Rheumatoid Sarcopenia: What You Need to Know

Rheumatoid sarcopenia is a type of muscle wasting (skeletal muscle loss) that affects some people with rheumatoid arthritis (RA). Originally, researchers used the term sarcopenia to describe muscle wasting that happens during normal aging. More recently, though, some have started using the word to describe muscle wasting that's triggered or worsened by certain medical conditions, such as RA.

For several reasons, people with rheumatoid arthritis are more likely than others to experience muscle wasting earlier in life.

Your Muscles

To understand why sarcopenia develops, it's helpful to understand a bit about how your muscles normally work.

You use skeletal muscles to move all the parts of your body. They're made up of individual fibers containing special proteins that allow them to lengthen or shorten your muscles. They respond to signals from neurons (and, ultimately, from the brain) to let you move your body. Other cells in the muscle work to repair the normal wear and tear on muscle tissue so it doesn’t degrade over time.

In sarcopenia, a number of changes occur inside the muscle:

• Some of the muscle fibers start to degrade.
• Some muscle fibers lose their connections to neurons.
• Muscle fibers decrease in overall size.
• Muscle fibers decrease in total number.
• Some proteins used in muscle movement start to break down.
• Cellular repair systems become unable to prevent degradation.
• Some muscle fibers may be replaced with fatty tissue.

These changes are what lead to the symptoms of sarcopenia.

Rheumatoid Sarcopenia Symptoms

Rheumatoid sarcopenia can cause a number of symptoms, including:

• Decreased muscle strength
• Greater disability
• Increased frailty
• Poorer balance
• Increased risk of serious falls (which may be life-threatening)
• Overall reduced quality of life

Causes

Sarcopenia occurs as part of aging, even in people who are otherwise healthy. By their 80s, many people will lose up to 50% of their original muscle mass. Many factors can play a role in this loss, including:

• Declines in certain hormones
• Altered muscle physiology
• Reduced numbers of muscle stem cells
• Poor nutrition
• Decreased physical activity
• Increased chronic inflammation

Sarcopenia is believed to be more common in RA due to several factors that can trigger the process of muscle breakdown. These include inflammation, pain and its impact on lifestyle, and the physical demands of the disease itself.

Inflammation

Inflammation is an especially important trigger for sarcopenia in people with RA. During inflammation, specific immune cells of the body release inflammatory cytokines. These are specific signaling molecules that trigger an inflammatory response in the body. This response is partially responsible for the decreased muscle mass found in older adults.

People with RA have a heightened inflammatory response. Immune cells release greater amounts of inflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α). Ultimately, these cytokines help trigger the RA symptoms of joint pain and swelling. (This is why some drugs used to treat rheumatoid arthritis, such as TNF-inhibitors, are designed to help block cytokines.)

Inflammatory cytokines have other effects as well, including increased muscle breakdown. That’s why people with rheumatoid arthritis are more likely to have earlier-onset sarcopenia and more severe sarcopenia than people who don't have the disease.

Pain

Pain itself is another major factor increasing the risk of sarcopenia in people with rheumatoid arthritis. If you have untreated pain and stiffness from your RA, you may avoid physical activity that makes you feel worse. Over time, this can cause a type of muscle atrophy called disuse atrophy.

In other words, if you don't exercise a muscle enough, it gets smaller and weaker, compromising its health.

Physical Demands

With RA, the disease itself places high demands on the body. The immune system is locked in a never-ending battle to destroy the joint lining. The body is also working constantly to replace damaged tissues.

It takes protein and calories to sustain that. The process robs the body of resources it could otherwise use to maintain muscle health, which can contribute to rheumatoid sarcopenia.

Diagnosis

If you have RA and have noticed a decrease in your muscle strength, let your healthcare provider know so they can check for sarcopenia. Tests may include:

• Bioelectrical impedance analysis (BIA) test: This noninvasive test works by sending an extremely low-level current through the body. Different types of tissue slow down the flow to different degrees. Based on the calculated resistance to this electrical flow, a technician can estimate a value called fat-free mass (FFM), which can be used to assess muscle mass.
• Dual-energy X-ray absorptiometry (DEXA) scan: This involves an X-ray with a very low level of radiation that calculates your lean body mass (LBM)—another measure of muscle mass. DEXA is also used to evaluate osteoporosis.
• Muscle-strength and physical-performance assessments: Your healthcare provider may also ask you to perform various physical tasks such as walking quickly or squeezing a handgrip device.

Note that people with rheumatoid sarcopenia do not necessarily lose body weight overall. Because part of the muscle fibers may be replaced with fat, your weight might not change very much, even if you've lost a lot of muscle.

Prevention and Treatment

Researchers haven’t established clear guidelines for the treatment of rheumatoid sarcopenia. However, experts recognize two general strategies for both prevention and treatment:

• Optimize disease treatment of RA itself
• Pursue an adequate and consistent exercise regimen

Some healthcare providers also recommend dietary changes and supplements.

Disease Management

Keeping your RA under control is one of the best things you can do to prevent rheumatoid sarcopenia and treat it if it does occur. Drugs such as TNF-blockers and IL-6 inhibitor drugs can help tamp down the inflammation associated with rheumatoid sarcopenia.

Currently, there isn’t a lot of specific research about whether these long-term inflammatory treatments might help improve sarcopenia over the long-term. But secondary evidence suggests that these drugs might be beneficial.

Also lacking is much data comparing the effectiveness of different disease-modifying anti-rheumatic drugs (DMARDs) in treating sarcopenia. Experts have seen that long-term treatment with corticosteroids might make sarcopenia worse, however. Research is ongoing, so researchers will likely learn a lot more about the condition itself and how to treat it.

Exercise

Exercise is the other key component in addressing rheumatoid sarcopenia. Evidence suggests that resistance training in particular may help with all of the following:

• Increasing muscle strength
• Decreasing levels of disease activity
• Decreasing pain

Weights, resistance bands, or your own body weight can be used to make muscles work hard for a short period of time. This type of strength training can help prevent the muscle atrophy characteristic of rheumatoid sarcopenia.

Evidence also suggests that aerobic endurance exercise (e.g., swimming) can play a protective role. Ask your healthcare provider for help shaping a specific exercise plan. You may find it helpful to work with a personal trainer for a period of time.

Keeping up a regular exercise program may provide another benefit for people with RA. The disease seems to cause an increased risk of heart disease, but a regular exercise program may help reduce the risk for heart attack and related problems.

Diet and Supplements

Eating a heart-healthy diet containing enough protein and calories may also help prevent rheumatoid sarcopenia.

Furthermore, some studies on sarcopenia in general have shown that a balanced, high-protein diet can be beneficial. Talk to your healthcare provider about what this means for you and consider whether it might help to see a nutritionist.

Research also suggests that essential amino acids, vitamin D, and omega-3 supplements may help treat sarcopenia.

A Word From Verywell

The good news is that sarcopenia prevention isn't really any different from good RA management. Knowing you're at risk of muscle loss can provide you with extra motivation to take care of yourself. The key is to work with your healthcare provider, find the treatments that work for you, and stick to them.