Complement 3 (C3) glomerulopathy is a rare disease that affects kidney function and can lead to long-term health problems. Some people with C3 glomerulopathy develop severe complications that affect life expectancy. In this article, we’ll cover how C3 glomerulopathy may affect life expectancy and ways people living with the condition may be able to improve their outcomes.
Each person with C3 glomerulopathy is different. Talk to your nephrologist about a personalized treatment plan to control your kidney disease and other steps you can take to live a longer life.
Researchers estimate that in the United States, the prevalence of C3 glomerulopathy is just 1 to 3 cases per one million people. C3 glomerulopathy happens when a part of the immune system called the alternative complement pathway doesn’t function normally. This pathway involves proteins such as C3, which helps — or complements — the immune system to get rid of infections or toxic substances that may harm the body. Your kidneys’ main function is to filter your blood and remove these substances through your urine.
Normally, the kidneys filter out harmful substances through tiny structures called glomeruli. In people with C3 glomerulopathy, the glomeruli become damaged because the alternative complement pathway is too active. As a result, the C3 proteins break into pieces and get trapped in the glomeruli, causing inflammation. The damaged glomeruli can’t filter blood properly, so harmful substances build up and lead to poor kidney function and other problems.
The prognosis (outlook) for C3 glomerulopathy is generally poor. In many cases, the condition will continue to get worse over time and might cause long-term kidney disease. If the disease becomes too severe, the kidneys may stop working completely. This is known as end-stage renal disease (ESRD).
Unfortunately, end-stage kidney disease is a common complication of C3 glomerulopathy — it occurs in up to 50 percent of adults within 10 years of their diagnosis. End-stage kidney disease happens when the glomerular filtration rate, a measure of kidney function, drops below 15 milliliters per minute. If it’s not addressed in time, kidney failure can be fatal.
Although C3 glomerulopathy can decrease life expectancy because of kidney failure, not everyone develops long-term complications. Many people can be successfully treated and live for a long time after diagnosis. Your doctor will discuss your options based on the details of your case and your overall health condition.
To better understand your prognosis, your doctor will consider many factors. Here are some details that may give them more information about your possible disease course.
There are two types of C3 glomerulopathy — dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). These types are based on the pattern of kidney inflammation and damage. However, if you’ve had the disease for a long time, you may have been given a different diagnosis. Until 2013, C3 glomerulopathy was diagnosed as either mesangioproliferative glomerulonephritis or membranoproliferative glomerulonephritis.
Although prognosis may partly depend on the type of C3 glomerulopathy, the results from clinical trials — research studies that test drugs’ safety and effectiveness — have been mixed. In one study, the rate of kidney failure was about twice as high in people with DDD compared to those with C3GN. However, two other large studies found that people with these diseases had a similar chance of kidney failure.
It’s also important to note that people with either type of C3 glomerulopathy might not have kidney problems at all. Knowing what type of disease you have is important — your diagnosis alone can’t predict your prognosis.
C3 glomerulopathy can affect both children and adults, and research suggests that the age at diagnosis can help predict prognosis. Some studies show that adults with C3 glomerulopathy often have more severe kidney problems, such as glomerulosclerosis (scarring in the kidneys’ filtering units). Also, about one-third of adults with C3 glomerulopathy experience acute kidney failure, which is rarely seen in children. Although this suggests that C3 glomerulopathy may be more aggressive in adults, some other studies disagree with these findings.
Regarding sex, a 2023 study found that 71 percent of male children were in the C3GN group, compared with 38 percent for the DDD group.
Your doctor may run laboratory tests to check for abnormalities and monitor the health of your kidneys. The results can give information about your risk of kidney failure. Lab tests look for signs of C3G, including:
Research findings have shown that higher levels of proteinuria and kidney damage are linked to a greater risk of kidney failure. Similarly, research suggests that low hemoglobin levels can predict a poorer outcome for those with C3G. Rates of kidney failure are also higher in people whose blood creatinine levels rise quickly over time, as this reflects a faster decline in eGFR.
