurea and creatinine clearance) and peritoneal transport assessment schedule 1

6. Prepare for potential modality change: Discuss that technique failure occurs over time with PD, and transition to HD may eventually be necessary 4, 3