Living With One Kidney: Risks, Care, and Life Expectancy | Dr. Mahdi Ghazi

Living with one kidney does not mean a limited quality of life or a shorter lifespan. A solitary kidney may result from a congenital defect, certain kidney diseases, injury, or surgery, but the body has a strong ability to adapt to this situation.

In people with one kidney, the size and function of the remaining kidney increase, allowing it to continue near-normal function even with a single kidney and maintain hemodynamic balance. Even so, the remaining kidney needs informed care.

In general, most people with one kidney live long, healthy lives, provided they follow ongoing monitoring and kidney-protection principles. In the rest of this guide, we review the causes, consequences, and most important care strategies in a comprehensive, clinically focused way and answer common concerns about living with one kidney. Stay with us.

Is one kidney enough for a normal life?

Yes. In most cases, one healthy kidney is fully enough for a normal, active, long-term life. Many people around the world live with one kidney without serious limits in daily activity or a noticeable reduction in lifespan.

The reason for this remarkable adjustment is the body's ability to adapt to new conditions. When one kidney is absent, the remaining kidney gradually becomes larger and more efficient; in medicine, this process is called compensatory hypertrophy. This adaptation effectively increases the function of the remaining kidney.

Scientific studies show that after this adaptation, the remaining kidney can provide about 65% to 75% of the total filtration capacity of two healthy kidneys. For this reason, in most people, blood filtration and the body's fluid balance are maintained properly (PubMed).

On this basis, large studies have shown that lifespan and life expectancy in people who have one healthy kidney are usually not meaningfully different from the general population, especially when recommended care and a healthy lifestyle are followed.

Life Expectancy and Lifespan Statistics for People With a Solitary Kidney

Scientific evidence shows that in most people with a solitary kidney, especially healthy living kidney donors, lifespan and life expectancy are not meaningfully different from the general population and may even be better. As the National Kidney Foundation states in its materials, if the remaining kidney is healthy, lifespan is not affected.

Long-term studies, such as the Swedish study by Fehrman-Ekholm et al, have also shown that kidney donors, even after 20 years of follow-up or more, did not have a meaningful increase in mortality compared with ordinary individuals and in some cases had better survival.

Overall, with regular care and yearly monitoring, including blood pressure, eGFR, and albuminuria testing, a long life with good quality is fully expected.

Causes of Having One Kidney

Medically, having one kidney can be congenital or acquired. It is also important to distinguish between two key concepts:

• Anatomic solitary kidney: the person truly has only one kidney.

• Functional solitary kidney: two kidneys are present, but only one works effectively.

This distinction is necessary for a more accurate understanding of the types of solitary kidney. The table below briefly compares the most important congenital and acquired situations:

Below, we review each situation in more detail.

Renal Agenesis

Renal agenesis is one of the main causes of having one kidney and is considered a congenital kidney defect. In this condition, during fetal development, the metanephric tissue, the early structure that forms the kidney, does not form at all on one side. As a result, the person is born with a congenital solitary kidney.

Its frequency is about 1 in 2,000 births, and it is more common in boys. Most cases of renal agenesis have no symptoms and are usually found incidentally during pregnancy ultrasound or later imaging. Many people remain unaware of this condition for years and live normal lives.

Renal Dysplasia

In renal dysplasia, a person is born with two kidneys, but one of them does not function adequately because its tissue structure is abnormal. In practical terms, that kidney becomes a nonfunctioning kidney.

Over time, the abnormal kidney undergoes atrophy and kidney shrinkage occurs; sometimes it becomes difficult to see on later imaging. This condition is initially considered a functional solitary kidney, but in advanced cases it may functionally resemble an anatomic solitary kidney.

Total Nephrectomy Surgery and Kidney Donation

Nephrectomy means surgical removal of a kidney. In a total nephrectomy, one kidney is removed completely, and the person becomes anatomically solitary-kidney. The most important reasons include:

• Severe traumatic injury;

• Kidney cancer;

• Chronic obstruction or severe infection that does not respond to treatment;

• Kidney donation to a patient who needs a transplant.

Possible Consequences of Having One Kidney

Having one healthy kidney usually does not prevent a normal, active life. The prognosis for people who have only one healthy kidney with adequate function is generally very good. Most of these people spend many years without any significant problem, and among them serious complications are uncommon.

However, because these individuals do not have another kidney, they are more vulnerable to factors such as high blood pressure, severe infections, direct kidney injury, or certain underlying diseases. If the remaining kidney is damaged, there is no second kidney to compensate. Therefore, to prevent possible injury, regular monitoring and care need to be more precise.

Below, we review the most important potential consequences of living with one kidney in more detail.

