Like the general ESRD population, the prevalent HD population is predominately white (56% white, 37% black, and 5% Asian), with a slightly higher proportion of males (57%).

Diabetes is the most common cause of ESRD, followed by hypertension, glomerulonephritis, and congenital and cystic kidney diseases.

The largest age group of HD patients is between 45 and 64 years. This is similar to the general ESRD population and younger patients are more likely to be on peritoneal dialysis or to receive a kidney transplant.

Cardiovascular disease is the leading cause of death among patients on HD, followed by sepsis.

The average lifespan after commencing dialysis is approximately 8 years in those aged 40 to 44 years, dropping to 4.5 years in those aged 60 to 64 years.²

The probability of death in the first 5 years after starting HD is 63%.³

Among diabetics on HD, this probability rises to 71%.

Dialysis patients over the age of 65 have a mortality rate seven times higher than the general Medicare population. Dialysis patients between the ages of 20 and 64 have a mortality rate eight times higher.

Early nephrology referrals, patient education, and serious consideration of transplant options may be helpful in attenuating the progression to ESRD.

Even with aggressive early medical care, dialysis may become necessary to relieve uremic symptoms, electrolyte imbalances, or fluid accumulation due to declining renal function.

Patients usually develop uremic symptoms and require dialysis initiation, when their estimated glomerular filtration rate (eGFR) falls below 10 mL/min/1.73 m². This varies considerably between patients.

Patients with significant comorbidities, particularly heart failure, may require dialysis initiation at an earlier stage for volume management.

Timing of the initiation of maintenance dialysis requires incorporation of both patient’s uremic symptom burden and eGFR. Studies have shown no difference in outcomes in patients commenced on HD with an average eGFR of 9 mL/min versus 7 mL/min.⁴

Uremic symptoms develop presumably to the accumulation of toxic metabolites that are no longer adequately cleared by the failing kidney.

Acidosis: life-threatening metabolic acidosis with a pH <7.2, not responsive to conservative treatments.

Electrolyte abnormalities: life-threatening hyperkalemia, not responsive to conservative treatment or with associated electrocardiogram (ECG) changes and symptomatic hypercalcemia.

Intoxications: There are a limited number of intoxications for which HD is indicated. It should be considered in patients with deteriorating medical status, those whose measured levels of a substance are indicative of poor outcomes, or those with metabolic derangements (e.g., metabolic acidosis caused by intoxication). Substances that are effectively cleared with dialysis have the following characteristics:

Overload: fluid overload or pulmonary edema not responsive to aggressive diuresis.

Uremia: mental status changes attributable to uremia, uremic pericarditis, or neuropathy, bleeding diatheses, or vomiting associated with uremia.

This form of HD typically involves treatments two to three times per week, with each session averaging between 3 and 4 hours.

Patients receive HD at a dialysis center, where trained staff are able to set up and supervise each treatment. For patients new to HD, this is often the modality of choice to acclimate patients to a supervised and controlled HD session.

The cumulative weekly dose of dialysis is similar to that obtained on intermittent HD. However, dividing the treatments into frequent, shorter treatments may prevent intradialytic complications, particularly hypotension and cramping.

This modality is predominately performed at home, although some in-center locations are able to accommodate the daily treatments.

This modality is associated with increased frequency of vascular complications.

Patients who undergo nocturnal HD at home typically have longer treatment time periods, averaging 6 to 8 hours, performed six nights per week.

This modality does have the added convenience of allowing the patient greater freedom during the day.

Like short daily HD, nocturnal HD is predominately done at home, although in-center locations are available. In-center nocturnal HD typically offers 8-hour treatments, three nights per week.

Fistulas and grafts are vascular conduits that can support a high flow of blood. They are cannulated at each dialysis treatment with two needles—one through which arterial blood is pumped through the dialyzer and the other through which blood is returned into the venous system.

Catheters are placed in a central venous position, typically in the internal jugular location, with flow through separate luminal ports to simulate arterial output and venous return. Specific characteristics of each type of access are described below.

Construction is performed under regional anesthesia by an experienced vascular surgeon and can consist of either a side-to-side anastomosis between an artery and vein or a side-of-artery to end-of-vein anastomosis.

The goal is to provide an access site that can withstand repeated cannulation with large bore needles and can sustain the high blood flow necessary for dialysis. Flow through an AVF averages between 600 and 800 mL/min.

Complications with thrombosis, infection, and vascular steal are lower in comparison to the AVG.

Placement of an AVF requires careful planning, as they can take 3 to 4 months to mature. Furthermore, the construction of an adequate AVF may be impossible if the patient lacks healthy vasculature. In particular, elderly patients or patients with peripheral vascular disease may not have vessels that are amenable to the creation of a fistula.

In lieu of the patient’s native vasculature, a synthetic graft (frequently created from polytetrafluoroethylene) is placed for the arteriovenous connection.

Long-term patency rates are less impressive than those obtained with AVF. However, the AVG does have a few advantages, including a large surface area for cannulation and can be used earlier than an AVF, with a shorter maturation time of 2 to 3 weeks.

Flow rates through an AVG are typically 1000 to 1500 mL/min, with thrombosis occurring at flows less than 600 to 800 mL/min.

The average graft survival rate is approximately 2 years.

Cuffed tunneled dialysis catheters are typically placed in the right internal jugular vein, with a tunneled exit site just below the ipsilateral clavicle.

These can be placed in patients requiring HD who do not yet have a site for a permanent vascular access. However, given variable success with flows, difficulties with recirculation, catheter dysfunction, and significant risk of infection, the catheter should not be used except as an access of last resort.

Diffusion uses the difference in solute concentration between blood and dialysate to drive the movement of small solutes.

Ultrafiltration uses a hydrostatic pressure gradient to move fluid from the blood to the dialysate compartment.