The function of the kidneys is to filter waste products and toxins from the blood. In people with chronic kidney disease (CKD), the kidneys slowly lose their ability to function. Toxins and waste products start to build up in the bloodstream, which can lead to a variety of symptoms. Kidney disease is one of the top 10 leading causes of death in the US.
There are five stages of kidney disease, with stage 5 being the most advanced. Stage 3 kidney disease is considered to be moderate kidney disease. What are the signs of stage 3 kidney disease?
What’s the difference between 3a and 3b kidney disease?
In general, kidney disease is divided into five stages. The stages are defined based on the estimated glomerular filtration rate, or eGFR. This is a measurement of the ability of the kidneys to filter the blood. It’s determined based on a test of a certain waste product called creatinine in the bloodstream. Creatinine should normally be filtered out by the kidneys. When the levels of creatinine are higher, this indicates that the kidneys are not functioning as well. Based on the measured level of creatinine along with certain patient factors, the eGFR can be calculated.
Stage 3 chronic kidney disease is subdivided into two separate stages:
- In chronic kidney disease stage 3a, the eGFR is 45 to 59.
- In stage 3b chronic kidney disease, it’s 30 to 44.
Most doctors consider stage 3a to be a mild to moderate stage of kidney disease. However, stage 3b is considered to be moderate to severe.
Chronic Kidney Disease Stage 3 Symptoms
While those in stage 1 or stage 2 commonly don’t show any symptoms from their kidney disease, stage 3 is often when chronic kidney disease patients first begin to show symptoms. Patients may notice signs like:
- Itchy skin
- Trouble sleeping
- Frequent urination
- Muscle cramps
- Swelling in the feet and hands
Although many patients in stage 3 will start experiencing symptoms such as these, there are also some patients who don’t show any symptoms of their kidney disease even once it’s reached stage 3.
How dangerous is stage 3 kidney disease?
In CKD stage 3, kidney failure has begun to become apparent, and patients often begin to experience symptoms of their kidney disease. Patients with stage 3 kidney disease have a significantly shortened life expectancy. For example, for a 30-year-old man with stage 3a kidney disease, life expectancy is 28.4 years. If he’s in stage 3b, it’s 20.1 years. These numbers indicate a life expectancy significantly shorter than what would be expected in the general population for a man of this age, which is 45 to 50 years.
How do you treat stage 3 kidney disease?
There is no known way to reverse kidney damage that has already occurred. However, if the cause of the kidney disease is addressed, then it’s possible to greatly reduce the chances that the kidney disease will progress beyond stage 3. Diabetes and high blood pressure are the most common causes of chronic kidney disease, and keeping your blood sugar and blood pressure under control is the best way to help protect your kidneys from further damage. This may involve lifestyle changes and taking medications. Keeping alcohol intake within safe limits and addressing any medical issues that can cause kidney damage, like kidney infections or kidney stones, are also important steps to take.
Doctors can also use medications to help control the symptoms of stage 3 kidney disease. Diuretics help the body to get rid of excess fluids, to address symptoms like swelling. Many patients also benefit from taking supplements, like calcium, iron, and vitamin D, to address the problems caused by the loss of kidney function. There is also a medication called finerenone, which can reduce the risk of kidney failure progression.
Some people may need to modify their diets in order to keep their levels of certain minerals within safe limits. For example, the kidneys normally get rid of excess potassium. When your kidneys aren’t functioning properly, you may need to avoid eating foods that contain too much potassium, since your kidneys can’t get rid of the excess potassium as easily.
It’s important to monitor your kidney function, in order to determine whether your kidney disease is progressing beyond stage 3. Regular testing is needed to do this. Some patients visit a laboratory on a regular basis to get their kidney function tests. Others use a home testing service, which allows them to collect samples at their own convenience in the privacy of their homes. The samples are sent to a laboratory, and results are delivered online.
How serious is stage 3 kidney disease?
Although stage 3 is still considered to be a moderate stage of kidney disease, it’s important to take it seriously. In stage 3, kidney disease has already progressed through stage 1 and stage 2. If nothing is done to address the underlying cause, then it’s likely that it will continue to progress into stage 4 and 5. Because of this, even though the symptoms caused by stage 3 kidney disease are usually not too severe, it should be considered a serious disease.
Chronic Kidney Disease Basics. Centers for Disease Control and Prevention. https://www.cdc.gov/kidneydisease/basics.html. Accessed 17 June 2022.
Chronic Kidney Disease (CKD). National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd. Accessed 17 June 2022.
Chronic kidney disease. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/chronic-kidney-disease/symptoms-causes/syc-20354521. Accessed 17 June 2022.
Estimated Glomerular Filtration Rate (eGFR). National Kidney Foundation. https://www.kidney.org/atoz/content/gfr. Accessed 17 June 2022.
Kerendia (finerenone). Bayer. https://www.kerendiahcp.com/?utm_source=google&utm_medium=cpc. Accessed 17 June 2022.
Leading Causes of Death. Centers for Disease Control and Prevention. https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm. Accessed 17 June 2022.
Neild GH. Life expectancy with chronic kidney disease: an educational review. Pediatr Nephrol. 2017; 32(2): 243–248. doi: 10.1007/s00467-016-3383-8.
Slow Progression and Reduce Complications. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/kidney-disease/identify-manage-patients/manage-ckd/slow-progression-reduce-complications. Accessed 17 June 2022.
Treatment – chronic kidney disease. National Health Service. https://www.nhs.uk/conditions/kidney-disease/treatment/. Accessed 17 June 2022.