Chronic kidney disease (CKD) eventually leads to end-stage renal disease (ESRD) when the kidneys can no longer sustain life, causing the body to accumulate dangerous levels of waste products, fluid, and electrolytes. Dialysis is a medical treatment that takes over the function of the failing kidneys, filtering the blood to remove these harmful substances and excess fluid. The decision to begin this life-sustaining treatment is complex, balancing objective medical data with a patient’s quality of life and personal preferences.
Key Medical Criteria for Starting
The decision to initiate dialysis is primarily guided by objective laboratory markers reflecting the kidneys’ filtering capacity. The most significant marker is the estimated Glomerular Filtration Rate (eGFR), which indicates how many milliliters of blood the kidneys clean per minute. Healthy function is above 90 mL/min/1.73m², but dialysis is generally considered when the eGFR falls below 15 mL/min/1.73m² (Stage 5 CKD).
While a low eGFR signals kidney failure, the actual target for initiating dialysis in the absence of severe symptoms is often lower, typically falling within the 5 to 10 mL/min/1.73m² range. Studies have shown that starting dialysis prematurely at a higher GFR, such as above 10 mL/min/1.73m², may not offer a survival advantage over a more conservative approach. However, this decision requires close monitoring of other blood abnormalities that signal metabolic failure.
Beyond the eGFR, doctors monitor the buildup of nitrogenous waste products like blood urea nitrogen (BUN) and creatinine. The accumulation of these wastes, known as uremia, causes physical symptoms associated with severe kidney failure. Uncontrolled electrolyte imbalances, such as hyperkalemia (high potassium) or metabolic acidosis (excess acid in the blood), are also reasons to start dialysis immediately, regardless of the GFR number. These medically resistant derangements indicate a body struggling to maintain internal balance.
When Symptoms Dictate the Need
Although laboratory numbers provide a clear benchmark, a patient’s physical experience often becomes the overriding factor for starting treatment. The clinical signs and symptoms of uremia can become intolerable, even if the eGFR is slightly above the typical initiation threshold. One of the most common complaints is severe, persistent fatigue and generalized weakness, which results from the accumulation of toxins and often the presence of anemia.
Another urgent symptom is fluid overload that cannot be managed with diuretic medications. This excess fluid can accumulate in the lungs, a condition called pulmonary edema, which causes severe shortness of breath and difficulty breathing. The accumulation of waste products can also cause intractable nausea, vomiting, and a metallic taste in the mouth, leading to poor nutrition and weight loss.
Neurological complications, collectively known as uremic encephalopathy, can manifest as confusion, decreased mental sharpness, and difficulty concentrating. Other symptoms that severely impact quality of life include persistent, widespread itching (pruritus) and restless legs syndrome. When any of these symptoms become severe, unresponsive to medication, or life-threatening, they become absolute indications for starting dialysis immediately.
Necessary Preparations Before Starting
For patients whose kidney function is steadily declining, preparation for dialysis must begin well in advance of the actual start date. This preparation is centered on establishing a reliable access point for the dialysis machine to filter the blood. The preferred and most durable access for hemodialysis is an Arteriovenous (AV) fistula, which is a surgical connection between an artery and a vein, typically in the arm.
An AV fistula requires several weeks to months after surgery to “mature,” meaning the vein wall thickens and enlarges under the increased pressure to withstand the repeated needle insertions required for dialysis. If an AV fistula is not possible due to poor blood vessels, a vascular surgeon may create an AV graft, which uses a synthetic tube to connect the artery and vein. Planning for access placement should ideally begin when the eGFR is between 15 and 20 mL/min/1.73m² to ensure the access is ready when needed.
If the need for dialysis is sudden or urgent, a temporary hemodialysis catheter is often placed in a large vein in the neck or chest. While this catheter allows for immediate treatment, it carries a higher risk of infection and is not intended for long-term use. Patient education is also a preparation step, providing training on the chosen dialysis modality and outlining necessary dietary and fluid restrictions.
The Shared Decision-Making Process
The ultimate timing of dialysis initiation is a collaborative process between the patient, their family, and the nephrology care team. This process, known as shared decision-making, balances the objective medical evidence with the patient’s personal values and priorities. The doctor presents the clinical data, such as the GFR and electrolyte levels, alongside the prognosis for the patient’s overall condition.
The patient’s role is to communicate how the symptoms are affecting their quality of life, their goals for treatment, and their willingness to accept the burdens of dialysis. For example, a patient may choose to start treatment slightly earlier to alleviate severe fatigue and prevent an emergency hospitalization. Conversely, an asymptomatic patient may elect to defer treatment until the GFR nears the lower end of the threshold, provided they are closely monitored.
This collaborative discussion ensures that the final decision aligns with the individual’s desired lifestyle and comfort. The goal is to initiate dialysis at a time that prevents serious complications from uremia while maximizing the patient’s independence and well-being.