What’s the Life Expectancy for Complement 3 Glomerulopathy—And How Does It Affect Quality of Life?

Complement 3 glomerulopathy (C3G) is a group of rare kidney diseases caused by an overactive immune system. With C3G, the body produces too much protein, leading to kidney damage. C3G progression and life expectancy vary from person to person: age, kidney function and general health may play a role.

Whether due to genetics, autoimmune issues, or other factors, people with C3G have an overactive complement system (part of the immune system). This dysfunctional complement system breaks down too many infection-fighting proteins, and these protein pieces build up in the kidneys. This causes damage to the glomeruli, or filtration systems of the kidneys, leading to kidney problems.

These kidney problems get worse over time. Up to half of adults with C3G may develop end-stage renal disease (ESRD) within 10 years of their initial diagnosis. ESRD, also called permanent kidney failure, is a serious, life-threatening condition that occurs when the kidneys cannot meet the body’s needs.

The type of C3G you have may affect your risk of developing ESRD. There are two main types:

• Dense deposit disease (DDD): This type is characterized by long, ribbon-shaped protein deposits in the kidneys. People with DDD are usually diagnosed as children or adolescents. People with DDD may be at increased risk of certain C3G complications, including vision problems and problems with the distribution of fat in the body.
• C3 glomerulonephritis (C3GN): People with C3GN have small clumps of protein in their kidneys and are usually diagnosed in adulthood. They are at increased risk of ESRD compared to those with DDD. However, the rate of kidney damage and failure is generally slower in people with C3GN than in those with DDD.

Age also seems to play a role. Some research suggests that up to 70% of children with C3G progress to ESRD, compared to about 30 to 50% of adults.

Patients are also at higher risk of ESRD if they have poorer kidney filtration function and more protein in their urine at the time of diagnosis.

C3G is a very rare disease and there is no cure. However, many people can expect to live a typical lifespan with C3G, especially when it is well managed with treatment.

About half of all patients with C3G end up suffering from ESRD within a decade of their diagnosis; however, the remaining 50% retain their kidney function longer.

Once a person has ESRD, they may need to undergo dialysis, a process to remove waste from the body, or they may need a kidney transplant. In people who receive a kidney transplant, about half will have their C3G return. Only about 35% of people survive with ESRD for at least 5 years.

People with C3G may experience a decline in their quality of life, particularly if their disease progresses to kidney failure.

It can be difficult to manage the symptoms of C3G, which can include blood in the urine, swelling, frequent infections, and high blood pressure. Fatigue is also a major concern for the majority of C3G patients: a 2024 study found that up to 77% of participants reported needing to sleep during the day due to fatigue.

C3G can also cause:

• Pain or discomfort
• Depression
• Anxiety
• Difficulty completing daily tasks

Although there is no cure for C3G, there are treatment options that can help relieve symptoms and improve prognosis.

Health care providers may prescribe medications for patients to control C3G symptoms like high blood pressure and protein in the urine, which improves kidney function. But certain diet and lifestyle changes can also help.

1. Change your diet

Healthy kidneys generally maintain the body’s fluid balance by regulating levels of sodium and other minerals. But when the kidneys fail to balance sodium levels, it’s important to reduce the amount of sodium in your diet to avoid high blood pressure and other kidney damage.

C3G patients may want to meet with a nutritionist or dietitian to develop a healthy diet to protect their kidney function, which could include:

• Reduced sodium intake
• Limited protein intake
• Less potassium and phosphorus
• Avoid saturated and trans fats

People with C3G or advanced ESRD may need to limit their fluid intake to avoid fluid overload in the body. Talk to your doctor to determine if you need to watch the amount you drink each day.

2. Maintain a healthy weight

Maintaining a healthy weight and avoiding obesity can improve kidney health, as extra body weight can put additional strain on the kidneys.

Work with your healthcare team to determine a healthy weight range for your body, as well as a treatment plan to help you achieve and maintain it. This may include changes to your diet, activity levels, or prescription medications.

3. Avoid tobacco

Smoking is dangerous for kidney health and can accelerate kidney damage. It also increases blood pressure, which can also contribute to kidney problems.

If you currently smoke, talk to your healthcare team about developing a plan to quit smoking.

4. Exercise often

Engaging in regular physical activity can promote a healthy weight and improve kidney health. It can also reduce emotional stress, which can affect kidney health.

Your healthcare team will likely recommend that you incorporate gentle exercises that won’t make your daytime fatigue worse. Consider trying walking, cycling, yoga, or swimming to start.

5. Track your medical appointments

C3G is a chronic illness that requires regular monitoring by your healthcare team. Visit your doctor regularly to check your blood pressure, monitor laboratory values, and treat any complications or side effects of treatment. Take your medications as prescribed to slow the rate of kidney damage caused by C3G.

As C3G progresses, it can lead to worsening high blood pressure, changes in urine, and other problems. Fatigue and mental health symptoms can also affect your quality of life.

A team of healthcare professionals can help you find lifestyle changes or medications that will help manage these symptoms and slow kidney damage. This may include exercising and eating healthily, meeting with a support group, and taking breaks throughout the day to avoid overexerting yourself.