People with rheumatoid arthritis (RA) have a slightly higher risk of developing kidney disease. It is one of the facts about RA which reminds you that this is a serious illness.
What do kidneys do?
You have two kidneys, located on either side of the spine around your lower rib cage. Your kidneys are responsible for removing waste and excess fluid from your body. They do this through urine. Kidneys also help maintain and regulate salt, potassium, and acid in the body, as well as produce hormones and vitamins. When kidney function is impaired, waste products and water build up in the body, causing swelling and symptoms of kidney failure (also called uremia).
The link between RA and kidney disease
When you live with RA, you have a higher risk of complications or comorbidities, that is, medical conditions that are related to RA. Kidney disease is one of these conditions. In fact, people who have RA have a one in four chance of getting kidney disease, as compared to one in five of the general population. There is also a link between kidney disease and heart disease in people with RA. As RA already increases the risk of heart disease, it’s important to manage both these risks as much as you can.
Two factors contribute to kidney disease in people with RA. One is inflammation. RA is a systemic illness, affecting not just the joints, but also other systems in the body, including organs and the vascular system. It is inflammation in the vascular system that increases your risk of heart disease. This inflammation can contribute to reduced kidney function through its effects on the heart and blood vessels. Rarely, inflammation in RA can also directly affect the filters in the kidneys leading to a group of diseases called glomerular diseases.
The second factor that increases the risk of kidney disease in people with RA is the medications we take. Although drugs like NSAIDs are generally considered safe in younger people with normal kidney function, they were shown to double the risk of kidney injury in older adults. The risk of kidney injury is also higher in those with reduced kidney function, in those taking medicines such asdiuretics, certain blood pressure medications, and in those who have diarrhea or vomiting. People taking NSAIDs should see their doctors regularly and have periodic blood tests to measure creatinine level, a marker of kidney function. Moreover, the kidneys play a crucial role in eliminating other medications used in in RA such as methotrexate. If you have reduced kidney function, the medication can build up in your bloodstream. It’s why people taking methotrexate should have regular blood tests to monitor kidney function.
General risk factors related to kidney disease include diabetes, high blood pressure, high cholesterol, and heart disease. As well, according to the Centers for Disease Control, African-Americans are three and a half times more likely to develop kidney disease than Caucasian individuals.
Signs of kidney disease
Kidney disease may not become noticeable until it’s advanced, so it’s important to have kidney function measured periodically through blood tests. You should also be aware of the signs that you may have trouble. The symptoms of kidney disease include
- feeling tired, having low energy
- trouble concentrating
- low appetite
- difficulty sleeping
- swollen feet and ankles
- puffiness around the eyes, particularly in the morning
- muscle spasms, especially at night
- need to pee more often, especially at night
You may be looking at that list, already convinced you have kidney disease. A number of those symptoms are symptoms of RA. So how do you know the difference? More on that in the next section.
How to protect your kidneys
By now you might feel very anxious about your kidneys. Relax. There are a number of things you can do to protect yourself, some involve your doctor, other things you can do yourself every day.
First, make sure your RA is controlled by taking medications that suppress the disease. The less inflammation there is in your body, the better protected your kidneys are. The medications that control your RA are DMARDs and Biologics. NSAIDs alone only address symptoms, and may in fact contribute to kidney problems.
Talk to your doctor about how to manage the risk of kidney disease. One way to do this is to perform regular blood and urine tests to monitor your kidney function. How often you should do these tests depends on your general health and the medications you take.
Have an annual physical. Make sure that your family doctor tests for blood sugar, cholesterol, and blood pressure. Know your blood creatinine level, which is a marker of kidney function, and is part of routine blood testing. As well, you may want to ask for a referral to a preventative cardiologist to help manage the increased risk of heart disease that accompanies RA. Making sure your cholesterol and blood pressure are controlled is an important part of managing the risk of heart disease.
Be careful about your salt intake. Too much salt can contribute to high blood pressure, which can impact kidney health.
And, lastly, avoiding dehydration is important to good kidney function. Avoid taking NSAIDs when you are dehydrated due to diarrhea or vomiting, or after exercising outdoors on a hot day. Stay away from soda and caffeinated beverages. Instead, carry a bottle of water with you. If the taste bores you, add a slice of lemon or other fruit to infuse the water with flavor. This will help you gradually increase your fluid intake.
Learning more about complications and comorbidities of RA can be scary. No one likes to hear about increased risks of heart disease or the possibility of kidney disease. It’s tempting to stick your head in the sand and avoid frightening information, but this can ultimately get you into more trouble. Knowing as much as possible about your RA can help you manage the risk. In the case of kidney disease, some fairly simple measures can help you stay ahead of the risk and address any problems before they grow big and unmanageable.