Rheumatoid arthritis (RA) typically affects the joints of the small bones of the hands and the lining of joints throughout the body. Affected joints will become painful, red, and swollen, and over time, ongoing inflammation may cause joints to become deformed and damaged.
Because RA is a systemic and progressive disease, it can lead to inflammation that can wreak havoc on major organs, including the kidneys. The effects RA can have on your kidneys can be quite extensive and those effects can be far-reaching and sometimes, life-threatening. Here is what you need to know about RA’s effects on your kidneys and what you can do to reduce your risk for kidney problems.
Your two kidneys have important jobs when it comes to keeping you healthy. Their main job is to remove waste and extra water out of your body. They are also responsible for producing hormones that regulate blood pressure, nourish blood cells, and keep bones strong.
When there is kidney damage that leads to the kidneys being unable to filter blood, this condition is called chronic kidney disease (CKD). CKD leads to a waste buildup in the body and other problems that can adversely affect your health.
According to the National Kidney Foundation, there are about 37 million Americans living with CKD and millions more who are at an increased risk for kidney disease.
People with RA have a 1 in 4 chance of developing CKD, according to a study reported in 2014 out of the Mayo Clinic. In this study, researchers compared 813 people with RA and 813 people without the condition over a 20 year period.
Here, Mayo Clinic researchers concluded the risk of CKD was much higher in people with RA compared to the risk for people without the condition who had a 1 in 5 chance of developing kidney disease.
The researchers further noted that while this doesn’t appear to be a significant difference, it is important in terms of the complications that RA can cause and what interventions need to be taken to reduce the risk of kidney disease in RA. Risk factors to kidney disease in people with RA are inflammation and the medications that treat RA.
The exact relationship between chronic inflammation and CKD isn’t always clear in people with RA, but researchers speculate certain inflammatory proteins play a part. This means the more severe your RA is (characterized by high levels of inflammation), the higher your risk for kidney problems.
Uncontrolled inflammation can damage the linings of the kidneys and lead to a condition called atherosclerosis where plaque builds up on the inside of the renal arteries (the arteries of the kidneys).
With time, plaque buildup will cause hardening and narrowing of the arteries and blood vessels and lead to reduced blood flow to the kidneys, eventually causing the affected kidneys to lose function.
A study reported in 2016 in the journal PLoS One aimed to examine the relationship between C-reactive protein (CRP) inflammatory markers and the incidences of CKD in people with RA. In this study, researchers found high CRP levels were a significant risk factor for CKD and persistent inflammation increased the risk for CKD in people with RA.
Another study—this one going back to 2011 and published in The Journal of Rheumatology—looked at the effects of cystatin C—an important biomarker of renal function. Here, researchers found cystatin C to be elevated in people with RA, especially those who experienced high levels of inflammation.
High cystatin concentrations are considered indicators of undetected kidney dysfunction. They are also connected to a higher risk of atherosclerosis in people with RA, both renal and cardiovascular.
Another potential kidney concern for people with RA is amyloidosis, especially for people with long-standing and poorly controlled RA. Amyloidosis causes abnormal levels of the protein amyloid to build up in organs. In people with RA, the disease causes the amyloid to build up in the kidneys.
Research also shows a connection between RA and a condition called glomerulonephritis—inflammation of the filtering units of the kidneys called (the glomeruli). Inflamed glomeruli can impair kidney function and lead to chronic kidney disease.
Heart problems also play a role in the development of kidney disease in people with RA. This is because there are higher incidences of high blood pressure and other risk factors of cardiovascular disease (also called heart disease) in people with RA.
That increased risk, according to a Taiwanese study reported in the journal PLoS One, is related to inflammation, comorbidities like cardiovascular disease, and renal toxicity from the very drugs prescribed to treat RA. The risk for CKD in people with RA, as noted by the study’s authors, is still high even without comorbid conditions.
The study’s authors also stressed the importance of careful monitoring of renal health in people with RA, as well as tight control and management of comorbid conditions and risk factors for heart disease and kidney disease.
The majority of the medications your doctor has prescribed to treat RA do not directly affect your kidneys. However, there are some that can increase the risk of reduced kidney function, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, methotrexate, and cyclosporine.
For most healthy people, kidney damage from NSAID use is uncommon. However, taking higher doses of NSAIDs to manage pain and inflammation might lead to NSAID nephrotoxicity—the rapid deterioration of the kidneys due to the toxic effects of NSAIDs.
Frequent NSAID use, as well as other pain relievers that contain acetaminophen, can also lead to nephropathy. This condition means there is damage to the small blood vessels in the kidneys that clean the blood.
Talk to your doctor if you concerned about the number of NSAIDs you are taking to manage pain and inflammation. They can help you help to find alternative pain relief options.
While corticosteroids do not directly cause kidney damage, they can lead to fluid retention, which raises blood pressure. With time, this can aggravate existing kidney issues or lead to kidney problems with continued use of corticosteroids.
Methotrexate is the most effective medication available to treat RA and one of the first drugs doctors prescribe for treating the disease. It can ease symptoms like joint pain, fatigue, stiffness, and swelling and may reduce inflammation and prevent damage to joints.
Methotrexate is eliminated through the kidneys. In people who take high doses of methotrexate, there might be a buildup of the drug in the bloodstream, potentially causing an overdose. Research shows at least 1.8% of people who use methotrexate experience some type of kidney dysfunction.
