Rheumatoid Sarcopenia: What You Need to Know

How Exercise and Rheumatoid Arthritis Treatment Can Help

Physical therapist helping patient strengthen arms
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You may have come across the term sarcopenia when learning about rheumatoid arthritis. Just what is sarcopenia, and why should you be concerned about it? What steps can you take to help address it?

What Is Sarcopenia?

In general, sarcopenia is a condition causing a worsening loss of skeletal muscle tissue. It can be considered a type of muscle wasting.

Originally researchers used the term to describe muscle wasting that happens during normal aging but more recently, some have started using the word to describe muscle wasting that can be triggered or worsened by certain medical conditions, such as rheumatoid arthritis.

Compared to people without rheumatoid arthritis, people with rheumatoid arthritis are more likely to experience severe muscle wasting that occurs earlier in life. This is sometimes called rheumatoid sarcopenia.

Normal Muscle Use

You use skeletal muscles to make voluntary movements of your limbs, torso, and other parts of your body. These skeletal muscles are composed of individual long muscle fibers. These fibers contain special proteins that can pull tightly against each other to shorten muscles, or relax to let muscles lengthen. 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.

Changes in Sarcopenia

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 of the proteins used in muscle movement start to break down, and cellular repair systems do not work as well to repair them.
  • Some muscle fibers may be replaced with fatty tissue.

Problems From Sarcopenia

Because of all this, the muscle becomes smaller.

Not surprisingly, this can lead to a number of problems, including the following:

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

What Causes Sarcopenia?

Sarcopenia occurs as part of aging, even in people who do not have rheumatoid arthritis. By the 8th decade of life, many people have lost up to 50 percent of their original muscle mass. Many different 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

Inflammation Triggering Sarcopenia in Rheumatoid Arthritis

Inflammation is an especially important trigger for sarcopenia in people with rheumatoid arthritis. 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.

In rheumatoid arthritis, this inflammatory response is heightened. 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 symptoms of rheumatoid arthritis like joint pain and swelling. (This is why some drugs used to treat rheumatoid arthritis, such as TNF-inhibitors, are designed to help block these cytokines.)

These inflammatory cytokines have other effects, including increased muscle breakdown. That’s why people with rheumatoid arthritis are more likely to have earlier-onset sarcopenia and more severe sarcopenia. Among patients with rheumatoid arthritis, people who have higher levels of these inflammatory cytokines have a greater risk of having sarcopenia and decreased muscular strength.

Other Factors Triggering Sarcopenia in Rheumatoid Arthritis

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 rheumatoid arthritis, you may avoid physical activity that worsens these symptoms. Over time this can cause a type of muscle atrophy called disuse atrophy. Simply put, this is decreased muscle size that occurs when a muscle doesn’t get enough regular exercise.

People with active rheumatoid arthritis may also be using more protein and calories than normal because of their disease. Since protein is needed for muscle maintenance, this can also worsen rheumatoid sarcopenia.

Diagnosis of Rheumatoid Sarcopenia

Ask your doctor if you have any concerns about decreased muscle strength due to rheumatoid arthritis. Your doctor can use different tests to see if you might have sarcopenia. These may include the following:

  • BIA test (bioelectrical impedance analysis)
  • DEXA test (dual-energy X-ray absorptiometry)
  • Tests to assess muscle strength and overall physical performance

A BIA is a noninvasive test that 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.

Another option is the DEXA test (more commonly used to evaluate osteoporosis). This is another painless test that uses an X-ray with a very low level of radiation. In this case, it can be used to calculate a value called lean body mass (LBM), another measure of muscle mass.

Your doctor 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. In rheumatoid sarcopenia, part of the muscle protein fibers may be replaced with fat. Because of this, weight might not change very much, even if a person has lost functional muscle fibers. That is why body mass index (BMI) is not a good test for rheumatoid sarcopenia. This test doesn’t measure whether mass is coming from muscle or from fat. Some people with rheumatoid sarcopenia will have reduced BMI, but in some people BMI may be normal or even increased.

Rheumatoid Cachexia

Another related term you might hear is rheumatoid cachexia. Cachexia refers to a condition of severe weight, fat, and muscle loss that occurs due to a major medical condition, such as cancer. By definition, most people with rheumatoid cachexia also have rheumatoid sarcopenia. But not everyone with rheumatoid sarcopenia has rheumatoid cachexia.

However, even researchers don’t always use these terms consistently. The topic can be confusing for both doctors and patients, because medical societies have not developed rigorous criteria to diagnose people with rheumatoid sarcopenia and rheumatoid cachexia. Partly because of this, we don’t have good estimates for the prevalence of these conditions. We do know that most patients with rheumatoid arthritis have at least some degree of muscle weakness.

Preventing and Treating Rheumatoid Sarcopenia

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

  • Optimize disease treatment of rheumatoid arthritis itself.
  • Pursue an adequate and consistent exercise regimen.

Keeping your rheumatoid arthritis itself under control is one of the best things you can do to prevent and treat rheumatoid sarcopenia. Drugs such as TNF-blockers and IL-6 inhibitor drugs can help tamp down the inflammation that worsens 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. However, secondary evidence suggests that these drugs might be beneficial.

We also don’t have much data comparing the effectiveness of different disease-modifying anti-rheumatic drugs (DMARDS) in treating sarcopenia. It is known that long-term treatment with corticosteroids can make sarcopenia worse. Over time, researchers will learn more about which specific disease treatments might be the best ones for patients with sarcopenia.

Exercise Treatment

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

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

Weights, resistance bands, or the person’s own body weight can be used to make the 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 (such as swimming) can play a protective role. Ask your doctor for advice in 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 rheumatoid arthritis. 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. Eating a heart-healthy diet containing enough protein and calories may also help prevent rheumatoid sarcopenia.

A Word From Verywell

Dealing with rheumatoid sarcopenia can be frustrating. But knowing you are at risk of muscle loss can provide extra motivation. To minimize the impact of sarcopenia, keep your disease well-controlled with medication and pursue a consistent exercise program.

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Doğan SC, Hizmetli S, Hayta E, Kaptanoğlu E, Erselcan T, Güler E. Sarcopenia in women with rheumatoid arthritis. European Journal of Rheumatology. 2015;2(2):57-61. doi:10.5152/eurjrheum.2015.0038.

Masuko K. Rheumatoid cachexia revisited: a metabolic co-morbidity in rheumatoid arthritis. Frontiers in Nutrition. 2014;1:20. doi:10.3389/fnut.2014.00020.

Targowski T. Sarcopaenia and rheumatoid arthritis. Reumatologia. 2017;55(2):84-87. doi:10.5114/reum.2017.67603.

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