Complications

In most people, living with one kidney is not associated with serious complications and does not have a major effect on quality of life or lifespan. If the remaining kidney is healthy, most people live normally. However, because this kidney alone carries the full workload of filtering the blood, a process called compensatory hyperfiltration, some changes may occur. These are usually mild and controllable with regular monitoring.

The most common possible complications are:

• High blood pressure: This is the most common possible consequence. Blood pressure may be slightly higher than normal, but in most cases it is mild and can be managed well with salt control, lifestyle changes, and medication when needed.

• Protein in the urine (proteinuria or albuminuria): Because of greater pressure on the kidney's filtering units, the glomeruli, a small amount of protein may enter the urine. This is often mild and, if detected early, can be controlled with appropriate medication.

• Mild reduction in kidney function: In some people, the glomerular filtration rate, or GFR, may decrease slightly over the years. This decline is usually slow and has no serious effect on overall health, especially if blood pressure and lifestyle are managed well.

• Possible pregnancy-related complications: According to research published in Pediatric Nephrology, the risk of gestational hypertension in women with one kidney has been reported to be about 2.4 to 2.5 times higher than in the general population. For this reason, pre-pregnancy counseling and careful monitoring during pregnancy are recommended.

These complications are not common in people with a healthy kidney and may never occur; many people with a solitary kidney never experience any of these problems.

Vulnerability of People With One Kidney to Risks

Most people with one healthy kidney live normal lives, but because there is no backup organ, any possible injury can have more serious consequences. Factors that are almost harmless for people with two kidneys require more care and caution in people with a solitary kidney. Following a few simple principles can reduce risks as much as possible.

1. Use caution with nonsteroidal anti-inflammatory drugs (NSAIDs)

Medicines such as ibuprofen, naproxen, and high-dose aspirin can reduce kidney blood flow and may lead to kidney injury over the long term. If you need pain medicine, consult your doctor.

2. Adjust medication doses based on the function of the remaining kidney

Your doctor should know that you have one kidney so the doses of certain medicines, including some antibiotics, heart medicines, or diabetes medicines, can be adjusted according to your GFR and not place extra strain on the remaining kidney.

3. Use caution with contrast imaging

Contrast agents used in CT scans or MRI may be toxic to the remaining kidney. Before these tests, it is essential to tell your doctor and make sure your body is adequately hydrated.

4. Avoid high-impact sports

Sports with a risk of direct blows to the back or abdomen, such as boxing, wrestling, or professional football, can increase the risk of injury to the remaining kidney. If you take part in these activities, using a dedicated sports protector is recommended, although it does not remove the risk completely.

Will I need dialysis in the future?

If the remaining kidney is healthy and regular care is maintained, the chance of needing dialysis is very low. Most people never reach complete kidney failure, or ESRD, and if function declines, it is usually mild, gradual, and occurs over years, without affecting quality of life or lifespan.

Factors that increase risk:

• High blood pressure or uncontrolled diabetes;

• Repeated infections or direct kidney injuries;

• Long-term use of medicines that can harm the kidney, such as NSAIDs;

• Obesity and an unhealthy diet;

• Lack of regular monitoring of kidney function and proteinuria-related tests.

If these factors are controlled, the chance of needing dialysis is low. Dialysis becomes necessary only when the remaining kidney stops working completely, which does not happen in most healthy people with a solitary kidney. With regular care, an appropriate diet, and avoidance of harmful factors, it is possible to live for years without fear of kidney failure.

Ways to Care for the Kidney

Now that you understand the physiology, causes, and consequences of having one kidney, it is time to focus on practical ways to protect the remaining kidney. These measures are simple, scientific steps similar to general kidney-health recommendations for people with two kidneys.

Below, we review nutrition, exercise and lifestyle, and medical monitoring so you can preserve long-term kidney function and prevent possible complications.

1. Nutrition Management

Most people living with one kidney do not need a special, restrictive diet and can follow a balanced diet similar to that of people with two healthy kidneys. The focus should be on healthy habits that reduce strain on the remaining kidney:

• Salt: Limit salt intake to help control blood pressure and reduce glomerular workload. A maximum of 1 teaspoon per day is recommended.

• Protein: Moderate intake is enough. Avoid high-protein diets, such as intense bodybuilding diets, but severe protein restriction is not recommended either and is needed only if proteinuria is present or your doctor advises it.

• Fluids: Stay hydrated so waste products are filtered and removed more easily and the risk of kidney stones is reduced. Pale yellow or clear urine is a sign that water intake is adequate.

• Grapefruit: If you have a transplanted kidney, avoid grapefruit or grapefruit juice so it does not interfere with immunosuppressive medicines.

