Arthritis, a disease characterized by inflammation of joints, is a painful and disabling disease that leads to joint stiffness and pain. Patients with arthritis also have a higher risk of developing several complications, including metabolic syndrome. The incidence of metabolic syndrome has been shown to be higher in patients with specific types of arthritis, such as psoriatic arthritis or rheumatoid arthritis, compared to healthy people.
What causes metabolic syndrome?
The exact cause of metabolic syndrome is not currently known. However, many characteristics of metabolic syndrome are associated with "insulin resistance”, which is a condition in which the body does not use insulin efficiently to lower glucose (sugar) and fat levels. Insulin resistance itself is the result of a combination of genetic and lifestyle factors such as diet, activity and sleep patterns.
Risk factors for metabolic syndrome
Metabolic syndrome is fairly common as it affects more than one in five Americans. The characteristics of people that are most likely to get metabolic syndrome include:
- Older individuals. The risk of metabolic syndrome goes up with age — over 40 percent of people their 60s and 70s are estimated to have it.
- Individuals who are obese, specifically individuals with centralized obesity (higher levels of fat in the waist).
- Individuals with diabetes or a family history of diabetes.
- Individuals that have other features characteristic of "insulin resistance" such as "darkened skin" on the back of the neck or underarms.
- People with specific ethnicities. Mexican-Americans are at the greatest risk of developing metabolic syndrome.
Symptoms of metabolic syndrome
Metabolic syndrome doesn't usually cause immediate physical symptoms. However, issues related to metabolic syndrome will develop gradually. A large waist or a large circumference of the waist is a physical sign of metabolic syndrome. Other symptoms include:
- Increased thirst
- Increased urination
- Fatigue or weakness
- Blurred vision
Metabolic syndrome: Diagnosis
If your physician suspects that you may have metabolic syndrome, then he or she will conduct a physical examination, go through a detailed medical and personal history, and order a range of tests that will involve looking at blood pressure, fat profiles (triglycerides and HDL), and blood glucose levels.
In order to be diagnosed with metabolic syndrome, patients need to meet at least three or more of the following five criteria:
- A waistline circumference, which is measured across the belly, of 40 inches or more for men and 35 inches or more for women.
- The patient must either be on blood pressure medication or have a blood pressure level of 130/85 mmHg or higher.
- Triglyceride level over 150 mg/dl.
- The patient must either be on glucose-lowering medications (such as insulin) or have a fasting blood glucose (sugar) level of more than 100 mg/dl.
- High density lipoprotein (a type of cholesterol) level of less than 40 mg/dl (men) or under 50 mg/dl (women).
Complications associated with metabolic syndrome
These are the complications that can develop in patients with metabolic syndrome:
- Cardiovascular disease. Patients with metabolic syndrome are more likely to damage their arteries, leading to heart disease or stroke.
- Kidney problems. Metabolic syndrome can cause changes in the kidneys' ability to remove unwanted substances.
- Increased risk of blood clot formation, which can also lead to heart disease and stroke.
- Diabetes, as patients with metabolic syndrome have reduced production of insulin.
Rheumatoid arthritis and metabolic syndrome
Patients with rheumatoid arthritis are significantly more likely to have metabolic syndrome compared to the general population. In fact, one study shows that patients with rheumatoid arthritis are 1.44 times more likely to develop metabolic syndrome compared to the general population.
Additionally, studies have found a correlation between the prevalence of metabolic syndrome and worsening of functional status in patients with rheumatoid arthritis. Researchers suggest that inflammation in rheumatoid arthritis contributes to the development of metabolic syndrome in these patients. Consequently, the combination of the two diseases serves to worsen the patients’ functional status.
There is a well-established link between metabolic syndrome and the development of cardiovascular diseases, which makes patients with rheumatoid arthritis more susceptible to cardiovascular diseases. Thus, it is important to monitor the development of metabolic syndrome in rheumatoid arthritis and work to improve modifiable risk factors (such as weight).
Psoriatic arthritis and metabolic syndrome
Patients with psoriatic arthritis are also significantly more likely to have metabolic syndrome compared to the general population. One study demonstrated that being older, combined with more severe and extensive psoriasis, was linked to a higher likelihood of developing metabolic syndrome. Patients with both psoriatic arthritis and metabolic syndrome usually suffer from more severe psoriatic arthritis symptoms, and they're also less likely to get their disease under control. Similar to rheumatoid arthritis, patients with psoriasis have an increased risk of developing metabolic syndrome due to the fact that it’s a chronic inflammatory condition.