By monitoring your lab results, your doctor can better understand your risk of severe health problems. If necessary, your doctor may do a kidney biopsy to confirm the diagnosis and identify the specific type of disease. This involves taking a small tissue sample from your kidney, processing it, and examining it under a microscope. The biopsy helps detect deposits of C3 breakdown products and reveals how and where your kidneys have been damaged.
Because C3G is a rare disease with variable clinical symptoms, it may be difficult to diagnose. However, once diagnosed, different types of treatments for C3 glomerulopathy may improve the outcome of people with the condition. These treatments may aim to improve kidney health, address underlying immune system issues, or extend life in cases of kidney failure.
To improve kidney health, most people with C3 glomerulopathy are treated with a drug that can decrease both proteinuria levels and hypertension (high blood pressure). This may be either an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin-receptor blocker (ARB). If you have high levels of cholesterol in your blood, your doctor may also prescribe medication to lower your cholesterol and reduce your risk of heart disease.
Even with treatment, many people will progress to end-stage kidney disease. If kidney failure does occur, you may require dialysis. This is a medical procedure repeated long term to filter the blood when the kidneys can’t. Once people begin dialysis, they live an average of five to 10 more years, although some live as long as 30 years on dialysis. For people with kidney failure who choose not to undergo dialysis, research shows the median survival ranges from one month to 3.4 years.
Alternatively, if you’re eligible, you may be able to join the waiting list for a kidney transplant to replace damaged kidneys with healthy ones from an organ donor. Although a transplant may help you live a longer life, there’s a chance that C3 glomerulopathy may eventually come back. If this happens, you’ll need additional treatment.
Fortunately, recent research has paved the way for more effective treatment options for C3 glomerulopathy. These include immunosuppressive medications, which lower the activity of the immune system. Clinical trials have shown that immunosuppressive therapy using corticosteroids with the drug mycophenolate mofetil (CellCept, Myfortic, Myhibbin) may prevent kidney disease from getting worse.
Researchers are studying additional medications for their safety and effectiveness in treating C3 glomerulopathy by targeting the complement system. For example, the C5a receptor inhibitor avacopan (Tavneos) is being evaluated as a potential treatment for C3 glomerulopathy. Another promising option is eculizumab (Soliris), a monoclonal antibody that modifies complement protein C5 and may improve outcomes. Although eculizumab has been shown to reduce proteinuria and stabilize kidney function, it doesn’t necessarily prevent kidney disease progression.
A drug called iptacopan (Fabhalta), which also modifies complement proteins, recently completed its phase 3 (late-stage) clinical trial. The results showed that iptacopan reduced proteinuria by 35.1 percent in participants who took it alongside supportive care. A reduction in proteinuria can significantly delay kidney failure. The findings also indicated secondary improvements for people with kidney disease, including improved eGFR. Researchers will continue to explore the effectiveness of iptacopan as a treatment for C3 glomerulopathy.
Zaltenibart, a monoclonal antibody complement inhibitor, is also being studied for its potential as a treatment for C3 glomerulopathy.
Although more treatments are now available for people with C3 glomerulopathy, the outcomes vary. However, not everything is out of your control — you can make lifestyle changes to improve your health and lower your chance of kidney failure. Your doctor may recommend following a kidney-friendly diet and exercising to maintain a healthy weight and help manage your C3 glomerulopathy.
Smoking and heavy drinking can make kidney disease worse, so if you smoke cigarettes or drink alcohol, quitting may improve your outcome. Read more about ways to improve life expectancy with kidney disease.
Although the future may be uncertain, you can follow up with your doctor to plan your next steps. With healthy habits and more effective treatments, you can better manage your C3 glomerulopathy and live a longer, healthier life.
MyKidneyDiseaseTeam is the social support network for people with kidney disease and their loved ones. On MyKidneyDiseaseTeam, members come together to ask questions, give advice, and share their stories with others who understand life with kidney disease.
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