Kidney Failure

Stages 3 and 4 are the respective moderate to severe stages of kidney damage; kidney failure is stage 5. Stage 3a is 45-59 eGFR (estimated glomeral function, a somewhat subjective assessment of how well kidneys are functioning) and is stabilized by staying hydrated and controlling blood pressure (if high). Along with this, dietary changes kick in with stages 3b and 4, such as less protein (especially red meat), potassium, and phosphorus. It is important to keep exercising, and good to consult with a dietician with renal experience. It is also good to check medicines and supplements to see if any contribute to decreased kidney function. For example, my opthomologist stated me on AREDS2 last March, which is not recommended for people with CKD because kidneys can't filter the heavy metals and fat-based vitamins as well. https://www.kidneyfund.org/all-about-kidneys/stages-kidney-disease

Stage 3 and stage 4 kidney failure refer to how well the kidneys are filtering waste, based on something called the GFR (glomerular filtration rate). The lower the GFR, the worse the kidney function.

Stage 3 Chronic Kidney Disease (CKD):

GFR ~30–59.

Kidneys are moderately damaged.

Many people have few or no symptoms at this stage.

Common issues that start appearing:

Fatigue.

Swelling in legs.

Higher blood pressure.

Early changes in lab work (anemia, abnormal electrolytes).

With good medical care, people often live many years in stage 3 without progressing.

Stage 4 Chronic Kidney Disease

GFR ~15–29.

Kidneys are severely damaged.

Symptoms become more noticeable:

More fatigue.

Swelling.

Nausea or poor appetite.

Itching.

Worsening blood pressure.

This stage is when doctors usually prepare for stage 5, which is kidney failure needing dialysis or a transplant.

Important Note

“Kidney failure” technically means stage 5 (GFR < 15), but many people casually use the term to refer to stage 4 because it’s getting close.

I might add, from my experience my creatinine is 2.66 and my eGFR is 19. I feel great, and none of the symptoms mentioned by @tommy901. Not to say these are generalized symptoms. Some people feel these symptoms much earlier. It depends on your specific disease. All of my blood work is perfect except for creatinine. I recently went to Italy for 2 weeks, felt great. My BP is normal without meds. I'm in the range to be evaluated for a transplant and I'll find out next week if that's the case. I do not have to watch potassium or phosphorus, they are in normal range. I do not have swelling or itching and have lots of energy. I just went to our YMCA to join to get more exercise. I follow my Nephrologist recommendations.
I guess it's important to point out, many people with late 4th stage kidney disease live normal lives with little or no symptoms. I have a first cousin who's lived with eGFR 20 for over 10 years. She said she would not know she had kidney disease if not for the labs and bloodwork.

My point is, it is scary to say these things without personalized experiences. Everyone is different. I'm on a forum of kidney patients. Some of the posters are at stage 5 and are not on dialysis and feel good. Much depends on how you feel. There are remarks from European patients who say their Nephrologist would not put a patient on dialysis if they felt good, had stable BP, normal urination, even in stage 5. A word to those who are in stage 3, wait and see how your symptoms play out. In my opinion, it's not necessary to scare everyone when everyone is different. No offense @tommy901, just sharing my knowledge.

When I first found out I had CKD , I thot I was going to hv to be on dialysis because my EGFR was 16 but by eating more vegs. & exercising more my numbers for eGfr have increased . Kudos to you for stating that as long as you feel good you can be a productive person with CKD. & don’t feeling like your life is coming to a halt!! Thank you !!