Cyclosporine is a powerful immunosuppressant that may decrease kidney function. Most people who experience kidney dysfunction while using cyclosporine have used it for long periods and take high doses of the drug.
Fortunately, people who experience kidney problems with cyclosporine will have mild issues that can be resolved by adjusting the dosage or discontinuing the medication.
Other Risk Factors
RA isn’t the only risk factor that can damage the kidneys and lead to kidney disease. Other risk factors for kidney disease include:
Diabetes is one of the strongest risk factors for kidney disease. The term “diabetes” refers to a group of conditions that affect the body’s ability to control blood sugar.
People with uncontrolled diabetes can quickly and easily progress to end-stage kidney disease. End-stage means your kidneys are no longer able to meet your body’s needs.
A study presented at the 2020 European Association for the Study of Diabetes (EASD) suggests people with RA are at a nearly 23% increased risk for the development of RA compared to others in the general population.
EASD researchers believe this might be an indication that both diseases are linked to the body’s inflammatory response. Having diabetes with RA, or risk factors for diabetes with RA, can add to your heightened risk for CKD.
High Blood Pressure
After diabetes, high blood pressure is the next big risk factor for kidney disease. Up to 27% of people with end-stage kidney disease also have high blood pressure, according to a 2013 report in the journal Kidney International Supplements.
A number of factors increase blood pressure in people with RA, including lack of physical activity and drugs that treat the condition like NSAIDs and corticosteroids. People with RA may also develop narrowed arteries from ongoing inflammation, which will make it harder for blood to pass through and lead to increased blood pressure.
Blacks are more likely to have kidney disease than people of other races. Researchers do not know why these high incidences exist in this group, but they speculate it might be because diabetes and high blood pressure are common among Blacks.
Family members of people with kidney disease have a high prevalence of the condition and other risk factors that can lead to the development of kidney dysfunction.
People over age 60 have an increased risk for kidney disease because their kidneys do not work as well as they used to. Additionally, they are also more likely to have diabetes, high blood pressure, or both. If you are over age 60, ask your doctor about getting tested for kidney disease.
Heart disease can lead to kidney disease, and kidney disease can cause heart disease. Heart disease is also the most common cause of death for people on dialysis. Dialysis treatment for people whose kidneys have failed involves ridding the body of unwanted toxins, waste products, and excess fluid by filtering their blood.
The risk for heart disease in people with RA is twice that of others in the general population. That means if you develop kidney disease or heart disease, your risk for the other condition is going to be much higher with RA.
Smoking can cause kidney disease through inflammation and oxidative stress. Oxidative stress means there is an imbalance between free radicals and antioxidants in your body). Free radicals are linked to aging and a host of diseases. Antioxidants are compounds that inhibit oxidative stress.
In addition to contributing to kidney problems, smoking is also associated with more severe RA, more joint damage, loss of function and disability, and disease complications like vasculitis (blood vessel inflammation) and rheumatoid lung disease.
Obesity is a controllable risk factor for kidney disease that can contribute to the development of kidney disease through inflammation, oxidative stress, coronary disease, abnormal blood coagulation, and hypervolemia (a condition where there is too much fluid in the blood).
Acute Kidney Injury
Adults with a history of acute kidney injury have a 10 times greater risk for kidney disease than people who have not had an injury, according to one report in the journal Kidney International Supplements.
Preventing Kidney Problems
One of the best ways to protect your kidneys when you have RA is to keep inflammation in check. Your doctor will put you on a variety of medications to keep your inflammation down. But because these drugs can affect kidney function, your doctor should also monitor you regularly to check for kidney problems.
Blood and urine tests are used to assess kidney function. Testing should be done at least once a year. If your doctor has not requested such testing for you or you are unsure, you should speak up and ask them to set up testing.
If you have other risk factors for kidney disease, you should work with your doctor to reduce those. Talk to your doctor about:
- The benefits and risks of the medications you take to treat RA
- Losing weight or maintaining a healthy weight
- Following a low-sodium diet—a high sodium diet is another risk factor for kidney problems
- Keeping blood pressure levels managed
- Keeping your cholesterol in check, including with diet and medication
- Help for quitting smoking
Being active can help reduce many risk factors for kidney disease, including RA. Regular, low-impact exercise can reduce inflammation, keep your weight managed, and lower your blood pressure.
Just make sure you don’t overdo it. Ask your doctor or physical therapist for advice on how you can exercise safely with RA.
Your diet can is another way to reduce your risk of kidney problems. It will also help you to manage RA disease symptoms like inflammation and joint pain.
Choose foods that are healthy for your entire body, especially your heart. This should include a variety of fruits and vegetables, whole grains, lean meats, low-fat and fat-free dairy, and foods that are part of an anti-inflammatory diet. Aim for no more than 2,300 milligrams of sodium daily.
A Word From Verywell
Rheumatoid arthritis is a chronic disease, which means you will be living with it for the rest of your life. It is, therefore, important to manage it properly so it doesn’t lead to other serious health problems like kidney disease.
Some simple lifestyle changes and vigilance can help you to get ahead of kidney problems. And if you find you are struggling to keep inflammation and other conditions under control, make sure you reach out to your doctor before things worsen and your quality of life is affected.