Chronic dialysis is an ongoing, life-sustaining treatment that takes over the filtering work of your kidneys when they can no longer do it themselves. Unlike a short course of dialysis after an acute injury, chronic dialysis is long-term, typically continuing for the rest of a person’s life unless they receive a kidney transplant. Most people begin when their kidney function drops to roughly 5 to 9 percent of normal, though symptoms and complications sometimes push that timeline earlier.
Why Chronic Dialysis Becomes Necessary
Your kidneys filter waste products, excess fluid, and electrolytes from your blood. When chronic kidney disease progresses to the point where they can only manage a small fraction of that workload, toxins build up and fluid accumulates. This stage is called kidney failure, or end-stage renal disease.
The decision to start dialysis isn’t based on a single lab number. Guidelines from KDIGO recommend initiating treatment when kidney function falls to around 5 to 9 milliliters per minute (normal is about 90 or higher). But if someone develops dangerous complications earlier, such as fluid overload, severe nausea and vomiting that won’t respond to medication, mental fogginess, or inflammation around the heart, dialysis may start sooner. People with diabetes or other conditions that accelerate kidney damage sometimes need to begin while their numbers still look relatively higher.
Hemodialysis: How It Works
Hemodialysis routes your blood through a machine that acts as an external kidney. Blood leaves your body through a needle, passes through a filter called a dialyzer that removes waste and extra fluid, and returns cleaned. A standard in-center schedule is three sessions per week, each lasting about three to four hours, with a minimum session length of two and a half hours. Some people do nocturnal hemodialysis at home, running sessions of six or more hours, six nights a week, which more closely mimics the continuous filtering healthy kidneys provide.
To move enough blood through the machine, you need a reliable point of access in your bloodstream. There are three main options. An arteriovenous fistula (AVF) is created surgically by connecting an artery directly to a vein, usually in the forearm. It needs about six weeks to mature before it can be used, and roughly one in four fistulas never matures properly. An arteriovenous graft uses a synthetic tube to bridge the artery and vein, requiring about two weeks before it’s ready. Central venous catheters, placed in a large vein in the neck or chest, are used when someone needs dialysis urgently while waiting for a fistula or graft to heal.
Peritoneal Dialysis: The Home-Based Option
Peritoneal dialysis uses the lining of your abdominal cavity as the filter instead of a machine. A catheter implanted in your abdomen lets you fill the space with a sterile solution that draws waste and fluid out of the blood vessels in that lining. After a dwell period of several hours, you drain the fluid and replace it with fresh solution. The entire process is called an exchange.
There are two main approaches. Continuous ambulatory peritoneal dialysis (CAPD) is done manually, with three or four exchanges spread throughout the day. You perform each exchange yourself, and no machine is required. Automated peritoneal dialysis (APD) uses a programmable device called a cycler that runs exchanges overnight while you sleep. Some people on APD also keep a fill in the abdomen during the day to extend the filtering time. Both methods let you dialyze at home, which many people prefer for the flexibility it offers.
What a Typical Week Looks Like
If you’re on standard in-center hemodialysis, your life revolves around three fixed appointments, usually Monday-Wednesday-Friday or Tuesday-Thursday-Saturday. Each visit takes roughly four to five hours including setup and needle placement. Travel time, waiting, and post-session fatigue can effectively consume most of those days. Many people describe feeling washed out for hours after a session as their body adjusts to the rapid fluid shifts.
Diet plays a major role between sessions. Most hemodialysis patients are advised to keep phosphorus under 800 milligrams per day, potassium under 3 grams per day, and salt under 2.5 grams per day. Fluid limits vary but are often tight, since your kidneys can no longer remove excess water on their own. These restrictions can feel extreme. Phosphorus hides in dairy, processed foods, and many protein sources, while potassium is high in bananas, potatoes, and tomatoes. Balancing adequate protein intake (which you need more of on dialysis) against these restrictions is one of the harder practical challenges.
Common Complications
Cardiovascular problems are the leading cause of death among people on chronic dialysis. Between 70 and 80 percent of dialysis patients develop thickening of the heart muscle, a condition that strains the heart and raises the risk of heart failure. Fluid overload between sessions independently doubles the risk of death, even after accounting for high blood pressure and other factors. Heart failure and heart attacks together are the second most common cardiovascular cause of death in this population.
Infection is another persistent risk, particularly for people using catheters rather than fistulas. Access-site infections can enter the bloodstream quickly and become serious. Bone and mineral disorders develop as dialysis struggles to fully replace the kidney’s role in regulating calcium and phosphorus. Over time, this can weaken bones and cause calcium to deposit in blood vessels.
Fatigue, Depression, and Daily Life
Chronic dialysis takes a significant psychological toll. Studies of hemodialysis patients find fatigue in about 52 percent of the population, and nearly 70 percent report sleep disorders. Depression symptoms appear in roughly 35 percent of dialysis patients, and among those who are fatigued, depression rates climb to about 66 percent. These aren’t minor inconveniences. Persistent exhaustion and low mood affect work, relationships, and the ability to keep up with the treatment schedule itself.
The quality of life impact is real and measurable. People on dialysis frequently describe cognitive changes: difficulty concentrating, forgetfulness, and a general mental slowness that wasn’t there before. Social isolation is common, partly because of the time commitment and partly because dietary restrictions make eating with others complicated. Recognizing these effects as part of the disease, not personal weakness, matters.
How Dialysis Adequacy Is Measured
Your care team tracks whether each session is filtering enough waste using a calculation called Kt/V, which essentially measures how thoroughly the blood was cleaned relative to your body size. For hemodialysis, the target is a Kt/V of 1.2 or higher per session. For peritoneal dialysis, the target is higher at 1.7, because the filtering happens more gently and continuously. These numbers are checked regularly, and if your dialysis falls below the threshold, your prescription (session length, flow rate, or exchange volume) gets adjusted.
Survival and the Transplant Alternative
Chronic dialysis keeps people alive, but the long-term survival numbers are sobering. According to the most recent data from the U.S. Renal Data System, the five-year survival probability after starting hemodialysis is about 41 percent. For peritoneal dialysis, it’s slightly higher at around 42 to 43 percent. These numbers have barely changed in a decade.
Kidney transplantation, when it’s an option, offers dramatically better outcomes. Transplant recipients have roughly 72 percent lower mortality risk compared to dialysis patients after adjusting for age. At three years post-transplant, only about 6 percent of recipients remain dependent on dialysis, while 100 percent of those who stayed on dialysis obviously remain dependent. The challenge is organ availability: wait times for a deceased-donor kidney average several years in most parts of the United States, and not everyone is a candidate for transplant due to age, other health conditions, or surgical risk.
For those who are candidates, getting on the transplant list as early as possible, ideally before dialysis even starts, gives the best chance at a longer and less restricted life. Living-donor transplants bypass much of the wait and tend to have the best long-term outcomes of all.