Renal Replacement Therapy: What Happens When the Kidneys Fail?

The kidneys perform one of the body's most essential functions, quietly working day and night. The kidneys maintain internal balance with remarkable precision - removing metabolic waste, regulating fluid status, maintaining electrolyte balance, supporting bone and mineral metabolism, and producing hormones such as erythropoietin and active vitamin D. When kidney function declines beyond recovery, these processes cannot be sustained. At that stage, renal replacement therapy (RRT) becomes necessary. It takes over what the kidneys can no longer do. Generally, most patients do not have a clear understanding of what the RRT options entail or of the day-to-day realities of living with each one.

The three established options for renal replacement therapy are: 

• Hemodialysis 
• Peritoneal dialysis 
• Kidney transplantation 

Among the available options, kidney transplantation is widely regarded as the optimal form of renal replacement therapy because it restores most aspects of normal kidney function. A successful transplant not only removes waste products and excess fluid, but also re-establishes endocrine functions such as erythropoietin production and vitamin D metabolism and gives you better bone health and metabolic stability.

In contrast dialysis therapies (hemodialysis and peritoneal dialysis) primarily replace only the excretory functions of the kidney, that is, the removal of toxins and excess fluid. They do not fully replicate the complex hormonal and metabolic roles of a functioning kidney.

The choice of renal replacement therapy depends on clinical factors, patient preferences, and access to resources including access to a suitable donor, and is best made through a detailed discussion between the patient and the treating nephrology team. At KIMS Hospitals, Electronic City, Bengaluru if you or your loved ones are approaching end stage renal disease we will guide you through each treatment option in detail with decisions made collaboratively (all this to ensure that approach we chose together aligns with your medical needs, preferences and lifestyle).

Understanding the Options

1. Hemodialysis

Hemodialysis removes waste products and excess fluid by circulating blood through an external filter (dialyser) and returning it to the body

Treatment is typically performed:

• 3 times per week 
• 3-4 hours per session 
• Usually in a dialysis centre 

A vascular access (most commonly an arteriovenous fistula) must be created in advance and allowed to mature.

Advantages

They are:

• Efficient and predictable clearance of toxins 
• Delivered under medical supervision 
• Suitable for patients with multiple comorbidities or limited home support.

Limitations

They are:

• Fixed schedule with significant time commitment 
• Dietary and fluid restrictions (potassium, phosphate and sodium) 
• Intradialytic symptoms and post-dialysis fatigue in some patients 
• Cardiovascular stress due to intermittent fluid shifts.

2. Peritoneal Dialysis

Peritoneal dialysis uses the peritoneal membrane (a lining of your abdominal cavity) as a natural semipermeable filter. A catheter placed surgically into the peritoneal cavity allows dialysis fluid to be instilled, dwelled, and drained. Waste and fluid pass from blood vessels into the dialysate during the dwell period. 

Two main forms are:

• CAPD (Continuous Ambulatory Peritoneal Dialysis): CAPD involves manual fluid exchanges performed by the patient, typically three to four times a day. Each exchange takes about 20–30 minutes. It includes draining the used fluid and instilling fresh dialysis solution. Between exchanges (during what is known as the dwell period) the fluid remains in the abdomen while dialysis continues. During this time patients are free to move around and carry on with their usual daily activities without being confined to a machine or a specific location.
• APD (Automated Peritoneal Dialysis) uses an overnight machine, leaving patients exchange-free during the day. Both are done at home.

Advantages

• Greater independence and flexibility 
• Better preservation of residual kidney function 
• More stable hemodynamics (gentler on the heart) 
• Fewer dietary restrictions than hemodialysis. 

Limitations

They are:

• Requires strict adherence to sterile technique 
• Risk of peritonitis, which remains the major complication 
• Daily responsibility for exchanges 
• Not suitable for all patients (like after abdominal surgeries or social constraints).

3. Kidney Transplantation

Kidney transplantation is the only treatment modality that restores kidney function rather than partially substituting for it. A donor kidney is surgically implanted and connected to the recipient’s blood vessels and bladder. Native kidneys are usually left in place.

Why is it the preferred option (when feasible):

• Superior quality of life 
• Freedom from dialysis 
• Fewer dietary and fluid restrictions 
• Better long-term survival compared to dialysis 

Types of transplants:

Living donor transplantation

• Best outcomes overall 
• Immediate graft function in most cases 
• Longer graft survival 
• Can often be performed pre-emptively (before dialysis begins) 

Deceased donor transplantation

• Allocated through state registries 
• Waiting times vary 
• Dialysis is needed while awaiting transplant 

Considerations

They are:

• Need of lifelong immunosuppressive therapy 
• Risk of infection, malignancy, and metabolic complications 
• Not all patients are suitable candidates 

How Do We Choose the Right Option?

The decision is individualized and guided by a few attributes. They are:

• Age 
• Cardiovascular status 
• Residual kidney function 
• Comorbid conditions like diabetes or hypertension
• Lifestyle & occupation 
• Home environment and support system 
• Access to a living donor 

For eligible patients, transplantation should always be considered early, ideally before dialysis becomes necessary.

For others, the choice between hemodialysis and peritoneal dialysis is collaborative. Each has distinct advantages, and the “right” choice is the one that aligns with the patient’s medical condition and daily life. At KIMS Hospitals, Electronic City, we ensure that patients and their families clearly understand what each modality involves including the practical demands, benefits, and potential risks so they are able to make a well-informed decision about their renal replacement therapy.

Conclusion

Renal failure is a life-altering diagnosis but it is manageable with timely & appropriate intervention. Hemodialysis, peritoneal dialysis and transplantation each offer a viable path forward. The key lies in:

• Early planning 
• Clear understanding of options 
• Informed, shared decision-making .

At KIMS Hospitals, Electronic City, patients approaching advanced kidney disease are counselled early, allowing time for access creation, modality selection, or transplant evaluation, well before urgent intervention becomes necessary.

FAQs 

Which is better: hemodialysis or peritoneal dialysis?

Neither is universally superior. Outcomes are broadly comparable in many patient groups though individual factors especially cardiovascular status and lifestyle play a major role in determining the optimal choice.

Can I continue working while on dialysis?

Yes many patients can work, particularly those on automated peritoneal dialysis. Hemodialysis requires more schedule adjustment but can still be compatible with work.

Who is eligible for a kidney transplant?

Most patients with end stage kidney disease are evaluated. Contraindications are active infection, uncontrolled malignancy, and severe comorbidities that preclude surgery.

How long does a transplanted kidney last?

On average, a transplanted kidney functions for around 10 to 20 years. This can vary widely depending on factors like medication adherence, regular follow-up, overall health, and how well the body accepts the graft.