2. Exercise and Lifestyle

Regular exercise helps heart health, weight control, and reducing strain on the kidney:

• Physical activity: Do at least 150 minutes per week of moderate activity, such as brisk walking, cycling, swimming, or gardening, and avoid high-impact sports.

• Weight management: Keep your weight in a healthy range so blood pressure and kidney workload do not increase.

3. Medical Monitoring: Periodic Tests

The most important part of care is regular monitoring so any change in kidney function is identified and managed on time:

• Annual checkup: See a primary care doctor or nephrologist. If high blood pressure, a lower eGFR, or protein in the urine appears, the follow-up interval should be shorter.

• eGFR: Estimated glomerular filtration rate is calculated from the blood serum creatinine level while taking age, sex, and other factors into account, and it is the main indicator for assessing kidney function.

• uACR: The urine albumin-to-creatinine ratio is used for early detection of proteinuria or albuminuria, which can be a sign that kidney injury is beginning.

• Blood pressure: Monitor it at least once a year and control it with appropriate medicines if it is high, because people with a solitary kidney are at higher long-term risk of hypertension.

With these checkups and care measures, you can be confident that the remaining kidney is healthy and under observation, and that any problem will be managed early.

When should I see a doctor?

In addition to an annual checkup that includes eGFR, uACR, and blood pressure, recognizing warning symptoms is very important. Any of these symptoms may be a sign of a problem with the function of the remaining kidney, and if you notice them, you should see a doctor. Early diagnosis often makes the problem easier to manage.

Warning signs that require prompt medical attention:

• Swelling of the limbs (edema): Sudden or persistent swelling in the legs, ankles, hands, or face.

• Bloody urine (hematuria): Visible blood or a change in urine color to pink, red, or brown.

• Cloudy urine: Dark, foamy, or cloudy urine, which may be a sign of infection or proteinuria.

• Uncontrolled blood pressure: Very high blood pressure that is not controlled with usual medicines.

• Sudden change in urine volume: A marked decrease, or oliguria, or an unusual increase in urine volume.

These symptoms may be caused by infection, injury, high blood pressure, or reduced kidney function and should not be ignored.

eGFR-based warning, according to the CKD standards:

• eGFR less than 60 ml/min/1.73 m² for at least 3 months: reduced kidney function at stage G3. This requires closer follow-up, tighter blood pressure control, and more frequent checkups.

• eGFR less than 30 ml/min/1.73 m²: advanced kidney failure stage, G4 to G5, and usually requires urgent referral to a nephrologist or urologist for treatment management or preparation for next steps.
  Even a mild decrease in eGFR in people with a solitary kidney should be taken seriously because the safety margin is smaller and unnecessary risk should be avoided.

If you notice any of these symptoms or test results, do not wait until your next checkup; contact your doctor promptly. Timely action can make a meaningful difference in the course of control and treatment.

Do I need a kidney transplant?

No. In most cases, a kidney transplant is not needed. One healthy kidney can provide enough function for a long life with good quality. Many people with a solitary kidney, whether congenital or after donation or nephrectomy, live completely normal lives and never reach a stage where dialysis or transplant is needed.

On the other hand, kidney transplantation is major surgery and carries significant complications:

• Lifelong need for immunosuppressive medicines, with risk of infection and side effects.

• Risk of transplant rejection even with immune medicines.

• Long recovery period and careful lifelong monitoring.

For someone whose existing kidney is still working, transplant is unnecessary and may even be risky. Transplant is a treatment option only when the remaining kidney has completely failed. Therefore, as long as your kidney is healthy, the best and safest path is to care for that remaining kidney.

Summary and 5 Key Tips for Kidney Care

Having one kidney may be congenital, such as agenesis or dysplasia, or acquired, such as kidney removal because of injury, cancer, or donation. The good news is that the function of one healthy kidney is enough for ordinary life and most people live normal, long lives with appropriate care; therefore, you will not need dialysis or transplant.

The remaining kidney has to do more work, so following a few practical tips can reduce the risk of possible complications such as high blood pressure, proteinuria, or gradual loss of function:

1. Keep your blood pressure below 130/80 and monitor it regularly.

2. Avoid self-directed use of NSAIDs, including pain relievers such as ibuprofen and naproxen.

3. Drink enough water each day so your urine is pale yellow.

4. Have blood and urine tests at least once a year to check kidney function.

5. During higher-risk activities, protect the remaining kidney from impact.

By following these simple steps, you can protect your kidney health, prevent kidney failure, and continue daily life with confidence. Always consult a nephrologist or urologist if you have questions or concerns.

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