Chronic kidney disease (CKD) is a condition where, over time, the kidneys become damaged, leaving them unable to filter waste and excess fluid. Normal, healthy kidneys expel these unwanted products through the urine, but as impaired kidneys can’t do their job properly, fluid and waste remain in the body, leading to dangerous complications such as anemia or a weakened immune system.
37 million Americans are affected by CKD, and this number continues to grow worldwide.
Stages of the disease
Chronic kidney disease progresses slowly. Its development is categorized into 5 stages: Stage 1 represents the least amount of kidney damage, and stage 5 represents near or complete kidney failure. Each stage is indicated by a marker called an estimated glomerular filtration rate (eGFR), which measures the kidneys’ ability to filter waste from the blood. A higher eGFR signifies higher kidney function.
Here are the 5 stages of chronic kidney disease, broken down:
Stage 1
In stage 1, the kidneys are damaged but still operating normally. Kidney damage at this stage is diagnosed by key signs, like the presence of protein in the urine. The eGFR at this stage is 90 percent or greater.
Progression of stage 1 chronic kidney disease can be slowed through lifestyle changes such as exercising daily, quitting smoking, eating well, and, importantly, controlling blood pressure. It’s crucial to make these lifestyle changes early on, as the disease is much more difficult to manage at later stages.
Stage 2
Stage 2 is similar to stage 1 in that the kidneys are still functioning somewhat properly, at an eGFR of between 60 and 89 percent. However, more signs of damage can be observed at this stage.
Stage 3
At stage 3 (eGFR between 30 and 59), loss of kidney function is more apparent and symptoms are more likely to be present. Typically, stage 3 consists of two sub-stages: stage 3a and 3b. At stage 3a, the eGFR percentage is between 45 and 59, while at stage 3b it has decreased to between 30 and 44.
Physical symptoms of stage 3 chronic kidney disease may include back pain, frequent urination, and swelling of the hands and feet.
Stage 4
Stage 4 indicates advanced kidney damage. At this stage, kidney failure is not far off, and preparations must be made for the inevitable. The eGFR at stage 4 is between 15 and 29 percent.
Symptoms in this stage may be the same as in the prior stage (with the possible addition of nausea, vomiting, and loss of appetite), but health complications will likely arise. These include anemia, heart disease, bone disease, and high blood pressure.
Stage 5
Stage 5 is the final stage of chronic kidney disease, with a eGFR of less than 15. At this stage, kidney failure is very near or has already set in. New symptoms may occur in addition to those of stages 3 and 4: weakness, fatigue, shortness of breath, worsening swelling, loss of appetite, nausea/vomiting and metallic taste in mouth.
Stage 5 kidney disease is the stage where the kidneys no longer function enough to sustain life and the initiation of therapies are needed, which is either a kidney transplant or dialysis. You’ll need to have a thorough discussion with your nephrologist to discuss treatment options and how to proceed.
Written by Natan Rosenfeld